Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K2/00—Non-electric light sources using luminescence; Light sources using electrochemiluminescence

Definitions

• the present invention relates to long afterglow and / or fluorescent objects, predominantly long afterglow and / or fluorescent surfaces, layers or coatings with high luminance and directional light emission, a method for increasing the luminance of a long afterglow and / or fluorescent object and the use of a object according to the invention as a security marking.
• Long afterglow and / or fluorescent safety markings are used to identify escape routes and escape routes as well as to identify safety-relevant devices on escape routes and escape routes so that they can still be recognized even in the event of light failure.
• the phosphorescence luminance and the size of the phosphorescent surface are decisive for the perceptibility of long afterglow and / or fluorescent security markings in the event of sudden power failure and absolute darkness. More recently, long afterglow and / or fluorescent security markings have become to a much greater extent due to more recent developments both on the part of the phosphorescent phosphors and in the manufacture and design of long afterglow and / or fluorescent security markings which are used in the form of signs, plates, foils and molded parts in various areas used as classic emergency lighting systems.
• the luminance is particularly decisive for the recognizability of a long-afterglow and / or fluorescent safety product.
• the luminance is influenced by the quality of the phosphor, by the amount of phosphor occupied, expressed in g / m 2 , by the type and color of the substrate, the transparency of the medium in which the phosphor is embedded, such as a varnish or a polymer, and from processing.
• the luminance in the application naturally depends very much on the existing ambient lighting, ie on the type of light and the amount of light. While white and cool white light from fluorescent lamps charges the afterglow and / or fluorescent products very quickly, warm white or red light is suitable to a much lesser extent.
• the terms "cold white” and “warm white” are used here according to the standard values for color coordinates and color temperature of the American National Standards Institute (standard C78.376). Warm white or red light is essentially emitted by incandescent or fluorescent lamps of the color "warm tone".
• the existing lighting system contains all types of light and At the same time it can be expected that the lighting level is very low.
• Lx corresponds to a unit of illuminance as a quotient of luminous flux and emitting area
• the luminance of a long-afterglow and / or fluorescent marking is independent of the angle ⁇ between the surface normal and the direction of observation and always has a constant value Bo
• the present invention now provides, according to claim 1, a long afterglow and / or fluorescent article which has at least one long afterglow or fluorescent phosphor or a mixture of two or more thereof and emits light in a directed manner, i.e. the light is emitted in a preferred direction, for example perpendicular to the surface of the light-emitting object.
• the long-afterglow and / or fluorescent object is provided with an interference filter.
• an interference filter With the aid of a suitable interference filter, it is possible to achieve light bundling in a preferred direction perpendicular to the light-emitting surface and thus initially to significantly increase the light intensity dl ( ⁇ ) in this direction ⁇ and thus also the luminance B o in this direction.
• the light is emitted at angles between 0 ° and 180 ° to the emitting surface of the marking.
• an interference filter appropriately on the radiating surface of the marking, the luminance orthogonal to the surface can be increased compared to conventional long-afterglow and / or fluorescent security markings.
• the angle ⁇ at which light is emitted can be restricted to a smaller angular range and at the same time light that would otherwise have been emitted outside this angular range can be reflected in this limited angular range.
• the luminance B o of the surface is significantly increased in this preferred direction ⁇ .
• the interference filter is in the form of a film which is applied to the surface of the light-emitting object. This embodiment is advantageous in terms of its production because the application of a film is relatively quick and easy to carry out.
• the interference filter can also consist of a combination of several foils.
• the interference filter can also correspond to one or more layers vapor-deposited on a suitable substrate.
• the carrier layer itself represents an interference filter when e.g. B. the phosphor is screen printed onto the back of the interference film.
• the long-afterglow and / or fluorescent object according to the invention has at least one phosphor. Depending on the chosen phosphor, the duration of the afterglow or the fluorescence varies.
• Examples include: Phosphors as described, for example, in Ullmanns Encyklopadie der Technischen Chemie, 4th edition, volume 16, p. 179 ff. (1975), for example those based on sulfides, such as, for example, CaS: Bi, CaSrS: Bi, ZnS: Cu and ZnCdS: Cu.
• alkaline earth aluminates activated with europium or lead, the alkaline earth metal being strontium or a mixture of strontium and calcium, e.g. described in EP-A 0 094 132 and US 3,294,699 (Sr aluminate / Europium), likewise alkaline earth aluminates activated by europium, with barium and strontium as alkaline earth metals, as described in DE-A 1 811 732;
• Phosphors comprising a matrix of the formula M ⁇ . x Al 2 O. x , where M is at least one metal selected from Ca, Sr and Ba, and X is an integer other than 0, and the matrix Eu as activator and as co-activator at least one from La, Ce, Pr, Nd, Sm, Gd Contains, Tb, Dy, Ho, Er, Tm, Yb, Lu, Mn, Sn and Bi, as described in EP-A 0 710 709;
• Phosphors comprising a composition MO ⁇ a (Al ⁇ -bB) 2 ⁇ 3 : cR, where 0.5 ⁇ a ⁇ 10.0, 0.0001 ⁇ b ⁇ 0.5 and 0.0001 ⁇ c ⁇ 0.2, MO represents at least one divalent metal oxide selected from MgO, CaO, SrO and ZnO, and R represents Eu and at least one additional rare earth element, as described in DE-A 195 21 119;
• Phosphors comprising a matrix with the formal MAl 2 O 4 , where M is calcium, strontium or barium and the matrix europium as an activator and as a co- Activator contains at least one of lanthanum, cerium, preseodymium, neodymium, samarium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, tin and bismuth, as described in EP-B 0 622 440; Europium activated ternary metal oxides containing SrO or BaO or mixtures thereof, Al 2 O 3 or a mixture of Al 2 O 3 and Ga 2 O 3 and ZnO or MgO, as described in US Pat. No. 4,216,408;
• Phosphors based on an alkaline earth metal aluminate are preferably used, in particular the phosphors described in EP-B 0 622 440, EP-A 0 710 709, DE-A 195 21 119 and US 5,376,303.
• Phosphors based on SrAl O 4 : Eu, Dy or ZnS: Cu phosphors are preferably used here.
• Examples include those commercially available under the brand name "LUMILUX ® Long Afterglow Pigments", namely LUMILUX ® Green SN-CR, LUMILUX ® Green SN-C, LUMILUX ® Green SN-FOG, LUMILUX ® Green SN-F2, LUMILUX ® Green SN -S, LUMILUX ® Green N 5, LUMILUX ® Green N-PM, LUMILUX ® Green NN, LUMILUX ® Green N2, LUMILUX ® MB Green SN, LUMILUX ® Green NM 33 or also known as "LUMILUX ® Effect Pigments""are available, for example LUMILUX ® Effect Blue N, LUMILUX ® Blue Green SN, LUMILUX ® Blue Green SN-F,
• phosphors can also be used, such as, for example, UN-excitable, that is fluorescent, phosphors.
• UN-excitable that is fluorescent, phosphors.
• lamp phosphors that are commercially available under the name "LUMILUX ® Q-Pigments", namely under the brand names LUMILUX ® Red QYN, LUMILUX ® Red QYO, LUMILUX ® Red QG, LUMILUX ® Blue QCW.
• inorganic coding pigments with the Brand name "LUMILUX ® C-Pigments" can be used.
• the amount of the phosphor used is not particularly limited.
• the assignment for ZnS phosphors is preferably in a range from 300 g / m 2 to 400 g / m 2 , for phosphors based on SrAl 2 O 4 in a range from 30 g / m 2 to 300 g / m 2 .
• the object according to the invention has at least the following elements: a) a carrier layer, b) at least one long-afterglow and / or fluorescent layer arranged above the carrier layer, c) at least one interference filter arranged above the long-afterglow and or fluorescent layer.
• the interference filter is transparent to green light radiated perpendicularly and almost perpendicularly to the filter, while light which falls on the interference filter at a different angle is reflected by the interference filter.
• a non-green phosphor can also be used.
• the light that is emitted by the at least one long afterglow and / or fluorescent layer arranged above the carrier layer in the direction of the interference filter only passes the filter when it hits the filter at an angle of 90 ° or only slightly different. Light rays that strike the interference filter at a substantially smaller angle are reflected by the filter and fall back onto the long-afterglow and / or fluorescent layer. There are several options for the reflected light rays.
• the light rays can be absorbed by a phosphor particle and later emitted again by this phosphor particle, or else the light rays strike a second crystal and are reflected by it directly in the direction of the interference filter.
• the light rays reflected back by the interference filter after renewed absorption within the long afterglow and / or fluorescent layer or after renewed reflection within this layer, again in the direction Interference filter to be emitted.
• the luminance is thus increased perpendicular to the interference filter and, at the same time, the light intensity emitted laterally is reduced.
• the luminance observable perpendicular to the interference filter is accordingly increased to the disadvantage of the luminance observable laterally to the interference filter.
• the object according to the invention has, in addition to the layers listed above, further layers, for example a UV protective layer or a protective layer to reduce the flammability.
• a diffusely reflecting layer is preferably also located between the carrier layer and the phosphor layer. This ensures that no light beam emitted by the long afterglow and / or fluorescent layer in the direction opposite to the direction of the interference filter is lost, but is at least reflected back into the long afterglow or fluorescent layer and thus has the possibility, be it through direct passage through the long afterglow and / or fluorescent layer or by being absorbed again with subsequent re-emission or by one or more reflections within the long afterglow and / or fluorescent layer in the direction of the interference filter.
• the carrier layer itself consists of a diffusely reflecting, white material.
• a coated metal sheet or a metal foil is preferably used here. Aluminum is particularly preferred, but other metals can also be used.
• the carrier layer, preferably the metal sheet can have a further layer comprising an enamel. Enamel serves as embedding material for the phosphor particles.
• the long-afterglow and / or fluorescent layer has at least one phosphorescent phosphor.
• the support is made of glass, quartz glass or a transparent polymer and the fluorescent layer comprises a UV phosphor.
• UV radiation is preferably emitted from behind, i.e. radiated through the transparent support onto the fluorescent layer.
• the long-afterglow and / or fluorescent layer containing the at least one phosphor has, in addition to the phosphorescent or fluorescent phosphor, further substances, such as binders or fillers.
• binders or fillers for example, polymers such as PVC, white pigments such as TiO 2 , UV absorbers, flame retardants and / or screen printing binders are used here.
• the invention also relates to the use of the object according to the invention as a security marking.
• the long afterglow or the fluorescence and the increased luminance in a preferred direction of the object according to the invention offers considerable advantages when marking escape routes in order to make them recognizable even in the event of light failure.
• an inventive security marking or an inventive one Item contain additional prints with a non-phosphorescent color.
• the invention also relates to a method for increasing the luminance of a long-afterglow and / or fluorescent object, the method comprising at least the following step: a) arranging at least one interference filter on the long-afterglow and / or fluorescent object.
• FIG. 1 shows a schematic structure of an embodiment of an object according to the invention
• Fig. 2 plot of the afterglow density in mcd / m 2 of Examples 1 (solid line) and 2 (dashed line) against the time in minutes;
• FIG. 3 plot of the afterglow density in mcd / m 2 of Examples 3 (solid line) and 4 (dashed line) against the time in minutes.
• Figure 1 shows the schematic structure of an embodiment of an object according to the invention or a security marking according to the invention.
• the object G according to the invention has three layers A, B and C in the present embodiment.
• Layer A represents the carrier layer.
• this carrier layer A consists in a preferred embodiment of a diffusely reflecting material. This can prevent that any light beam emitted by or passing through the long afterglow and / or fluorescent layer B is absorbed in the carrier layer A and is therefore lost.
• a long afterglow and or fluorescent layer B having phosphor crystals B ′ is applied to this carrier layer A and emits light in the direction of the interference filter C. The light that strikes the interference filter at an angle of 90 ° or only slightly different can pass through the interference filter, such as the light rays 2 to 4 shown here.
• the reflected light rays are therefore not lost, but they have the possibility of being emitted again in the direction of the interference filter C after a renewed absorption and subsequent emission or after a repeated reflection. Depending on the angle at which they meet the interference filter C, they can then either pass through it unhindered or they are again reflected back in the direction of the long-afterglow and / or fluorescent layer B. This increases the luminance perpendicular to the interference filter C and at the same time reduces the intensity of the light emitted from the side. Examples
• Example 1 In Example 1, a plate of polyvinyl chloride coated with long-afterglow and / or fluorescent copper-doped zinc sulfide was provided with a commercially available interference film (Optical Lighting Film from 3M) and measured by light technology, ie the luminance in mcd / m 2 was measured determined for different times. The results obtained are shown in Figure 2 as a solid line and in Table 1, row 1.
• Optical Lighting Film from 3M
• Example 2 the long-afterglow and / or fluorescent plate from Example 1 without interference filter was also measured by means of light, analogously to Example 1, which is shown in FIG. 2 as a broken line and in Table 1, row 2.
• Example 3 a plate of aluminum coated with europium and dysprosium-doped strontium aluminate was provided with an interference filter (Optical Lighting Film from 3M) and was also measured by light technology analogously to Examples 1 and 2. The results obtained are shown in Figure 3 as a solid line and in Table 1, row 3.
• Example 4 Optical Lighting Film from 3M
• Example 3 For comparison purposes, the long-afterglow and / or fluorescent plate of Example 3 was again measured by light technology without an interference filter.
• Example 5 a plate of polyvinyl chloride coated with long-afterglow and / or fluorescent copper-doped zinc sulfide was provided with a commercially available interference film (Brightness Enhancement Film from 3M, type BEF II 100/31) and measured by light technology, ie the luminance in mcd / m 2 determined after a different length of time. The results are shown in Table 1, Row 5.
• Example 6 one with long afterglow and / or fluorescent was
• Copper-doped zinc sulfide-coated plate made of polyvinyl chloride is provided with a commercially available interference film (Brightness Enhancement Film from 3M, type BEF II 90/50) and measured by photometric means, ie. H. the luminance in mcd / m was determined after a different length of time. The results are shown in Table 1, Row 6.
• Example 7 a plate of polyvinyl chloride coated with long-afterglow and / or fluorescent copper-doped zinc sulfide was coated with a commercially available interference film (Brightaess Enhancement Film from 3M, type TRAF II) and measured using lighting technology, ie the luminance in mcd / m 2 was determined after a different period of time. The results are shown in Table 1, Row 7.
• the long-afterglow and / or fluorescent plate of Examples 5 to 7 was measured using an optical filter without an interference filter.
• Example 9 a plate made of aluminum coated with long-afterglow and / or fluorescent strontium aluminate doped with europium and dysprosium was provided with a commercially available interference film (Brightness Enhancement Film from 3M, type BEF II 100/31) and measured by lighting technology, ie it was measured Luminance in mcd / m 2 determined after a different length of time. The results are shown in Table 1, Row 9.
• a plate made of aluminum coated with long-afterglow and / or fluorescent strontium aluminate doped with europium and dysprosium was coated with a commercially available interference film (brightness
• Enhancement film from 3M, type BEF II 90/50) and lighting technology measured ie the luminance in mcd / m 2 was determined after a different length of time. The results are shown in Table 1, Row 10.
• Example 11 a plate made of aluminum coated with long-afterglow and / or fluorescent strontium aluminate doped with europium and dysprosium was provided with a commercially available interference film (Brightness Enhancement Film from 3M, type TRAF II) and measured by light technology, i. H. the luminance in mcd / m was determined after a different length of time. The results are shown in Table 1, Row 11.
• Example 12 For comparison purposes, the long-afterglow and / or fluorescent plate of Examples 9 to 11 was measured without an interference filter using light technology.
• Example 13 In Example 13, the long-afterglow and / or fluorescent plate of Example 5 was measured at an angle of 60 ° using lighting technology.
• Example 14 In Example 14, the long afterglow and / or fluorescent plate of Example 6 was measured at an angle of 60 ° using lighting technology.
• Example 15 In Example 14, the long afterglow and / or fluorescent plate of Example 6 was measured at an angle of 60 ° using lighting technology.
• Example 15 the long-afterglow and or fluorescent plate of Example 7 was measured at an angle of 60 ° using lighting technology.
• Example 16 the long-afterglow and or fluorescent plate of Example 8 was measured at an angle of 60 ° using lighting technology.
• Example 17 the afterglow and / or fluorescent plate of Example 9 was measured at an angle of 60 ° using lighting technology.
• Example 18 the long-afterglow and / or fluorescent plate of Example 10 was measured at an angle of 60 ° using lighting technology.
• Example 19 the long-afterglow and / or fluorescent plate of Example 11 was measured at an angle of 60 ° using lighting technology.
• Example 20
• Example 20 the long-afterglow and / or fluorescent plate of Example 12 was measured at an angle of 60 ° using lighting technology.

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• General Engineering & Computer Science (AREA)
• Luminescent Compositions (AREA)

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• 2000
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  • 2000-06-06 WO PCT/EP2000/005180 patent/WO2000077443A1/de not_active Ceased
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