| 摘要 |
A television receiver or video monitor of the back-projection type, in which a projector forms an image which can be observed on a visual display screen by rear illumination after reflection on a deflecting mirror. The projector includes in immediate proximity to the visual display screen and parallel to the latter, a reflection-transmission screen comprising a Fresnel surface, the projector, reflection-transmission screen and deflecting mirror being configured together to form an optical system such that the reflection-transmission screen reflects the rays directly emanating from the projector in the direction of the deflecting mirror and transmits these rays after their reflection on this deflecting mirror. The Fresnel surface includes striations of triangular cross-section, these striations locally forming prisms and capable of reflecting the rays which strike them when the angle of incidence of the rays are greater than a predetermined value and of transmitting the rays in an opposite case.
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