DE102005042220A1 - Arrangement for the back projection of radiation, method for the preparation of the arrangement and use of a rear projection medium - Google Patents

Abstract

The invention relates to an arrangement for rear projection of radiation, the arrangement having a projector (3) for generating projection radiation, a rear projection medium (1) and an infrared radiation device (8). The rear projection medium (1) is arranged such that the projection radiation strikes the rear projection medium (1) from a rear side and corresponding images can be viewed from a front side of the rear projection medium (1). The infrared radiation device (7 and / or 8) is arranged in such a way that the infrared radiation generated and / or to be received by the infrared radiation device passes through at least one irradiation area of the rear projection medium (1) onto which the projection radiation is projected. The rear projection medium (1) is light-scattering and has, at least in the irradiation area, a material which is transparent to near infrared radiation and in which a dye combination with at least a first and a second dye is distributed, the color effects of the individual dyes differing.

Description

The The invention relates to an arrangement for making radiation visible by rear projection, in particular for the production of images, a method of production the arrangement, the use of a rear projection medium and a Design of a rear projection medium.

through the rear projection technology can Information to a wide audience. in principle For example, the structure of such a system may include a rear projection medium. that from the back illuminated with a projector, with the information through Scattering in the rear projection medium becomes visible.

These Technique finds e.g. Use in control rooms (power stations, railway traffic), to the person in charge the overview of the complex processes so that control errors can be avoided. A Another application is large-scale scoreboards e.g. in sports stadiums and motorsports races. The spectators can in this way the course and the status of the event transmitted even if they are a long way from the actual one To stop events.

By permanent Further development of the projector technology are further over the years Application fields added. This is how this kind of information is transmitted also e.g. for TV sets, Open plan and Home theaters, but also as an advertising medium applied at fairs, in shop windows and shops. Furthermore becomes the rear projection technique also for the transmission of information at presentations and used in flight simulators to maximize the virtual environment realistically on the cockpit discs map.

meanwhile There are a variety of plastic sheets and films that as Rear projection medium be used. Often plates are designed so that these defined surface structures in Form of Fresnel lens systems on the back and additionally vertical arranged lenticular lenses on the observer side (front side) exhibit. However, they are also rear projection media with homogeneous optical properties and / or smooth surfaces.

It is also known, at least areas of rear projection media to increase the Color contrast gray, so that the visual content even in a bright environment the front of the rear projection medium are clearly recognizable. this leads to however, especially for rear projection media with homogeneous optical properties to an absorption of visible Radiation to be made.

One Advantage of the rear projection technology is that the projector is outside the viewing space can stand. A viewer in front of the projection screen thus does not obscure the projection, disturbing noises of the projector avoided and an attractive interior design is possible. Known gray colored Rear projection media However, they have a high degree of absorption for infrared radiation. Accordingly in applications where such, by the rear projection medium passing radiation is used, a stronger radiation source be used. Alternatively or additionally, the effort for a detection the passing infrared radiation increases and / or the functionality impaired.

Examples for applications, in which radiation in the wavelength range the near infrared is used, for example, in WO 2003/063069 (Detection of touch a disc with a finger), WO 2003/003730 (TV device with remote control using IR radiation) and US 2003/214640 A1 (Method of prevention Unauthorized recording of projected images by blending with NIR radiation).

Task and solution

It is an object of the present invention to provide an arrangement and a rear projection medium which, in the case of a bright environment, allow a high contrast of the information visualized on the medium. Furthermore, it is an object of the invention to provide a method of manufacturing the assembly, a use of a rear projection medium and an embodiment of a rear projection screen specify the date. In this case, infrared radiation should be usable at high efficiency in combination with the rear projection medium.

It becomes a back projection medium proposed that a light-scattering and permeable to near infrared radiation material having. In the light scattering, for near infrared radiation permeable material a dye combination having at least a first and a second Dye spread, resulting in color effects of the individual dyes differ.

Under Light scattering becomes a particularly visible light scattering Material understood, that is not or only partially transparent or translucent.

• – einen Projektor zur Erzeugung von Projektionsstrahlung,
• – ein Rückprojektionsmedium, das derart angeordnet ist, dass die Projektionsstrahlung von einer Rückseite auf das Rückprojektionsmedium auftrifft und entsprechende Bilder von einer Vorderseite des Rückprojektionsmediums betrachtet werden können,
• – eine Infrarotstrahlungseinrichtung, die derart angeordnet ist, dass von der Infrarotstrahlungseinrichtung erzeugte und/oder von der Infrarotstrahlungseinrichtung zu empfangende Infrarotstrahlung durch zumindest einen Bestrahlungsbereich des Rückprojektionsmediums hindurch tritt, auf den die Projektionsstrahlung projiziert wird, wobei das Rückprojektionsmedium lichtstreuend ist und zumindest in dem Bestrahlungsbereich ein für nahe Infrarotstrahlung durchlässiges Material aufweist, in dem eine Farbstoffkombination mit zumindest einem ersten und einem zweiten Farbstoff verteilt ist, wobei sich Farbwirkungen der einzelnen Farbstoffe unterscheiden.

Furthermore, an arrangement for the back projection of radiation is proposed, the arrangement comprising:

• A projector for generating projection radiation,
• A rear projection medium arranged such that the projection radiation impinges on the rear projection medium from a rear side and corresponding images can be viewed from a front side of the rear projection medium,
• An infrared radiation device arranged such that infrared radiation generated by the infrared radiation device and / or to be received by the infrared radiation device passes through at least one irradiation region of the rear projection medium onto which the projection radiation is projected, wherein the rear projection medium is light-scattering and at least in the irradiation region for permeable material near infrared radiation, in which a dye combination with at least a first and a second dye is distributed, wherein color effects of the individual dyes differ.

Embodiment of the invention

Inventive arrangements

The The invention relates to an arrangement for the back projection of radiation, the arrangement comprising:

• • a projector ( 3 ) for generating projection radiation,
• A rear projection medium ( 1 ), which is arranged such that the projection radiation from a rear side onto the rear projection medium ( 1 ) and corresponding images from a front side of the rear projection medium ( 1 ),
• An infrared radiation device ( 7 and or 8th ) arranged such that the infrared radiation device ( 8th ) and / or from the infrared radiation device ( 7 ) to receive infrared radiation by at least one irradiation region of the rear projection medium ( 1 ) is projected onto which the projection radiation is projected, wherein the rear projection medium ( 1 ) is light-scattering and at least in the irradiation region has a material which is permeable to near infrared radiation (800 to 1400 nm wavelength) in which a dye combination having at least one first and one second dye is distributed, color effects of the individual dyes differing.

The invention particularly relates to an arrangement, wherein the infrared radiation device ( 7 and or 8th ) one on the back of the rear projection medium ( 1 ) arranged detector ( 7 ) for detecting infrared radiation and wherein the arrangement is designed such that an infrared radiation, which is due to a touch of the body ( 2 ) and / or approaching an object at its front side of the rear projection medium ( 1 ) is generated, deflected, absorbed and / or reflected by the rear projection medium ( 1 ) passes through and from the detector ( 7 ) can be detected.

The invention further relates to an arrangement, wherein the infrared radiation device ( 7 ) is arranged and equipped such that natural and / or artificially generated near infrared radiation from the front through the rear projection medium ( 1 ) and from the infrared radiation device ( 7 ) on the back of the rear projection medium ( 1 ) can be detected.

The invention further relates to an arrangement, wherein the infrared radiation device ( 8th ) is arranged and configured in such a way that it generates near infrared radiation generated by it from the rear side through the rear projection medium ( 1 ), deflected at the front, absorbed and / or reflected, and from the infrared radiation device ( 7 ) on the back of the rear projection medium ( 1 ) can be detected.

In an advantageous embodiment of the arrangement, the rear projection medium, for. As the rear projection film, arranged on a rear surface of a transparent body. In this case, the projector is arranged on the back of the body beyond the rear projection medium, so that the images can be viewed from a front side of the body through the body. The invention enables such applications, wherein despite an additional possible absorption of the infrared radiation in the transparent body, a sufficiently large proportion of the infrared radiation can still pass through the rear projection medium. This makes it possible, in particular, subsequently to attach the rear projection medium to already existing bodies, wherein the rear projection medium can, for example, also be removable again. The invention accordingly relates to an arrangement in which the rear projection medium ( 1 ) on a back surface of a body permeable to light and near infrared radiation ( 2 ) and wherein the projector ( 3 ) on the back of the body ( 2 ) beyond the rear projection medium ( 1 ) is arranged so that the images from a front of the body ( 2 ) through the body ( 2 ) can be viewed through. The body can z. B. a glass plate, for. B. be a shop window, on or on the back projection medium is applied without being firmly connected or with or on this z. B. be fixed by an adhesive layer. The body can also z. B. be a plastic plate of polymethylmethacrylate or polycarbonate. In this case, if desired, a solid composite may be present with the backprojection medium in the form of a laminate or a coextrudate. In this arrangement, the body has the function of protecting the rear projection medium from damage by contact or from contamination.

The invention further relates to an arrangement in which a body permeable to light and near infrared radiation (US Pat. 2 ) between the rear projection medium ( 1 ) on the projector ( 3 ) is arranged directly on the back of the rear projection medium. The body can z. B. be a glass plate, which rests against the rear projection medium body without being firmly connected or with or on this z. B. be fixed by an adhesive layer. The body can also z. B. be a plastic plate of polymethylmethacrylate or polycarbonate. In this case, if desired, a solid composite may be present with the backprojection medium in the form of a laminate or a coextrudate. The body in this arrangement primarily has a supporting function for the rear projection medium.

Infrared radiation device

The Infrared radiation device can from an infrared source or an infrared generator and an infrared receiver or detector, However, it can alternatively only from an infrared source or a Infrared generator or an infrared receiver or detector exist.

In the simplest case, the infrared radiation device is merely a receiving device for the reception and detection of the infrared radiation (in particular the near infrared radiation). By near infrared radiation is meant a wavelength range of 800 to 1400 nm. In this case, artificial or natural near-infrared radiation (eg, infrared radiation radiated from the sun through the transmissive material) is detected by the infrared radiation device. The sun or, if appropriate, another infrared source already present in the environment is therefore used in this case as a previously existing infrared-generating device (see, for example, FIG. 4 ).

Alternatively, the infrared radiation device may merely be an infrared-generating device for generating the (in particular near) infrared radiation (see, for example, US Pat. 5 ). This variant makes it possible, for example, to prevent unauthorized image recordings of a projection projected on the rear projection medium.

A another possibility is that the infrared radiation device both the Generation device and the receiving device has.

The rear projection medium

The light-scattering and at least in the irradiation range for near infrared radiation permeable material allows passage of infrared radiation and also forms due to the Farbstoffkom a background for a high-contrast image representation or representation of other effects of the radiation to be made visible. In this case, the rear projection medium or at least one layer of the rear projection medium may consist entirely of the permeable material. Alternatively, only at least a portion of the rear projection medium is made of the permeable material. By way of example, regions other than light diffusers and / or optical lenses may be designed.

Further becomes the use of a rear projection medium for a visualizing or making detectable radiation proposed, the one from the back of the rear projection medium on the rear projection medium is projected, wherein an infrared radiation is generated and by a material of the rear projection medium is radiated through and / or through the material of the rear projection medium passing infrared radiation is detected and wherein the Rear projection medium is light scattering and one for near Infrared radiation permeable Material in which a dye combination with at least a first and a second dye is distributed, wherein Differentiate color effects of the individual dyes.

Rear projection screen

The Rear projection medium may preferably have the shape of a film. The subject belongs to the invention therefore a rear projection foil from a light-scattering and for near infrared radiation permeable Material, being in the permeable Material a dye combination with at least a first and a second dye is distributed, wherein color effects of distinguish individual dyes and wherein the rear projection foil in particular a thickness in the range up to 3 mm, preferably less than 1.5 mm, in particular 0.1 to 3 mm, 0.2 to 2.0 mm, preferably 0.3 to 1.5 mm, especially preferably 0.4 to 1.0 mm. In principle, however, can also be Rear projection medium be used with a different shape, for example, a plate-shaped rear projection medium with a thickness of more than 2 mm. Because of compared to other substances for gray coloring low concentration (in terms of area) of dyes, however, can especially thin Body, in particular the films, as rear projection media getting produced.

The Rear projection screen can also be used as a laminated or coextruded composite with a Plate made of transparent material. The transparent material can z. B. polymethyl methacrylate.

method for producing a device for rear projection

• • Bereitstellen eines Rückprojektionsmediums (1) aus einem lichtstreuenden und für nahe Infrarotstrahlung durchlässigen Material, in dem zumindest ein erster und ein zweiter Farbstoff verteilt sind, wobei sich Farbwirkungen der einzelnen Farbstoffe unterscheiden,
• • Bereitstellen eines Projektors zur Erzeugung von Projektionsstrahlung,
• • Anordnen des Rückprojektionsmedium und des Projektor derart, dass die Projektionsstrahlung von einer Rückseite auf das Rückprojektionsmedium auftrifft und entsprechende Bilder von einer Vorderseite des Rückprojektionsmediums betrachtet werden können,
• • Anordnen einer Infrarotstrahlungseinrichtung derart, dass von der Infrarotstrahlungseinrichtung erzeugte und/oder zu empfangende Infrarotstrahlung durch zumindest einen Bestrahlungsbereich des Rückprojektionsmediums hindurch tritt, auf den die Projektionsstrahlung projiziert wird, wobei das Rückprojektionsmedium zumindest in dem Bestrahlungsbereich das für nahe Infrarotstrahlung durchlässige Material aufweist.

The invention also encompasses a method for producing a device for the back projection of radiation according to one of the preceding claims, comprising the following steps:

• Providing a backprojection medium ( 1 ) of a light-scattering material which is permeable to near-infrared radiation and in which at least a first and a second dye are distributed, color effects of the individual dyes differing,
• Providing a projector for generating projection radiation,
• Arranging the rear projection medium and the projector in such a way that the projection radiation impinges on the rear projection medium from a rear side and corresponding images can be viewed from a front side of the rear projection medium,
• Arranging an infrared radiation device in such a way that infrared radiation generated and / or to be received by the infrared radiation device passes through at least one irradiation region of the rear projection medium onto which the projection radiation is projected, the rear projection medium having material permeable to near infrared radiation at least in the irradiation region.

The Visible making the radiation in the rear projection medium in particular achieved in that the radiation at least in areas of the Rear projection medium is scattered. In this case, a scattering in the permeable material and / or in other areas of the rear projection medium.

The generated by the infrared radiation device and / or to be received Infrared radiation is especially in the wavelength range of the near infrared (800 to 1400 nm wavelength). The still to be mentioned optical properties in the infrared range can especially at one or more particular wavelengths, e.g. B. 1100 nm, or in at least a portion of the near Infrared. For example, you can Control signals (eg a remote control) using the infrared radiation and / or the presence of a body (eg, fingers on one) Disc) transmitting infrared radiation through the rear projection medium be or pass through.

dye combination

Under a dye combination is basically any use of two or more, 3 or more, 4 or more dyes, in particular three or four dyes, understood, for example, a mixture the dyes that are dispersed in the permeable material. However, the individual dyes or subcombinations thereof may in an alternative procedure successively in the permeable material be distributed and / or produced in the permeable material. A dye is understood in particular to mean a product as it is commercially available is. In this case, the dye in particular from a mixture of different consist of chemical compounds.

dyes

Under Dyes with different color effects in particular Dyes understood their transmittance (for a given surface density of the respective dye) in the visible spectral range in different Way with the wavelength vary, so different from the individual dyes Color effects are achieved, for. B. red, yellow or green.

Suitable for the purposes of the invention are, for. B. red dyes from the class of perinone dyes, eg. B. the commercial product Macrolex ^® Red EC. Suitable z. B. green dyes from the class of Anthrachinonfarbstoffe, z. B. the commercial product Macrolex ^® Green EC. Suitable z. B. green or bluish violet dyes from the class of Anthrachinonfarbstoffe, z. As the commercial product Macrolex ^® green EC or the commercial product Macrolex ^® Violet 3R. Suitable z. B. yellow dyes from the class of quinophthalone dyes, z. B. the commercial product Macrolex ^® Red EC.

By the transmittance is the proportion of transmitted radiation relative to that of the back of the rear projection medium defined incident radiation. The transmission is through the Absorption and reflection are determined. For a precise description the color effect must therefore, these two effects are also indicated (i.e., the degree of absorption and the reflectance) and must not only those of the back considered incident radiation but also the incident from the front radiation. For reasonable dye concentrations in rear projection media is the Reflectance, however, low, so that the color behavior is sufficient exactly by specifying the degree of transmission or the degree of absorption can be specified.

On However, the reason for the different color effects is the overall transmittance the dye combination in the visible spectral range over the Transmittances of the individual dyes at least partially in the direction of a spectrally unselective (gray) transmittance balanced. If the dye concentration is low, can the optical properties of the dye combination easy by spectral overlay determine the optical properties of the individual dyes. For example, leads this in a preferred dye combination with a green, red, yellow and violet dye to compensate for the spectrally selective Behavior in the transmission and thus a gray "color". For larger concentrations Combination effects are added, for example by multiple reflection and possibly by modifying the optical properties due to chemical compounds of the individual dyes.

The invention is based on the finding that selected, known per se dyes have a high color effect in the visible wavelength range, but only slightly absorb in the near infrared. This is (z. B. Macrolex® ^® Red EG from Bayer) is the case even with selected red dyes. This property can be used in the dye combination to achieve an approximately constant transmission behavior by suitable mixing of individual dyes over the entire visible wavelength range, but the absorption of radiation in the near infrared is still small in the sum of the individual dyes. Surprisingly, transmittances (depending on the surface density of the dyes at a constant value, for example in the range from 0.3 to 0.85, in particular from 0.4 to 0.4) could be approximately constant (fluctuations of less than ± 10% based on the transmittance) to 0.65) in the visible wavelength range, wherein the transmittance in the near infrared at values greater than 0.6, greater than 0.7, greater than 0.8, greater than 0.85 or in the range of 0.6 to 0.93. This will be discussed in more detail by way of examples of dye combinations. The transmission and the reflection are z. B. according to DIN (German Industrial Standard) 5036 determined with a meter Lambda 19 from Perkin Elmer. The scattering power can be determined according to DIN 5036 with a measuring device LMT goniometer measuring station GO-T-1500 from LMT Lichtmesstechnik GmbH Berlin, Germany.

at an advantageous embodiment of the arrangement is the rear projection medium, z. B. the rear projection foil, at a back surface a transparent body arranged. The projector is on the back of the body beyond of the rear projection medium arranged so that the images pass through from a front of the body the body can be considered through.

The Invention allows Such applications, wherein despite an additional possible absorption of the infrared radiation in the transparent body still a big enough one Proportion of infrared radiation through the rear projection medium can occur. This allows in particular, the rear projection later already existing bodies with the rear projection medium for example, also be removable again. Preferably the surface of the rear projection medium its front is designed and tuned to the back of the body, that the rear projection medium adheres to the body without further aids (for example adhesive).

at Such an arrangement may be the infrared radiation device one on the back of the rear projection medium arranged detector for detecting infrared radiation, wherein the arrangement is designed such that an infrared radiation, the due to a touch of the body and / or approach an object at its front generates, deflects, absorbs and / or reflected by and through the body and the rear projection medium passes through, is detected by the detector. Thus, the Effect of a "touch Screen "achieved but with the actual screen (the rear projection medium) through the transparent body protected is. The body is for example a shop window.

at the arrangement with the transparent body and the rear projection medium the infrared radiation device can be arranged and configured in this way be that natural and / or artificial generated near infrared radiation from the front through the body and the rear projection medium passes, detected by the infrared radiation device can be.

alternative or additionally the infrared radiation device can be arranged and configured in such a way that generated by her near infrared radiation, from the back through the rear projection medium and the body passes.

The Dye combination is preferably selected such that for the permeable Material with the dye combination of the red-green transmission color value (with a * designated) of the CIE (Commission Internationale d'Eclariage) Lab color model in the range of -5 to 5, preferably in the range of -2.5 to 2.5 and the yellow-blue transmission color value (denoted by b *) of the CIE Lab color model in the range of -5 to 5, preferably in the range of -2.5 to 2.5.

One according to unselective (gray) behavior is for a color neutral Contrast effect of advantage.

Further is preferred that the permeable Material with the dye combination distributed in the near Infrared spectral range a transmittance of more than 0.6 preferably greater than 0.8. The transmission brightness value L * of the CIE Lab color model is z. B. over 60, especially over 70.

As dyestuffs per se known organic dyes are proposed, their concentration per dye generally in the range of 0 to 0.8 wt .-%, preferably 0.000001 to 0.4 wt .-%, based on the total weight of the colored permeable material , The sum of the dye concentrations is preferably in the range of 0 to 1 wt .-%, preferably 0.0001 to 0.6 wt .-%, based on the total weight of the colored permeable material. Suitable dyes are in particular: ^® Sandoplast Red G and Sandoplast ^® Yellow 2G each from Clariant as well as ^® Macrolex Red EG, Macrolex ^® Green 5B, Macrolex ^® Violet 3R and ^® Macrolex Yellow G each from Bayer. For example, a dye combination of the four mentioned dyes Macrolex ^® (red, green, purple and yellow) is used. The ratio of the dyes z. B. at 61: 50: 10: 1 (red: green: violet: yellow), wherein the proportion of each dye by ± 15% (based on said ratio) can be varied.

The Rear projection medium according to the invention in particular has a light-scattering layer with polymethylmethacrylate (PMMA), wherein at least portions of the layer, the dye combination and therefore cause a contrast effect for radiation emitted by the front of the layer is incident.

polymethylmethacrylate (PMMA)

polymethyl methacrylates are generally obtained by radical polymerization of mixtures, containing methyl methacrylate. In general, these include Mixtures at least 40% by weight, preferably at least 60% by weight and particularly preferably at least 80% by weight, based on the weight the monomers, methyl methacrylate. In addition, these mixtures for the production of polymethyl methacrylates contain further (meth) acrylates which be copolymerized with methyl methacrylate. The term (meth) acrylates includes methacrylates and acrylates as well as mixtures of both.

These monomers are well known. These include, but are not limited to, (meth) acrylates derived from saturated alcohols such as methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate. Pentyl (meth) acrylate and 2-ethylhexyl (meth) acrylate;
(Meth) acrylates derived from unsaturated alcohols, such as. Oleyl (meth) acrylate, 2-propynyl (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate;
Aryl (meth) acrylates, such as benzyl (meth) acrylate or phenyl (meth) acrylate, wherein the aryl radicals may each be unsubstituted or substituted up to four times;
Cycloalkyl (meth) acrylates such as 3-vinylcyclohexyl (meth) acrylate, bornyl (meth) acrylate; Hydroxyalkyl (meth) acrylates such as 3-hydroxypropyl (meth) acrylate, 3,4-dihydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate;
Glycol di (meth) acrylates such as 1,4-butanediol (meth) acrylate, (meth) acrylates of ether alcohols such as tetrahydrofurfuryl (meth) acrylate, vinyloxyethoxyethyl (meth) acrylate;
Amides and nitriles of (meth) acrylic acid, such as N- (3-dimethylaminopropyl) (meth) acrylamide, N- (diethylphosphono) (meth) acrylamide, 1-methacryloylamido-2-methyl-2-propanol;
sulfur-containing methacrylates such as ethylsulfinylethyl (meth) acrylate, 4-thiocyanatobutyl (meth) acrylate, ethylsulfonylethyl (meth) acrylate, thiocyanatomethyl (meth) acrylate, methylsulfinylmethyl (meth) acrylate, bis ((meth) acryloyloxyethyl) sulfide;
polyvalent (meth) acrylates, such as trimethyloylpropane tri (meth) acrylate.

In addition to the (meth) acrylates set out above, the compositions to be polymerized may also contain other unsaturated monomers which are copolymerizable with methyl methacrylate and the abovementioned (meth) acrylates. These include, inter alia, 1-alkenes, such as hexene-1, heptene-1;
branched alkenes such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methylpentene-1;
acrylonitrile; Vinyl esters, such as vinyl acetate; Styrene, substituted styrenes having an alkyl substituent in the side chain, such as. [Alpha] -methylstyrene and [alpha] -ethylstyrene, substituted styrenes having an alkyl substituent on the ring such as vinyltoluene and p-methylstyrene, halogenated styrenes such as monochlorostyrenes, dichlorostyrenes, tribromostyrenes and tetrabromostyrenes;
Heterocyclic vinyl compounds, such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiolane, vinylthiazoles and hydrogenated vinylthiazoles, vinyloxazoles and hydrogenated vinyloxazoles;
Vinyl and isoprenyl ethers; Maleic acid derivatives such as maleic anhydride, methylmaleic anhydride, maleimide, methylmaleimide; and
Dienes, such as divinylbenzene.

in the Generally, these comonomers are in an amount of 0 to 60 Wt .-%, preferably 0 to 40 wt .-% and particularly preferably 0 to 20 wt .-%, based on the weight of the monomers used, the compounds individually or as a mixture can be used.

The Polymerization is generally done with known radical initiators started. Among the preferred initiators include those in the Well-known azo initiators such as AIBN and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds, such as methyl ethyl ketone peroxide, acetylacetone peroxide, Dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxide, methyl isobutyl ketone peroxide, Cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane, tert -butylperoxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, Dicumyl peroxide, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, Cumyl hydroperoxide, tert-butyl hydroperoxide, Bis (4-tert-butylcyclohexyl) peroxydicarbonate, mixtures of two or more of the aforementioned compounds with each other and mixtures the aforementioned compounds with compounds not mentioned, which can also form radicals.

These Connections become common in an amount of 0.01 to 10% by weight, preferably 0.5 to 3 Wt .-%, based on the weight of the monomers used. in this connection can various poly (meth) acrylates are used, for example in molecular weight or in the monomer composition.

Other polymers

Of Furthermore, the matrix of the light-scattering layer may contain further polymers included to modify the properties. These include under Other polyacrylonitriles, polystyrenes, polyethers, polyesters, polycarbonates and polyvinyl chlorides. These polymers can be used individually or as a mixture be used, including copolymers, those of the aforementioned Polymers are derivable.

molding compounds for the preparation of the light-scattering layer can conventional additives of all kinds contain. These include including antistatics, antioxidants, mold release agents, flame retardants, lubricants, Flow improvers, fillers, Light stabilizers, UV absorbers and organic phosphorus compounds, such as phosphites or phosphonates, weathering agents and plasticizers. The amount of additives depends on the application. The If appropriate, molding composition can be produced by an impact modifier mechanically sturdier equipped become.

The Dye combination, for example, already at the beginning of the process be added to the polymerization or be. From the polymerization receives one z. B. granules.

The Rear projection medium can over known processes are produced using thermoplastic molding processes are preferred. According to one embodiment is used for extrusion or for the production of litter beads Molding granules used a twin-screw extruder. in this connection The plastic particles are preferably transferred to the melt in the extruder.

The Rear projection medium can over a two-step process can be made in which z. B. Sidefeeder compounding on a twin-screw extruder and Zwischengranulierung the extrusion of the film or plate downstream of a single-screw extruder.

Of Furthermore, a one-step process can be carried out in which by means of an extrusion die a flat Product is formed. Furthermore can the rear projection medium be produced by injection molding. Furthermore, it is in principle also possible the rear projection medium in the casting process, z. In a polymerization chamber.

Especially in a rear projection medium with homogeneous optical properties (eg without additional Diffuser) can the permeable Material with the dye combination distributed therein a light scattering power σ (measured according to DIN 5036) in the visible spectral range of more than 0.2, preferably of more than 0.3. This is done, for example, by adding light reaching scattering substances such as barium sulfate or titanium dioxide.

Alternatively, however, the rear projection medium may, for example, comprise scattering particles, the particles having a different refractive index compared to the matrix (the permeable material) containing plastic particles as scattering media. This is how the document describes JP 11179856 z. B. Multi-layer panels having at least one layer comprising a polymethyl methacrylate matrix and cross-linked polymethyl methacrylate beads as a spreading / matting agent, wherein the proportion of the beads is in the range of 0.5 to 25 wt .-%. The beads have a size in the range of 3 to 30 microns. The Japanese patent application JP 07234304 describes a mixture of cross-linked acrylate / styrene beads (14 μm) in a transparent plastic.

Like in the DE 102 51 778 A1 described can spherical plastic particles z. Example, with a particle size in the range of 5 to 35 microns in a concentration in the range of 2 to 60 wt .-% based on the total weight of the rear projection or a light-scattering layer of the rear projection medium be present. In this case, the spherical plastic particles have a refractive index difference to the matrix (for example polymethyl methacrylate matrix) in the range from 0.02 to 0.2.

following the invention will be described by way of example (particularly preferred embodiment) and two comparative examples explained in more detail, without the invention limited to the example shall be.

• – 26 Gew.-% eines perlförmigen Copolymerisat aus 55 Gew-% Methylmethacrylat, 40 Gew-% Benzylmethacrylat und 5 Gew-% Allylmethacrylat (die Streueigenschaften, insbesondere der Halbwertswinkel und das Streuvermögen der Folie werden dadurch eingestellt); dabei betrug die mittlere Teilchengröße ca. 20 µm im Durchmesser der perlförmigen Teilchen,
• – 22,5 Gew.-% METABLEN^TM IR-441 (Poly(Methylmethacrylat/Butylacrylat/Styrol), ein Schlagzähmodifizierungsmittel von Mitsubishi Rayon Co., Ltd.,
• – 0,1 Gew-% eines UV-Stabilisators, Tinuvin P (2-(2'-Hydroxy-5'-methylphenyl)-benzotriazol) von Ciba Specialty Chemicals Inc.,
• – 0,05 Gew-% eines Licht-Stabilisators (HALS-Produkt), Tinuvin 770 (Bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate von Ciba Specialty Chemicals Inc.

Two film-shaped rear projection media having a film thickness of 1 mm were prepared by extrusion. For this purpose, a granulate was used which has the following constituents:

• - 26 wt .-% of a bead-shaped copolymer of 55% by weight of methyl methacrylate, 40% by weight of benzyl methacrylate and 5% by weight of allyl methacrylate (the scattering properties, in particular the half-value and the scattering power of the film are adjusted); the mean particle size was about 20 μm in the diameter of the bead-shaped particles,
• 22.5% by weight of METABLEN ^™ IR-441 (poly (methyl methacrylate / butyl acrylate / styrene), an impact modifier from Mitsubishi Rayon Co., Ltd.,
• 0.1% by weight of a UV stabilizer, Tinuvin P (2- (2'-hydroxy-5'-methylphenyl) benzotriazole) from Ciba Specialty Chemicals Inc.,
• - 0.05% by weight of a light stabilizer (HALS product), Tinuvin 770 (bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate from Ciba Specialty Chemicals Inc.

The granules for one of the films (preferred embodiment) containing a color mixing with 0.00731% by weight Macrolex ^® Red EG, 0.00602% by weight Macrolex ^® Green 5B, 0.00116% by weight Macrolex ^® Violet 3R and 0.00012 % by weight Macrolex ^® Yellow G (both from Bayer). In the first comparative example, no dye combination was added.

The Dyes (only for the preferred film) and the ingredients enumerated above about 48.7 wt .-%. The remainder to 100% by weight of the films made respectively a polymethyl methacrylate type 7N from Röhm GmbH & Co. KG (polymer of 96% by weight) Methyl methacrylate and 4 wt .-% methyl acrylate), ie about 51.3 Wt .-% polymethylmethacrylate. The dyes were previously in a Part of the polymethylmethacrylate 7N dispersed.

The granules thus obtained formed the basis for further production the two slides. An extruder with a diameter of 60 mm was used BREYER GmbH, Singen, Germany. The temperature of the melt at the nozzle exit was in the range of 240-270 ° C. The calender became set as one as possible rough surface was achieved.

Further was a 3 mm, conventionally colored with 0.004849 wt% carbon black (Flammruß 101 from Degussa AG) thick rear projection plate from polymethyl methacrylate (manufacturer Röhm GmbH & Co. KG) optically measured. The measurement results for the three examples are given in Table 1.

Tabelle 1: Messergebnisse optischer Eigenschaften The transmission and the reflection were determined according to DIN (German Industrial Standard) 5036 with a PerkinElmer Lambda 19 meter. In this case, a radiation source of the light type D65 (sodium light) was used. The scattering power was determined according to DIN 5036 with a measuring device LMT goniometer measuring station GO-T-1500 from LMT Lichtmesstechnik GmbH Berlin, Germany.

Table 1: Measurement results of optical properties

Out Table 1 shows that the infrared transmittance at λ = 1100 nm wavelength in the preferred embodiment is not degraded by the dye combination. This is recognizable from the comparison to the comparative film without dyes. Both values are around 0.9. The slight increase in the film with Dyes is due to a different directional characteristic of the IR transmission, by a slightly lower Content of polymethyl methacrylate 7N in the granules and by light Variability in the production process can be explained.

there is the transmittance in the visible wavelength range in the film with Dyes significantly lower (0.48 compared to 0.83). This is a consequence the light absorption due to the coloring, resulting in a high contrast the light display leads in bright surroundings. The radiation flux density The projection radiation on the back should therefore be included the preferred embodiment the film higher its than the film without dyes. Also the reflectance is greater in the film without dyes.

A Color neutrality (gray or white Color behavior) in the visible wavelength range is in all three Rear projection media given as the a * and b * values of both the transmission and also the reflection is recognizable. The slightly higher b * values (over 2) of the Reflection are irrelevant in the result, since the reflectances and L * values of reflection are significantly lower.

The scattering power lies with all three rear projection media around 0.3. With regard to the scattering power, therefore, the three media are comparable.

at the film with dyes could compared to conventionally carbon black colored backprojection media be found that the visible light is in the range of + - 40 degrees against the surface normal with a higher one Luminance is transmitted when the transmitted luminance in the ranges beyond + - 40 Degrees against the surface normal about the same size for both media.

At the Comparison of the preferred embodiment to the carbon black colored medium the transmittance in the visible range is the same Magnitude. The permeability for infrared radiation in the near infrared is in the film with dyes but about twice as big.

All in all It is to be noted that when compared to the film with dyes too conventionally dyed Media a higher Luminance can be achieved. In addition, the transmittance for infrared radiation much larger in the near infrared.

in the The invention will be described below with reference to the attached drawing described. However, the invention is not limited to the case mentioned Examples limited. The same reference numerals in the figures designate the same or functionally identical Elements. In detail shows:

1 the transmittance as a function of the wavelength for the above-described films with and without dyes,

2 a first example of an arrangement according to the invention,

3 a second example of the arrangement according to the invention,

4 a third example of the inventive arrangement and

5 a fourth example with a particularly preferred embodiment of the arrangement.

1

In 1 The continuous line represents the spectral curve of the transmittance of the above-described film without dyes. The dashed line represents the spectral curve of the transmittance of the film with dyes. It can be seen that the transmittance of the film with dyes in the visible wavelength range a constant course in the Has a value of 50% and steeply increases to a value of about 89% in the transition range from the visible range to the near infrared. In contrast, the transmittance of the film without dyes has no such increase in the transition region.

2

In the 2 shown in schematic side view arrangement has a rear projection medium 1 , a transparent body for visible light 2 and a projector 3 on. The body 2 is for example a shop window and is above a floor 4 arranged. The rear projection medium 1 is on a back side (in the illustration on the right) of the body 2 arranged. Again from a back of the rear projection medium 1 can projecting radiation from the projector 3 be irradiated, wherein the projection radiation is at least predominantly in the visible wavelength range. In addition, the projection radiation for the purpose described in US 2003/0214640 A1 for the blending of image recordings radiation in the near infrared. An area irradiated by the projection radiation 5 extends from the projector 3 to the rear projection medium 1 , In the rear projection medium 1 which is preferably the above-described rear projection film having a dye combination contained therein.

The projection radiation in the visible wavelength range is in the projection medium 1 scattered, allowing a viewer from the front of the transparent body 2 (In the illustration on the left) an image corresponding to the projection radiation and / or a corresponding light distribution can be viewed.

3

3 shows an arrangement that is opposite to in 2 illustrated arrangement is modified and supplemented. The projector 3 is near the ground 4 arranged so that the irradiated area 5 not like in the case of 2 is approximately symmetrical to a perpendicular bisector of the back surface of the projection medium but asymmetrical. In addition, there is a detector 7 (Infrared radiation receiver) for the detection of infrared radiation and an arrangement of infrared radiation sources (infrared radiation generator) 8th Components of the arrangement.

The infrared radiation sources 8th are so close to the rear projection medium 1 arranged that an infrared radiation emanating from them an area at the front of the body 2 reached. Alternatively (and not only with the basis of 3 described embodiment, but in any embodiments of the inventive arrangement), an infrared radiation source or a plurality of infrared radiation sources may be located further away from the rear projection medium. For example, the respective infrared radiation source may be arranged in the vicinity of the detector or at the front of the body. It can also be dispensed with an artificial infrared radiation source and z. B. of course, existing infrared radiation from the sunlight can be used. In this case, the sun is the infrared radiation device or infrared radiation source.

Preferably, the infrared radiation sources 8th configured and arranged such that the infrared illuminance directly on the front surface of the body 2 and / or is particularly large at a small distance in front, but in other areas at the front of the body 2 is lower. In particular, the infrared illuminance falls sharply with increasing distance from the surface of the body 2 from.

In 3 is schematically a finger or pointer 6 at the front of the body 2 shown. The pointer 6 increasingly reflects with decreasing distance to the surface of the body 2 those from the infrared radiation sources 8th irradiated infrared radiation in the direction of the detector 7 as indicated by dotted lines. For example, if that of the detector 7 Detected infrared radiation reaches or exceeds a predetermined intensity threshold, detects the detector 7 the existence of the pointer 6 , Besides, the detector is 7 preferably designed so that it can determine at which point the front end of the pointer 6 the body 2 is closest to or touched him (a corresponding embodiment of the detector 7 and the infrared radiation sources 8th For example, the already mentioned publication WO 03/063069 A2 can be removed.

Due to the high permeability of the rear projection medium 1 For infrared radiation, it can be particularly well recognized where the pointer is located and whether the pointer is a certain distance to the surface of the body 2 has fallen short of or touched him. Alternatively or additionally, the intensity of the infrared radiation sources 8th Outgoing infrared radiation can be reduced. The detector 7 In particular, a corresponding evaluation unit may also have an evaluation unit for evaluating the received signals, the evaluation unit being at a distance from an IR sensor of the detector 7 can be arranged. The presentation of the 3 is to be understood purely schematically. With the reference number 7 in particular, only the location of the IR sensor can be designated.

4

4 shows an arrangement that differs from the in 3 illustrated arrangement differs in that no means for generating infrared radiation is provided as part of the arrangement. Rather, infrared radiation is used in the embodiment, which is naturally present in the environment and the example of the sun 11 is produced. The infrared radiation passes through the body 2 and the rear projection medium 1 through and hits the back of the rear projection medium 1 on the detector 7 , As indicated by the dotted lines, the finger throws 6 a shadow, so that z. B. by evaluating one of the detector signals of the detector 7 derived infrared image the position of the finger 6 can be determined.

5

5 shows a particularly preferred arrangement, compared to the in 2 illustrated arrangement is completed. It is an infrared radiation source 8th on the back of the rear projection medium 1 intended. One with the reference numeral 15 designated infrared radiation cone emanates from the infrared radiation source 8th and penetrates both the rear projection medium 1 as well as the body 2 , Due to the low absorption of the rear projection medium 1 Near infrared radiation hardly weakened the body 2 , In the example, the body is 2 also well-drained for the infrared radiation, so also on the front of the body 2 high infrared irradiances can be achieved. Therefore, it is possible, for example, similar to proposed in US 2003/214640 A1, unauthorized image recordings on the rear projection medium 1 prevent projections. Unlike in 5 shown, the infrared radiation cone 15 not only the cross-sectional area of the rear projection medium 1 It can also cover infrared radiation directly on the body 2 to meet.

Claims (13)

Arrangement for the rear projection of radiation, the arrangement comprising: - a projector ( 3 ) for generating projection radiation, - a rear projection medium ( 1 ), which is arranged such that the projection radiation from a rear side onto the rear projection medium ( 1 ) and corresponding images from a front side of the rear projection medium ( 1 ), an infrared radiation device ( 7 and or 8th ) arranged such that the infrared radiation device ( 8th ) and / or from the infrared radiation device ( 7 ) to receive infrared radiation by at least one irradiation region of the rear projection medium ( 1 ) is projected onto which the projection radiation is projected, wherein the rear projection medium ( 1 ) is light-scattering and at least in the irradiation region has a material which is permeable to near infrared radiation and in which a dye combination having at least a first and a second dye is distributed, color effects of the individual dyes differing. Arrangement according to claim 1, wherein the infrared radiation device ( 7 and or 8th ) one on the back of the rear projection medium ( 1 ) arranged detector ( 7 ) for detecting infrared radiation and wherein the arrangement is designed such that an infrared radiation, which is due to a touch of the body ( 2 ) and / or approaching an object at its front side of the rear projection medium ( 1 ) is generated, deflected, absorbed and / or reflected by the rear projection medium ( 1 ) passes through and from the detector ( 7 ) can be detected. Arrangement according to claim 1 or 2, wherein the infrared radiation device ( 7 ) is arranged and configured in such a way that natural and / or artificially generated near infrared radiation from the front side through the rear projection medium (FIG. 1 ) and from the infrared radiation device ( 7 ) on the back of the rear projection medium ( 1 ) can be detected. Arrangement according to claim 1 or 2, wherein the infrared radiation device ( 8th ) is arranged and configured in such a way that it generates near infrared radiation generated by it from the rear side through the rear projection medium ( 1 ) is deflected, deflected at the front, absorbed and / or reflected and by the infrared radiation device ( 7 ) on the back of the rear projection medium ( 1 ) can be detected. Arrangement according to one or more of claims 1 to 4, characterized in that the rear projection medium ( 1 ) on a back surface of a body permeable to light and near infrared radiation ( 2 ) and wherein the projector ( 3 ) on the back of the body ( 2 ) beyond the rear projection medium ( 1 ) is arranged so that the images from a front of the body ( 2 ) through the body ( 2 ) can be viewed through. Arrangement according to one or more of Claims 1 to 4, characterized in that a body permeable to light and near infrared radiation ( 2 ) between the rear projection medium ( 1 ) on the projector ( 3 ) is arranged directly on the back of the rear projection medium. Use of a rear projection medium ( 1 ) for visualizing radiation coming from a back side of the rear projection medium ( 1 ) on the rear projection medium ( 1 ), wherein - generates an infrared radiation and by a material of the rear projection medium ( 1 ) and / or through the material of the rear projection medium ( 1 ) infrared radiation is detected, and - wherein the rear projection medium ( 1 ) is light-scattering and has a material which is permeable to near infrared radiation and in which a dye combination having at least one first and one second dye is distributed, with color effects of the individual dyes differing. Rear projection screen from a light-scattering and for near infrared radiation permeable Material, being in the permeable Material a dye combination with at least a first and a second dye is distributed, wherein color effects of distinguish individual dyes and wherein the rear projection foil has a thickness of less than 3 mm. Rear projection screen according to claim 9, characterized in that it is laminated or coextruded composite with a sheet of transparent material is present. Arrangement, use or rear projection foil after a of the preceding claims, wherein the dye combination is selected such that for the permeable material with the dye combination of the red-green transmission color value a * of the CIE (Commission Internationale d'Eclariage) Lab color model in the field of 5 to 5, preferably in the range of -2.5 to 2.5, and the yellow-blue Transmission color value b * of the CIE-Lab color model in the range of 5 to 5, preferably in the range of -2.5 to 2.5. Arrangement, use or rear projection foil after a of the preceding claims, the permeable one Material with the dye combination distributed in the near Infrared spectral range a transmittance of more than 0.5 preferably greater than 0.7. Arrangement, use or rear projection foil after a of the preceding claims, the permeable one Material with the dye combination distributed therein a light scattering power σ (measured according to DIN 5036) in the visible spectral range of more than 0.2, preferably of more than 0.3. Method for producing a device for the back projection of radiation according to one of the preceding claims, comprising the following steps: - providing a rear projection medium ( 1 ) of a light-scattering material which is permeable to near-infrared radiation and in which at least one first and one second dye are distributed, color effects of the individual dyes differing, - provision of a projector ( 3 ) for generating projection radiation, - arranging the rear projection medium ( 1 ) and the projector ( 3 ) such that the projection radiation from a rear side onto the rear projection medium ( 1 ) and corresponding images from a front side of the rear projection medium ( 1 ), - arranging an infrared radiation device ( 7 and or 8th ) such that the infrared radiation device ( 8th ) and / or from the infrared radiation device ( 7 ) to receive infrared radiation by at least one irradiation region of the rear projection medium ( 1 ) is projected onto which the projection radiation is projected, wherein the rear projection medium ( 1 ) has the material which is permeable to near infrared radiation at least in the irradiation area.