FR2511516A1

FR2511516A1 - Portable type projector screen - consists of sheet of tracing paper between non-reflecting glass sheets

Info

Publication number: FR2511516A1
Application number: FR8115725A
Authority: FR
Inventors: Nicole Lambert
Original assignee: CUPERMAN FERNAND
Current assignee: CUPERMAN FERNAND
Priority date: 1981-08-14
Filing date: 1981-08-14
Publication date: 1983-02-18

Abstract

The portable projection screen uses tracing paper or any other sheet of diffusing plastics or organic material. This sheet is sandwiched between two non reflecting sheets of glass or other non reflective material. The inner sheet acts like a double ground face and light diffusion through the screen, either by reflection or by transmission, allows projection by both methods. The inner sheet has good transmission properties and gives a good image, whatever may be the ambient illumination.

Description

La présente invention concerne un dispositif du type "écran" destiné à l'observation par réfection ou par transparence de projection lumineuse. The present invention relates to a device of the "screen" type intended for observation by repair or by transparency of light projection.

Dans les dispositifs de ce genre, chacun est conçu pour un emploi bien déterminé; soit pour une observation de projection lumineuse par réflection, soit pour une observation de projection lumineuse par transparence et dans ce dernier cas l'écran fait le plus souvent partie intégrante d'un ensemble complet, comportant le dispositif de projection. De ce fait, il est forcément de dimensions restreintes, et la plupart du temps fragile t d'entretien difficile, la surface diffusante comportant un dépoLi externe. In devices of this kind, each is designed for a specific job; either for observation of light projection by reflection, or for observation of light projection by transparency and in the latter case the screen is most often an integral part of a complete assembly, comprising the projection device. Therefore, it is necessarily of limited dimensions, and most of the time fragile and difficult to maintain, the diffusing surface comprising an external coating.

L'écran, objet de la présente invention, permet d'éviter les ineonvénients précédemment cités parce qu'il est en effet constitué de deux plaques de verre ayant subi un traitement antireflet, ou de toute autre matière présentant les mêmes caractéristiques de transparence et ayant des propriétés antireflet, entre lesquelles est disposée soit une feuille de papier calque, soit une feuille de toute autre matiere plastique, or ganique ou vautre, présentant les neumes caractéristiques que le papier calque, l'ensemble cotant ou non scellé pour le rendre étanche et hors poussière. The screen, object of the present invention, makes it possible to avoid the aforementioned drawbacks because it is in fact made up of two glass plates having undergone an anti-reflective treatment, or of any other material having the same transparency characteristics and having anti-reflective properties, between which is placed either a sheet of tracing paper or a sheet of any other plastic material, ganic or wall, having the same characteristics as tracing paper, the whole dimensioning or not sealed to make it waterproof and dust-free.

L'ensemble des éléments composant cet écran présente les avantages suivants
- l'élément diffusant est protégé puisqu'il est intérieur
AU dispositif, il ne nécessite donc aucun entretien,
- les surfaces extérieures étant pratiquement lisses sont d'un entretien facile puisque ne comportant ni grain, ni rugo sité, ni porosité. L'encrassement est réduit au strict minimum et le nettoyage facilité.All the elements making up this screen have the following advantages
- the diffusing element is protected since it is interior
AU device, it therefore requires no maintenance,
- the exterior surfaces being practically smooth are easy to maintain since they contain no grain, roughness or porosity. Clogging is reduced to a minimum and cleaning is facilitated.

- la feuille diffusante intérieure au dispositif se comportc optiquement comme un dépoli double face operant une diffusion de la lumiere des deux cotes de l'écran, soit par transmission, soit; o i t par réflection, suivant le cas. - the diffusing sheet inside the device behaves optically as a double-sided frosted effect diffusing the light from both sides of the screen, either by transmission or; o i t by reflection, as appropriate.

-Cette craetCristieue présente l'avantage de permettre l'observation d la projection tant par réflectioXl que par transparence. -This craetCristieue has the advantage of allowing observation of the projection both by reflectioXl and by transparency.

- La très faible épaisseur de la feuille diffusante évite les phénomènes de réfraction qui généraient l'observation dans le cas de i Temploi d'un dépoli double face obtenu a partir de plaques ou de feuilles d'épaisseur nettement plus importante, en raison de la traversée par les rayons lumineux de l'espace entre ces deux dépolis,
- le tres bon indice de transmission lumineuse et l'absence presque totale de phénomene de réfraction permettent d'obtenir un iriage tres lumineuse et d'excellente définition rendant possible l'observation de la projection en éclairage ambiant relativement intense.- The very thin thickness of the diffusing sheet avoids the refraction phenomena which generated observation in the case of the use of a double-sided frosted surface obtained from plates or sheets of significantly greater thickness, due to the crossed by the light rays of the space between these two frosted areas,
- the very good index of light transmission and the almost total absence of refraction phenomenon allow to obtain a very bright iridescence and excellent definition making it possible to observe the projection in relatively intense ambient lighting.

- le comportement de cette feuille interne au dispositif comme un dépoli double face assure également une grande diffusion de la lumiere permettant une observation confortable sous des angles pouvant étire considerés comme largement obtus. - the behavior of this sheet internal to the device as a frosted double face also ensures a large diffusion of the light allowing a comfortable observation under angles which can be considered widely obtuse.

Claims

1. Portable projection screen characterized by the fact that it consists of a sheet of tracing paper or any other sheet of diffusing plastic or organic material having the same characteristics as tracing paper, a sheet sandwiched between two glass plates anti-reflective, or any other anti-reflective material having the same transparency characteristics.

2. portable projection screen according to claim nO I characterized in that the interior diffusing sheet behaves practically like a double-sided frosted, the scattering of light on both sides of the screen, either by reflection or by transmission, allows projection by transparency and by reflection.

3. portable projection screen according to claim n "1 characterized in that the internal plate has a good light transmission index which allows good qualities of transmission of the device and to observe the image with good brightness, whatever or ambient lighting.

4. portable projection screen according to claim nO I characterized in that the sheet internal to the device behaves like a frosted double face and ensures a large diffusion of light, it allows to keep a sufficiently bright vision of 1 image under a relatively large angle to the normal axis of the screen.

5. portable projection screen according to claim nO I characterized in that the translucent element is internal to the device and that the outer surfaces do not have roughness retaining dust, so that cleaning and

maintenance is facilitated.