DE7227494U - SCREEN FOR PROJECTION PURPOSES - Google Patents

Description

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LIMITED LIABILITY

Screen wall for Pro3 ek1 »i © ns purposes

The invention relates to a screen for a? Irojektions ^ purposes consisting of a reflective and a transparent film, which are laminated to each other, wherein the light transmitting sheet at which is provided the Projektionslioht to a facing surface with the Abstrahlcharakteriatlk determining structure,

Screen walls for projection purposes, which consist of several films glued together, are known, in which case, in addition to the film provided with an aluminum layer, for example, the film above it facing the projection light is translucent and consists of a suitable plastic material, for example PVC. In addition to projecting images in cinema theaters, efforts are being made to make screen walls more and more usable for daylight projection, especially for audiovisual technology. «In order to be able to carry out real daylight projection, this type of screen requires good reflective properties paired with a relatively broad radiation pattern _# Achieved This is known from the fact that on the polish side provided with an aluminum layer, an overlying transparent film is bonded with a suitable transparent adhesive, the surface of the transparent film being exposed to the projection light with a transparent

711749412,10172

provoking StruBta ^ z> B _'# a fine Mattierj | ngy saponification is. -υώ *% 8ρρΜ ^ ηΜΜ ^ € οαί ergjSfoen ^ that, despite the good reflection properties of the reflective aluminum, the abetral angle of the "screen usually does not exceed 30 °, whereby the beam angle is related to the BiMvmndnoxmale"

The purpose of the invention is one of several layers of film Kaehierte screen for projection purposes, in particular for To create daylight projection that also for a larger one Betraohterkrels all demands of modern audiovisual Projection technology is sufficient *

The object of the invention is, by means of diffusely scattering and light-refracting optical components, with good central brightness a broad radiation character at least between 35 ° and 43 ° from the normal of the screen . to achieve the projection light in the auditorium »

The invention solves the problem in the catfish that the reflective Foil in the casino plane with a diffusely reflective one Aluminum layer and the translucent layer above it Foil is provided with defined “translucent, all-round raster elements” Q * measure of Invention are subject to the as pyramids, cones, plano-convex and / or plano-concave lenses designed the following mathematical condition i

T "'/ ^ eIn {-ι ·)« · 4ηΑ Z ' Ä * * ^: wHjfc "* i. ♦> ^ wlmi'jL}

- ■■ ·> ■

Here mean: η = refractive index of the grid film,

a projection light angle of incidence on the screen,

a effective wedge angle of the grid elements, ■ * beam angle.

The advantages resulting from the invention are an extraordinarily good central brightness and a large radiation angle, so that a bright and high-contrast image impression is conveyed to a large group of viewers from every seat. The good central brightness is achieved in that, unlike known devices, the projection light is only scattered once. In the case of the known laminated picture walls made up of several foils, the projection light has to pass three times through the diffusely scattering = surface of the cover foil due to the diffuse grid structure of the surface of the transparent cover foil, which results in a considerable decrease in the middle density *. The defined "translucent and all-round limited grid elements provided according to the invention on the surface of the transparent film are regularly shaped and only slightly broadened." Significant weakening of the raster elements that determine the radiation characteristics. Another advantage of the invention is that the screen can be used for linearly polarized projection, 00 that stereo projection is also possible.

According to one embodiment, the screen is for projection purposes shown in section drawn and described below ".

As a carrier of the "reflective and translucent films serves a flexible or rigid base 1, for example made of PVC coated paper or fabric. Carrier 1 is provided with a projection light that reflects Foil 2 connected, which in the facing the projection light Level with a diffusely reflective aluminum

Layer 2 is provided ,, The aluminum layer side 2 forms at the same time the lamination level, which is achieved by gluing with a known transparent adhesive that is not described in detail the permanent connection of the reflective film 2 with a transparent film 3 arranged above it.

The surface of the transparent film 3 facing the projection light is provided with many small, defined, translucent, all-round delimited grid elements 3 ', Z _- B ₄ , pyramids, cones, plano-convex or plano-concave lenses. The shape of the grid elements is calculated so that they are subject to the following condition:

ρ ρ

sin (+) = sin 2 η - sin (+) - sin C +) cos

. A uniform screen brightness for the viewer from an optical point of view, even with large screen walls, their width over 1 m is to be guaranteed, the »invention provides that laminated shoulds 2 and 3 to connect with a curved support, the center of curvature in the projection center lies. The curvature of the screen can be variably adjusted according to the projection conditions.

Claims (7)

Expectations 1. Screen for projecting purposes, consisting of a reflective and a translucent film, which are laminated with each other, the translucent film * on the surface facing the projection light is provided with a structure that determines the radiation characteristics, characterized in that the reflecting film (2) in the lamination level is provided with a diffusely reflecting aluminum layer (2) and the transparent film (3) arranged above it is provided with defined, transparent, all-round limited grid elements (3 ¹ ), 2, screen according to claim 1, characterized in that the Grid elements are pyramids, cones, plano-convex or plano-concave lenses, the calculation of which is subject to the following condition subject to: a ( ) a sin - sin (+) - sin (+) cos Here mean »η Refractive index of the grid film, Angle of incidence of projection light on the screen, effective wedge angle of the grid element e, Beam angle. 722749412.10.72 3 · Screen according to claim. 1, characterized in that the transparent grid film (3) made of thermoplastic material and the reflective film (2) a Aluminum foil is « 4 · screen according to claim 1, characterized in that the laminated foils (2 and 3) with a flexible or rigid base or, with a flexible or rigid Carrier (1) are connected- 5. Screen according to claim 4, characterized in that the flexible base (1) made of PVC-coated paper or tissue. 6. Screen according to claim 1, characterized in that the laminated foils (2 and 3) with a curved one Beams are connected whose center of curvature lies in the Pro ^ elrtionszentrum. 7. Screen according to claim 6, characterized in that the curvature of the screen can be variably adjusted according to the projection conditions. 722749412.10.72