Thomson Tubes Electroniques

Synelec Telecom Multimedia

Daniel Gibilini

Bernard Courtan

The invention concerns a rear projection screen, comprising a support ( ) with focusing elements such as microlenses ( ) or lenticular elements, a holographic diffuser, and an opaque layer ( ) with apertures ( ) for allowing through the light focused by the microlenses. The light projected from the rear of the screen is concentrated by the microlenses ( ) and passes through the opaque layer by the apertures ( ). The holographic diffuser controls the directivity of the light. The incident light on the screen is absorbed by the opaque layer, such that the layer provides good transmittivity, high contrast, and controlled directivity owing to the holographic diffuser. The invention also concerns a method for making such a rear projection screen whereby the apertures in the opaque layer are formed by irradiating said layer or a preparatory material through the microlenses.

Projection screen

A high-efficiency cathodoluminescent screen for high-luminance cathode-ray tubes has a design which makes possible a considerable improvement of the luminance. The cathodoluminescent screen of the invention includes a glass substrate (11) carrying a luminescent screen (12) consisting of luminophor grains. According to a characteristic of the invention, an intermediate screen (15) is inserted between luminescent screen (12) and substrate (11), with the intermediate screen (15) having a refraction index n1 which is clearly greater than refraction index n0 of substrate (11). As a result of this arrangement, a considerable part of the light which penetrates intermediate layer (15) is reflected in the direction of luminescent layer (12), so that this light can then be rediffused to substrate (11), i.e., to use, with an emission indicatrix which is much more greatly concentrated on the axis than in the prior art.

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Saint Martin d'Uriage, France

Daniel Gibilini