DE3149592A1 - Back-projection screen and method for producing it - Google Patents

Abstract

In order to guarantee greater ease of production, in a back-projection screen having a lens matrix and a shutter matrix congruent therewith the shutter matrix is constructed as a surface relief, the transparent shutter openings being raised and the depressed regions being opaque. In order to produce such a back-projection screen, the lens array is copied in the projection beam path onto negative material, the negative obtained therefrom after development is copied over in contact onto a positive photoresist layer, and the latter is converted in a manner known per se into a relief. Subsequently, both the lens matrix and the shutter matrix are formed electrochemically to produce a mould. <IMAGE>

Description

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AGFA-GEVAERT AG LEVERKUSEN Camera factory Minchen Patent and licensing

CW 2603.9 PO / MO 14.12.81

51-hl, 0617C

Rear projection screen and process for its manufacture

The invention relates to a rear projection screen with a lenticular lens and an aperture grid that is congruent to this.

Such projection screens are known as "black screen" known for a long time. However, since there has been a lack of a suitable method for mass production of such projection screens, they are has not yet spread to any significant extent.

A major problem is the assignment of lens and diaphragm grids, there are already slight deviations in the order of magnitude of a few hundredths of a millimeter Cause illumination or moiré effects.

It has therefore been proposed to produce a precise fit a diaphragm matrix fixed to the screen photographic urakehr-

CW 2603.9 PO / MO

emulsion through the lenticular screen while strictly observing the to expose the intended projection geometry. Furthermore, it has already been proposed in DE-OS 25 11 390 that the aperture in a not to generate light-sensitive black layer by evaporation with high-energy laser radiation, whereby the later projection beam path is also determined.

However, the known methods are relatively time-consuming and complex and are not suitable for inexpensive mass production. It is therefore the aim of the invention to provide a projection screen of the initially nawfeen satm ^ unä fin VeffatesR m ssiftit Hirittllüfig Sü iSnlMen; bsi which the aperture grid can be manufactured in a single operation with the lenticular grid.

According to the invention this is achieved in that the aperture raster as Surface relief is formed, wherein the transparent aperture openings are raised and the recessed areas are opaque.

A particularly expedient method for producing such a projection screen consists in copying the lenticular grid in the projection beam path onto negative material, with the negative obtained therefrom after development in contact with a positive photoresist layer copied and the latter is reshaped in a known manner to a relief and that then the tools for both the lens and can also be galvanically molded for the aperture grid.

Details of the invention emerge from the subclaims and the Description, in which an exemplary embodiment is discussed below with reference to the drawing. Show it

1 shows the general structure of a projection screen with a lens grid and a diaphragm grid,

CW 2603.9 PO / MO

2a shows the generation of the negative for the aperture raster,

Fig. 2b the copying of registration marks when generating the negative for the Aperture grid,

Fig. 2c the copying of negative and registration marks in contact on a positive Layer,

3a-d different embodiments of the pin openings.

The well-known principle of the contrast-increasing lenticular projection screen, referred to as "black screen" for short, is shown in FIG.

The incident projection light 1 is generated by a correspondingly fine, spherical or cylindrical lens grid 2 focused in a plurality of associated aperture openings, while at the same time by scattering or Refraction the desired light distribution is produced in the viewing area. Since the proportion of the area of the transparent aperture areas is proportionate is small, the screen appears almost black for non-directional incident or transmitted light, which means the desired insensitivity to interfering light is achieved.

The basic principle of the screen according to the present invention consists in the design of the screen grid as a surface relief, the depressions of which are subsequently colored in a light-absorbing manner. Production takes place in a two-sided pressing or injection process, with the two tool halves being brought together with the required tolerance by means of dowel pins or other suitable devices.

CW 2603.9 PO / MO

The master or tool production takes place in the following steps!

First of all, the original lens grid is generated photochemically or mechanically in a manner known per se. This is then provided with copyable registration marks in the tape areas.

The aperture distribution is then exposed through the lens grid onto negative photographic material according to FIG. 2a. This exposure takes place in the geometry of the later projection beam path. So that the registration marks are not copied offset, they are copied onto the diaphragm negative according to FIG. 2b in the collimated beam path.

The negative is then developed and transferred to positive photoresist material in contact as shown in FIG. 2c. Because of the contact exposure, no special measures need to be taken with regard to the registration marks will.

The photoresist layer is converted into a relief in a known manner. When copying, the layer thickness and exposure are chosen so that depending on the type of later inking process for the transparent Aperture areas result in a profile height of approx. 10-15 micrometers.

The aperture grid is then galvanically molded from this. The same applies the master from the original lenticular screen.

You now have two tool halves, each assigned to one another Passport stamps. These registration marks are converted into suitable registration devices. With the two halves of the mold, the screen can be removed in one operation can be manufactured with a precise fit.

The coloring of the faceplate of the finished Baster foils can now be done Roller application and doctoring, similar to the gravure printing process, take place. A preferred color deposit in the depressions can also be passed through the choice of suitable paint systems or additional surface treatment to influence the degree of wetting. CW 2603.9 PO / MO

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It is also possible to grind the blackened surfaces, which means at the same time a matting effect is connected.

There is an additional advantage of the proposed ribbon rail system nor in the fact that additional structures can be applied at the same time or as a second exposure when exposing the diaphragm negative. Thus, the transparent screen surface can be given a certain scattering effect or with positive or negative radii of curvature according to FIGS Figures 3a, 3b and 3c equip a certain characteristic of the The projection screen.

According to FIG. 3d, the recessed areas of the screen raster can also be roughened in order to facilitate the coloring and to increase the parasitic light absorption of the screen surface.

BATH ORIGINAL
CW 2603.9 PO / MO

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Claims (7)

AGFA-GEVA £ RT AG LEVERKUSEN Camera-Werk ißnchen Patent and Licensing CW 2603.9 PO / MO 14.12.81 51-hl, 0617C Claims 1. Rückprojelctionsschirin with a lens grid and an aperture grid that is congruent to this, characterized in that the aperture grid is designed as a surface relief, the transparent aperture openings being raised and the recessed areas being opaque. 2. A method for producing a rear projection screen according to claim 1, characterized in that the lens grid is copied in the projection beam path onto negative material, that the negative obtained therefrom after development is copied in contact with a positive photoresist layer and the latter in a known manner is formed into a relief and that the tools are then galvanically & fofcfted for both Ä8ft feifliSft- A \% and Bi eteft Blinä% mäfet * fc . 3. The method according to claim 2, characterized in that »the original lens grid is provided outside of its optically effective area with registration marks which are also transferred to the negative in the collimated beam path during the projection-copying step. CW 2603.9 PO / MO BAD ORiGIMAL 4. The method according to claim 3 / characterized in that the passport marks be transferred to the molded injection molding or pressing tool as fitting devices. 5. The method according to any one of the preceding claims, characterized in, that the coloring of the panel side of the finished film by roller application and blotting of an opaque, preferably blacken color is done, 6. The method according to any one of the preceding claims, characterized in, that the face of the cover is sanded down after the paint has been applied will. 7. The method according to any one of the preceding claims, characterized in that are exposed onto in the exposure of the negative and / or in the second exposure additional structures for influencing the scattering effect of the projection screen with. In addition 3 sheets of drawings CW 2603.9 PO / MO BAD