Electro-optical protective sheet, and radiation protection device

Abstract

The invention relates to an electro-optical protective sheet (S) for a radiation protection device, in particular a light protection device, comprising a front-facing sheet (1), preferably made of plastics material, and at least one liquid crystal element (2) having a controllable degree of transmission on at least one side of the front-facing sheet (1). At least one control electronics (6) for the at least one liquid crystal element (2) is also provided, or at least one contact (7) is present for connection to such a control electronics (6). A portion (3) of the area of the front-facing sheet (1) at the edge of the front-facing sheet (1) has a degree of transmission that is preferably constant, and is permanently lower than that of the remainder of the area of the front-facing sheet (1).

Description

[0001] ELECTRO-OPTICAL PROTECTIVE SCREEN AND RADIATION PROTECTION DEVICE

[0002] The invention relates to an electro-optical protective screen, according to the preamble of claim 1, and to a radiation protection device, in particular a light protection device, with such a protective screen, according to the preamble of claim 9.

[0003] It is known to provide an electro-optical protective screen that covers at least the field of vision of one eye and comprises at least one liquid crystal element whose transmittance can be controlled by means of control electronics. It is also known to provide radiation sensors and generate a control signal depending on the intensity of the incident radiation, and then control the transmittance of the protective screen as a function of the control signals from the radiation sensors. The or each liquid crystal cell is preferably attached to a cover screen, which is preferably made of plastic material. At least the contacts for connecting to the control electronics are arranged on the protective screen.

[0004] For example, EP 3 258 306 B describes a sun protection device, in particular sunglasses, with at least one optical sun protection filter having at least one liquid crystal cell, and with at least one sensor unit provided for detecting solar radiation. Preferably, the sun protection device also has a control and / or regulating unit provided for controlling and / or regulating a transmittance of the optical sun protection filter depending on solar radiation. A sensor surface of the at least one sensor unit is at least partially covered by at least one sensor cover, which is at least partially at least substantially opaque to radiation of a visible light spectrum.

[0005] EP 3 223 067 A likewise discloses a sun protection device as explained above, comprising at least one control and / or regulating unit provided for controlling and / or regulating a transmittance of the optical sun protection filter depending on solar radiation. In at least one operating state, the control and / or regulating unit is provided for controlling and / or regulating the at least one liquid crystal cell of the optical sun protection filter to generate a defined transmittance profile with at least two differing transmittances. WO 2022 / 038014 A1 describes an embodiment of a sun protection device whose optical sun protection filter has at least one photochromic protective element in addition to the optical sun protection filter.

[0006] US Pat. No. 5,552,841 A discloses spectacles with electronically dimmable lenses via liquid crystal cells, which darken depending on the incident radiation. Power is supplied via a film applied to the lenses. Furthermore, a rechargeable battery can be provided, and a dedicated dimming control unit with a manual adjustment knob can be arranged between the solar cell and the lens. One embodiment of these spectacles provides at least one infrared sensor, the output signal of which is used to control the dimming. The dimming can extend across the height of the lens and, if necessary, can also be manually adjustable.

[0007] The object of the present invention was to design a device for controllable, but in any case optimized, radiation protection.

[0008] This object is achieved by a device according to the claims.

[0009] To achieve this object, an electro-optical protective screen for a radiation protection device, in particular a light protection device, is characterized in that a partial area of ​​the surface of the additional screen has a permanently lower and preferably constant transmittance than the remaining area of ​​the surface of the additional screen. This partial area is preferably located at the edge of the protective screen, in particular at the upper edge and centrally for the or each protective screen, in order to restrict the field of vision as little as possible and not to obstruct the view. Another possibility would be the area which, when the radiation protection device is in place, is located in the area of ​​the nose, the bridge of the nose, or the root of the nose. This area can, for example, extend vertically from a nose cutout to the upper edge or, in the case of protective screens for spectacle-like embodiments, be located in the central edge area. This ensures an optimal positioning and / orA specially prepared location is provided for the attachment of additional modules, which in any case prevents the transmission of radiation, even with a distributed design of these additional modules, and ensures optimal shielding. This applies in particular to a completely opaque design of the partial area or the highest possible blackening. When used on sunglasses, ski goggles, or welding helmets, for example, this ensures the best possible shading even against radiation, especially light, which enters from an angular range that deviates significantly from the optical axis of the protective screen and strikes the narrow side of the liquid crystal cell at an angle and is scattered or refracted onto the back of the protective screen into the area to be shielded.

[0010] Preferably, the liquid crystal element has a cutout at the location and of essentially the same size as the portion of the cover plate with the lower transmittance. This enables optimal radiation protection while simultaneously keeping the thickness of the protective plate low, since all additional components can be arranged in the same plane as the liquid crystal element.

[0011] A further embodiment of the invention is characterized in that the partial area with a lower transmittance is formed by a layer of a material with a lower transmittance applied to the cover plate. Printing is preferably provided, in particular pad printing. However, any method that results in a reduction in the transmittance can be used, i.e., any type of coating, coating, or laser treatment.

[0012] Advantageously, it is further provided that the sub-area with lower transmittance itself consists of at least two sub-areas that have different and preferably constant transmittances and / or different spectral transmission characteristics. The use of areas with constant transmittance results in a very simple embodiment, which avoids additional control effort for the sub-area of ​​the protective screen. Different spectral transmission characteristics enable the optimal design of the sub-area for the positioning of additional components such as sensors, photocells, or the like, whose highest sensitivity may lie in a different part of the spectrum of the incident radiation than the part to be shielded.

[0013] Preferably, the control electronics are also positioned within the sub-area with the lower transmittance and fixed to the cover plate. This makes it possible to produce a fully functional protective plate for installation in a wide variety of support systems, which is also very thin and thus versatile. A further alternative embodiment of the invention is characterized in that at least one radiation sensor connected or connectable to the control electronics is positioned within the sub-area with the lower transmittance and fixed to the cover plate and / or the control electronics. Preferably, the sensor(s) is / are positioned in those sub-areas that have the highest transmittance. Alternatively or additionally, the sensors can be positioned in a sub-area that has the highest transmittance in the spectral range of their highest sensitivity.

[0014] The radiation sensors preferably have their highest transmittance in the range between 400 and 1100 nm, preferably in the infrared range. At the same time, the sub-range preferably has its highest transmittance in this wavelength range.

[0015] A further embodiment of the invention is characterized in that the sub-area with the lower transmittance is arranged near the upper edge of the cover panel. This arrangement offers the best possibility for attaching the additional components, is optimal for any radiation sensors that control the transmittance of the liquid crystal cell, and is the least disruptive to the field of view through the protective panel. Preferably, the sub-area is also arranged in or near the sagittal plane, as this corresponds to the main viewing direction and any sensors can optimally detect the radiation incident from this direction.

[0016] To achieve the aforementioned objective, an electro-optical radiation protection device comprises a frame and at least one protective screen according to a preceding paragraph, which is secured within this frame or integrally formed therewith. The frame provides mechanical protection for the sensitive edges of the protective screen and also provides stability. Furthermore, additional components and / or retaining arrangements for securing the protective device can be attached to the frame.

[0017] Another embodiment of an electro-optical radiation protection device according to the invention also comprises a frame and at least one protective screen attached to this frame or formed integrally therewith, but now additionally comprising control electronics and / or at least one radiation sensor positioned within the lower transmittance portion of the protective screen and attached to the frame or integrated therein. Due to the generally high stability of the frame and the greater freedom in positioning the additional modules, larger modules with more functionality, higher energy absorption and / or power supply duration, or a larger number of sensors can be used, which also expands the areas of application of the radiation protection device.

[0018] The radiation sensors of the frame also preferably have their highest sensitivity in the range between 400 and 1100 nm. The highest sensitivity is preferably in the infrared range from 780 nm. At the same time, the partial area of ​​the protective screen, in particular the areas at the location of the sensors, preferably has the highest transmittance in this wavelength range.

[0019] Here, too, an embodiment of the invention is preferred in which the radiation sensors attached to the frame and arranged so as to overlap with the protective screen, and preferably also the control electronics arranged in a similar manner, are arranged adjacent to the upper edge of the cover screen. This arrangement offers the best possibility for attaching the additional components, is optimal for any radiation sensors that control the transmittance of the liquid crystal cell, and is the least disruptive with regard to the field of view through the protective screen. Preferably, these elements are arranged in or near the sagittal plane of the radiation protection device. This corresponds to the main viewing direction, so that any sensors can optimally detect the radiation incident from this direction.

[0020] An advantageous embodiment of a radiation protection device according to the invention further provides that the frame is part of a support frame for the or each protective screen, which frame has at least one retaining element for holding the protective device on a person's head, in particular a temple, headband, or the like. This allows the protective device to be designed as glasses, sunglasses, welding goggles, sports or ski goggles, or the like.

[0021] It is advantageous if a protective screen extending across the entire width of the radiation protection device and, in the case of a frame encompassing the or each protective screen at the lower edge, this frame also has a nose recess in the region of the sagittal plane or the central axis of the radiation protection device forming an axis of symmetry. This recess extends from the lower edge and extends over part of the height of the protective screen(s) toward the upper edge of the frame. This results in the typical goggle contour with the best possible hold and maximum wearing comfort. Another alternative embodiment of the invention provides that the frame is part of a helmet with at least one inserted protective screen, which at least partially covers a person's head and can preferably be fixed to the head by means of at least one retaining element. This enables the protective device to be designed as a welding helmet, sports or ski helmet, or the like.

[0022] In the context of this application, a "radiation protection device" is understood to mean, in particular, a device intended to protect a user's eyes from, in particular, disturbing, light or solar radiation. Preferably, this is understood to mean, in particular, a device intended to at least reduce solar radiation. Particularly preferably, the radiation protection device is intended, in at least one operating state, to darken, in particular, disturbing, light or solar radiation on the user's eyes. Various embodiments of this device that would appear appropriate to a person skilled in the art are conceivable, such as, for example, a shield and / or, particularly preferably, protective goggles.

[0023] Furthermore, in this context, a "protective screen" is to be understood in particular as a screen made of glass and / or plastic. Its light transmittance is preferably adjustable, possibly with automatic and / or manually adjustable darkening. Particularly preferably, the protective screen has at least one liquid crystal layer with switchable transmission and at least one liquid crystal cell. Various liquid crystal cells are conceivable that would be appropriate to a person skilled in the art, such as, in particular, a TN liquid crystal cell using twisted nematic technology.Furthermore, various radiation sensors that would appear appropriate to a person skilled in the art are conceivable for a radiation protection device according to the application, for example, photocells, in particular photodiodes and / or solar cells, which are preferably designed for at least optical detection of a limited spectral range of the incident radiation and / or artificial light. The sensor surface is preferably directed forward, i.e., in particular, toward a hypothetical line of sight of a user.

[0024] The darkening or change in the transmission of the protective device should be carried out in such a way that at least 50%, preferably at least 70% and particularly preferably at least 90% of a corresponding incident radiation is absorbed and / or reflected, at least in the range of visible light, ie in particular in the wavelength range from 380 nm to 780 nm.

[0025] "Control electronics" is understood to mean, in particular, a unit with at least one electronic circuit, preferably consisting of voltage and comparison control modules. In principle, however, the control electronics can also be constructed in a more complex manner, for example by using an application-specific integrated circuit (ASIC) and / or a microcontroller module.

[0026] For a better understanding of the invention, it is explained in more detail using the following figures.

[0027] They show in a highly simplified, schematic representation:

[0028] Fig. 1 shows a first embodiment of a protective screen according to the invention with a partial area with reduced transmittance in the front view, ie from the direction of the incident radiation;

[0029] Fig. 2 the protective screen of Fig. 1 in a view obliquely from above, with the cover screen partially cut away;

[0030] Fig. 3 is a section parallel to the transverse plane in the central region of the protective screen of Fig. 1 and Fig. 2;

[0031] Fig. 4 is a perspective view of an embodiment of a radiation protection device according to the invention in the form of glasses with a protective screen corresponding to Figs. 1 to 3;

[0032] Fig. 5 shows a section parallel to the sagittal plane through another embodiment of the radiation protection device;

[0033] Fig. 6 shows a section parallel to the sagittal plane through another embodiment of the radiation protection device;

[0034] Fig. 7 shows a view of a film with two regions of different transmittance; Fig. 8 shows a view of a housing made of material with lower transmittance and integrated radiation sensors;

[0035] Fig. 9 shows a cross section through the housing of Fig. 8.

[0036] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations, whereby the disclosures contained in the entire description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and if the position changes, these positional information must be applied analogously to the new position. For a better understanding of the structure, some elements may be shown not to scale and / or enlarged and / or reduced in size.

[0037] Figure 1 shows a protective screen S for an electro-optical radiation protection device, in particular for a protective device against excessive light irradiation, for example, for use as sun protection, as sports or sunglasses, or even for self-darkening optical glasses. The use of the protective screen S in welding helmets or similar protective devices is also possible. The protective screen S covers at least the field of vision of one of the wearer's eyes and contains or supports the electro-optical element, or can itself be designed as an electro-optical element.

[0038] The protective screen S preferably consists of a cover screen 1 made of a plastic material adapted to the intended use, ideally shatter-resistant, such as polycarbonate, or of glass. The protective screen S or the cover screen 1 can itself be provided with a supporting structure, such as eyeglass temples, elastic bands, etc., to enable use as a standalone radiation protection device.

[0039] The protective screen S preferably carries on the inside, i.e. facing the wearer or on the side to be protected from radiation, at least one liquid crystal element 2 with at least one, preferably with several liquid crystal cells, as can be seen in Fig. 2, in which an upper region of the attachment screen 1 is cut away. The liquid crystal element 2 can be arranged on the attachment screen 1 in the direction of the line of sight to an object on the front or back thereof. When the sun protection device is in use, the front side faces the user of the radiation protection device, while the outside is on the opposite side facing the object to be viewed. The liquid crystal element 2 can also be an integral part of the protective screen S or attached to the outside of the attachment screen 1.The liquid crystal cells of the liquid crystal element 2 are preferably each formed from a plastic liquid crystal cell. The liquid crystal cells can each consist of several layers and can also follow the shape of the cover plate 1 with regard to the flat design as well as any curved shape. Preferably, the protective plate S is brightened in the activated state of the liquid crystal element 2 and darkened in the deactivated state.

[0040] A very advantageous embodiment provides the liquid crystal cells of the liquid crystal element 2 in a mirror-symmetrical arrangement with respect to the sagittal plane (SE). A mirror-symmetrical arrangement of liquid crystal cells with respect to a transverse plane also has advantages, for example, in facilitating a different darkening of the protective device depending on the angle of incidence of the radiation relative to the horizontal. The liquid crystal cells 2 each have a liquid crystal plane whose transmission is switchable. In principle, however, it would also be conceivable for only one liquid crystal cell to be present, which extends, in particular, across the field of vision of both eyes of the user.

[0041] As symbolized by hatching in Fig. 1, a partial area 3 of the surface of the cover plate 1 is provided, preferably at the upper edge in the middle, i.e. in the region of the sagittal plane SE (see Fig. 2), which has a permanently lower and preferably constant transmittance, i.e. is darker, than the remaining area of ​​the surface of the cover plate 1, at least when not darkened. The transmittance of the partial area 3 preferably corresponds to the lowest possible transmittance of the liquid crystal element 2 and thus of the protective plate S. Another alternative is a completely opaque or black design of the partial area 3 of the protective plate S that is impermeable to the radiation to be shielded. A coating, for example a thin layer of gold, can be provided on the cover plate 1 and / or the liquid crystal element 2 for heating the protective plate S in order to prevent or reduce fogging.An additional heating device would also be suitable for this purpose. As further symbolized in Fig. 1 by the dashed line representing the upper edge of the liquid crystal element 2, this has a cutout 4 at the location and of essentially the size of the partial region 3 of the cover plate 1 with a lower transmittance. As can be seen in Fig. 2 and Fig. 3, in this cutout 4 and thus within the partial region 3, for example, at least one radiation sensor 5 or an arrangement of several radiation sensors 5 and / or the control electronics 6 for the liquid crystal element 2 can be arranged and preferably fixed adjacent to the rear side of the cover plate 1, as shown in Fig. 5. For fixation and protection against mechanical stress, dirt and moisture, the radiation sensors 5 and / or the control electronics 6 can be encapsulated or enclosed in a potting compound.

[0042] At least one electrical contact element 7 of the liquid crystal element 2 is guided into the partial region 3 in order to establish electrical contact with the radiation sensors 5 and / or the control electronics 6. Preferably, contact elements 7 are guided from both sides of the cutout 4 into the free space of the cutout 4 located in front of or behind the partial region 3. Otherwise, no adhesives or the like, in particular no optically clear adhesives (OCA) and / or no polarizer, are provided in the contact area. However, the interface between the liquid crystal element 2 and the cover panel 1 can be colored, for example, by a colored coating, colored printing, or a thin colored frame.

[0043] Not only can a trough-shaped cutout 4 be provided in the liquid crystal element 2 when viewed from the front or rear, but alternatively or additionally, the cover plate 1 could also be made thinner in each surface area corresponding to the partial area 3 with a lower transmittance than in the remaining area, as shown in Fig. 6. Thus, with an essentially congruent liquid crystal element 2, an insertion area could be formed between the cover plate 1 and the liquid crystal element 2, into which the control electronics 6 and / or the at least one radiation sensor 5 can be inserted. These elements can be fixed in the insertion area and mechanically protected, preferably by gluing or potting.In this case, either at least one of the side walls of the insertion area can be provided with a coating made of a material with a lower transmittance, or a support structure for the inserted control electronics 6 and / or the at least one radiation sensor 5 can be provided made of a material with a lower transmittance. The partial area 3 with a lower transmittance is preferably formed by a layer 8 of a material with a lower and preferably constant transmittance applied to the cover plate 1. If there is no cutout in the liquid crystal element 2, this layer 8 is located between the cover plate 1 and the liquid crystal element 2, embedded in the form of a sandwich arrangement between these components. A preferred method for applying the layer 8 is printing the cover plate 1 with an opaque or dark printing compound.Since the cover plate 1, and thus typically the entire protective plate S, is curved at least about a vertical axis, preferably away from the frontal plane of the protective plate S, pad printing is preferably used. This printing method allows the three-dimensional shape of the partial area 3 to be coated precisely and evenly with the material intended for the layer 8. It is also conceivable to apply the layer 8 to the outer front side of the cover plate 1, i.e. on the side of the protective plate 8 facing the incident radiation. However, all methods can be used which result in a reduction in the degree of transmission, i.e. any type of coating, coating or laser treatment.

[0044] The layer 8 for achieving the lower transmittance of the partial area 3 could also be a plastic film that is glued or welded onto the cover plate 3 and / or the liquid crystal element 2, if the latter does not have a cutout 4. This film could also simultaneously serve as a carrier for the control electronics 6 and / or the or each radiation sensor 5, thereby fixing them to the protective plate S. The film could preferably completely enclose the aforementioned components, similar to an envelope, be hermetically sealed, and thus protect the components against contamination, moisture, and mechanical stress. Further alternative possibilities for applying the layer 8 are the injection molding of a material with a low transmittance onto the cover plate 1 or a co-extrusion of the material of the cover plate 1 and the material for the partial area 3. A further embodiment

[0045] A preferred embodiment of the subregion 3 with lower transmittance provides for a further subdivision of this region 3. Thus, it can itself consist of at least two subregions 3a, 3b, which have different, but both preferably constant, transmittances and consist of layers 8, 9 of different thicknesses and / or different materials. Fig. 7 shows an example of a pre-cut or pre-punched film as layer 8 with lower transmittance and layer 9 with higher transmittance, for application to the cover panel 1 and / or the liquid crystal element 2.

[0046] This allows, for example, the transmittance in front of each radiation sensor 5 to be higher than that adjacent to it, so that the radiation sensor 5's effectiveness is not overly impaired. Alternatively or in addition to this design of the layers 8, 9, the sub-regions 3a and 3b can also have different spectral transmission characteristics. For example, it is possible to allow transmission in the sub-region 3b only for that wavelength range of radiation in which the radiation sensor 5 located behind it has its highest sensitivity, or to permit transmission to such an extent that this radiation sensor 5 still delivers sufficiently strong signals to the control electronics 6, so that the latter controls the liquid crystal element 2 as desired.It is also possible to keep the sensor surfaces of the radiation sensors 5 completely free and thus allow any incoming radiation to pass through, or to design the layer 9 with higher transmission or with a range of different spectral transmission characteristics matched to the spectral sensitivity of the radiation sensors 5.

[0047] In the surrounding sub-region 3a, which may only contain components of the control electronics 6 or the contacts 7, the transmission of layer 8 can be kept significantly lower and even approach zero. For example, radiation sensors 5 are often used whose highest sensitivity is preferably in the infrared range, but in any case in the range between 400 and 1100 nm. In this case, for the sub-region 3, or at least for the sub-region 3b in the area of ​​the radiation sensor 5, a material is selected for the layer 8 or 9 there whose spectral transmission characteristics are optimized for this wavelength range. The material of layers 8 and 9 is preferably selected or designed such that visible light is at least largely blocked.

[0048] As already mentioned above, and as can be seen in Figs. 2 and 3, the control electronics 6 are positioned within the sub-area 3 with the lower transmittance and, in this specific embodiment, are fixed to the cover panel 1, for example, glued or welded thereto, or screwed or fastened by press or snap connections. In particular, the control electronics 6 are typically located in the sub-area 3a with the very low transmittance. The radiation sensors 5 are also preferably fixed to the cover panel 1 in this embodiment of the protective panel S, whereby the same connection methods can be used.

[0049] Fig. 8 and Fig. 9 show a further embodiment for producing a partial area with a lower transmittance in the protective pane S. The control electronics 6 and / or the radiation sensors 5 are accommodated in a housing 13 which is made of a material with a low transmittance. This complete assembly comprising the housing 13, the control electronics 6 and at least one radiation sensor 5 can be fixed to the cover pane 1 or the liquid crystal element 2 by any desired connection method, preferably also replaceably, and thereby forms the partial area 3 with a lower transmittance of the protective pane S. The housing 13 can also be inserted into the cutout 4 of the liquid crystal element 2 or into a slit-like or trough-like receiving space between the cover pane 1 and the liquid crystal element 2 and fixed there, now also for example by means of a potting material.

[0050] The housing 13 can be made of a material that ensures the lowest possible transmission for the radiation to be shielded, but can have a better, higher transmittance in the spectral sensitivity range of the radiation sensors 5. Such an effect can also be achieved by at least one housing section 14 made of material with a higher transmittance, which is arranged in front of the sensors 5. The housing 13 can consist of several parts that are joined together using suitable connection methods, but it can also be formed in one piece, with a hinged or elastically deflectable cover that can be locked, for example, by means of a snap closure 15, as shown in Fig. 9.

[0051] At least one electrical contact element 7 of the liquid crystal element 2 is guided into the partial area 3 in order to establish electrical contact with the radiation sensors 5 and / or the control electronics 6. Preferably, contact elements 7 are guided from both sides of the cutout 4 into the free space of the cutout 4 located in front of or behind the partial area 3. Otherwise, no adhesives or the like, in particular no optically clear adhesives (OCA) and / or no polarizer, are provided in the contact area. However, the interface between the liquid crystal element 2 and the cover panel 1 can be colored, for example, by a colored coating, colored printing, or a thin colored frame.

[0052] Not only can a trough-shaped cutout 4 be provided in the liquid crystal element 2 when viewed from the front or rear, but alternatively or additionally, the cover plate 1 could also be made thinner in each surface area corresponding to the partial area 3 with a lower transmittance than in the remaining area, as shown in Fig. 6. Thus, with an essentially congruent liquid crystal element 2, an insertion area could be formed between the cover plate 1 and the liquid crystal element 2, into which the control electronics 6 and / or the at least one radiation sensor 5 can be inserted. These elements can be fixed in the insertion area and mechanically protected, preferably by gluing or potting.In this case, either at least one of the side walls of the insertion area can be provided with a coating of a material with a lower degree of transmission or a support structure for the inserted control electronics 6 and / or the at least one radiation sensor 5 can be provided by a material with a lower degree of transmission.

[0053] Fig. 4, Fig. 5, and Fig. 6 show an exemplary embodiment of a radiation protection device according to the invention in the form of sunglasses. The protective screen S is inserted into a frame 10 and fixed therein in a possibly replaceable manner. This is particularly easy to achieve with a frame 10 that is open at the bottom and is connected or connectable to the protective screen S only in the area of ​​the upper edge of the protective screen S, at most up to the lateral area of ​​the frame 10. The frame 10 can also hold the protective screen S only at the lower edge, surround it on all sides, or only in certain sections of the peripheral edge.

[0054] A one-piece design is also conceivable, in which the frame 10 is an integral component of the protective screen S, in particular of the cover screen 1. In the case of the radiation protection device in the form of glasses, the frame 10 is part of a complete support frame, which also has the typical temples 11 of glasses, a headband that preferably elastically surrounds the head, or other conventional fastening means.

[0055] The embodiment with a frame 10 around the protective screen S also allows a construction of the radiation protection device in which the protective screen S consists only of the cover screen 1 with the partial area 3 with lower transmittance and the contacts 7 to the control electronics 6 and / or radiation sensors 5. The control electronics 6 and the radiation sensors 5 are attached directly or indirectly via support structures to the frame 10 or integrated therein, but are arranged such that they are positioned within the partial area 3 with lower transmittance of the protective screen S. The radiation sensors 5 and preferably also the control electronics 6 are also arranged in a frame 10 adjacent to the upper edge of the cover screen 1 and preferably in or near the sagittal plane of the radiation protection device (see Fig. 2).

[0056] These radiation sensors 5 also preferably have their highest sensitivity in the infrared range from 780 nm or at least in the range between 400 and 1100 nm. If sub-regions 3b are present with a higher transmittance or different spectral transmission characteristic than that of the sub-region 3 in general or the sub-region 3a, an aligned arrangement of the radiation sensor 5 and the sub-region 3b is ensured.

[0057] As can already be seen in Fig. 1 and Fig. 2, an embodiment of the protective screen S and thus also of the radiation protection device can be designed such that the protective screen S extends over the entire width of the radiation protection device. Preferably, the protective screen S and, in the case of a frame 10 which also surrounds the or each protective screen S at the lower edge - as in Fig. 4 - this frame also preferably has, in the region of the sagittal plane SE or the central axis of the radiation protection device forming an axis of symmetry, a nose recess 12 which starts from the lower edge and extends over part of the height of the protective screen S in the direction of the upper edge of the frame 10.

[0058] Of course, an embodiment of the radiation protection device is also possible in which each eye is assigned its own protective screen S. This corresponds to the conventional form of spectacles with two separate protective screens S, which are inserted into two separate receptacles of the frame 10. Advantageously, the liquid crystal elements 2, both protective screens S, are controlled by only one common control electronics 6. However, completely independent protective screens S, each with its own radiation sensors 5 and its own control electronics 6, are also conceivable, the transmittance of which can then be controlled separately and independently of one another. Such protective screens S also have subregions 3 with a lower transmittance or other spectral transmission characteristics.

[0059] Not shown is a further embodiment of a radiation protection device according to the invention, in which the frame 10 is part of a helmet or a visor with at least one inserted protective screen S. The helmet or visor at least partially covers the head, at least in the facial area, and can preferably be fixed to the head by means of at least one retaining element or support frame. The visor can be pivotably or otherwise movably connected to a helmet or support frame.

[0060] In a further embodiment, the or each protective screen S can have at least two, but preferably three radiation sensors 5, preferably arranged in a line next to one another along or parallel to a transverse axis of the protective screen S or parallel to the width of the protective screen S. The planes of the sensor surfaces of the radiation sensors 5 can enclose an obtuse angle with one another. Each of the radiation sensors 5 generates a signal as a function of the intensity of the incident radiation, from which a control signal for the liquid crystal element 2 is determined in the control electronics 6 in order to control its transmittance and thus also the transmittance of the protective screen S or the radiation protection device as a whole as a function of the radiation intensity.The control electronics 6 are preferably designed to determine an average value from the signals of all radiation sensors 5 and to control the transmittance of the liquid crystal element 2 depending on this average value. This also attracts obliquely incident radiation in order to form an average value of the intensity of the radiation striking the protective screen S. As an alternative to the design of the control electronics 6 just described, it could also be designed to control the transmittance of the liquid crystal cell 2 depending on the highest control signal of all radiation sensors 5.

[0061] The radiation sensors 5 can be conventional sensors of a suitable design or can be implemented as photodiodes, which are preferably operated in photovoltaic mode. Thus, the output voltage or output current can be fed into the control electronics 6 as a control signal and also used to supply power to the control electronics 6 and / or the liquid crystal element 2. Should more energy be required to operate the control electronics 6 and / or the liquid crystal cells 2, additional photodiodes and / or photovoltaic elements could be provided to support or entirely assume the power supply for the control electronics 6 and / or the liquid crystal cells 2. Photovoltaic elements, such as typical solar cells, could also be used as radiation sensors 5 if they can emit a signal to the control electronics 6 that is proportional to the incident radiation intensity.

[0062] In all embodiments described above, contacting can be achieved by printed conductors and contact elements.

[0063] The control electronics 6 can be expanded with various modules and functionalities, particularly if the space available is relatively large due to positioning in the frame 10 or in a support frame. For example, modules for receiving and displaying various information could be integrated, for example, distances to objects in the field of view, the speed of the wearer of the protective device, but also general information from weather services, warning services, or the like. Such data can also come from a mobile phone transmitted via Bluetooth or a similar protocol if the electro-optical protective device is equipped with a corresponding data interface. A mobile radio module could also be integrated into the control electronics 6 or frame 10 or be present in the support frame or in the protective screen S.

[0064] The control of the liquid crystal element 2 or the retrieval of certain functions of the control electronics 6 can also be carried out by actuating elements on the protective glass S or on the frame 10 or on the support frame, at least in a supplementary or bridging manner.

[0065] The above-described embodiments show possible variants. It should be noted at this point that the invention is not limited to the specifically illustrated variants, but rather various combinations of the individual variants are also possible. This variation possibility, based on the teaching of technical action by means of the present invention, lies within the skill of the person skilled in this technical field. Reference numerals

[0066] 1 front lens

[0067] 2 liquid crystal element

[0068] 3 Partial area with low transmittance

[0069] 3a First sub-area

[0070] 3b Second sub-area

[0071] 4 Excerpt

[0072] 5 Radiation sensor

[0073] 6 Control electronics

[0074] 7 Contact element

[0075] 8 Opaque layer

[0076] 9 Opaque layer

[0077] 10 frames

[0078] 11 brackets

[0079] 12 Nose recess

[0080] 13 Housing made of material with low transmittance

[0081] 14 Housing section made of material with higher transmittance

[0082] 15 snap fastener

[0083] F Frontal plane

[0084] SE sagittal plane

[0085] V Vertical axis

Claims

Patent claims 1. Electro-optical protective screen (S) for a radiation protection device, in particular a light protection device, comprising a cover screen (1), preferably made of plastic material, and at least one liquid crystal element (2) with a controllable transmittance on at least one side of the cover screen (1), further comprising at least one control electronics unit (6) for the at least one liquid crystal element (2), or at least contacts (7) for connection to such control electronics unit (6), characterized in that a partial area (3) of the surface of the cover screen (1) has a permanently lower and preferably constant transmittance than the remaining area of ​​the surface of the cover screen (1).

2. Protective screen according to claim 1, characterized in that the liquid crystal element (2) has a cutout (4) at the location and of substantially the size of the partial area (3) of the cover screen (1) with lower transmittance.

3. Protective screen according to claim 1 or 2, characterized in that the partial area (3) with a lower transmittance is formed by a layer (8, 9) of a material with a lower transmittance, preferably a print, applied to the cover screen (1).

4. Protective screen according to one of claims 1 to 3, characterized in that the partial area (3) with a lower transmittance itself consists of at least two partial areas (3a, 3b) which have different and preferably constant transmittances and / or different spectral transmission characteristics.

5. Protective screen according to one of claims 1 to 4, characterized in that the control electronics (6) are positioned within the partial area (3) with a lower degree of transmission and are fixed to the additional screen (1).

6. Protective screen according to claim 4 or 5, characterized in that at least one radiation sensor (5) connected or connectable to the control electronics (6) is positioned within the partial area (3) with lower transmittance and on the Attachment pane (1) and / or the control electronics (6), preferably in those partial areas (3b) which have the highest transmittance or at least in the spectral range of their highest sensitivity.

7. Protective screen according to claim 6, characterized in that the radiation sensors (5) have their highest sensitivity and the partial area (3, 3b) has its highest transmittance in the range between 400 and 1100 nm, preferably in the infrared range.

8. Protective screen according to one of claims 1 to 7, characterized in that the partial area (3) with a lower degree of transmission is / are arranged in the area of ​​the upper edge of the additional screen (1) and preferably in or near the sagittal plane (SE).

9. Electro-optical radiation protection device, comprising a frame (10) and at least one protective screen (S) according to one of claims 1 to 8, fastened in this frame (10) or formed integrally therewith.

10. Electro-optical radiation protection device, comprising a frame (10) and at least one protective screen (S) fastened in this frame (10) or formed integrally therewith according to one of claims 1 to 4, characterized in that the control electronics (6) and / or at least one radiation sensor (5) are positioned within the partial region (3) of the protective screen (S) with a lower transmittance and are fastened to the frame (10) or integrated therein.

11. Radiation protection device according to claim 10, characterized in that the radiation sensors (5) have their highest sensitivity in the infrared range, predominantly in the range between 400 and 1100 nm.

12. Radiation protection device according to one of claims 10 or 11, characterized in that the radiation sensors (5) and preferably also the control electronics (6) are arranged adjacent to the upper edge of the cover plate (1) and preferably in or near the sagittal plane (SE) of the radiation protection device.

13. Radiation protection device according to one of claims 10 to 12, characterized in that the frame (10) is part of a support frame for the or each protective screen (S), which has at least one holding element (11) for holding the protective device on the head of a person, in particular a bracket, headband, or the like.

14. Radiation protection device according to claim 13, characterized in that a protective screen (S) extending over the entire width of the radiation protection device and, in the case of a frame (10) also enclosing the or each protective screen (S) at the lower edge, this frame also has, in the region of the sagittal plane (SE) or the central axis of the radiation protection device forming an axis of symmetry, a nose recess (12) starting from the lower edge and extending over part of the height of the protective screen(s) (S) in the direction of the upper edge of the frame (10).

15. Radiation protection device according to one of claims 10 to 14, characterized in that the frame (10) is part of a helmet with at least one inserted protective screen (S), which at least partially covers the head of a person and can preferably be fixed to the head by means of at least one holding element.

Images