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.

A projection-type television having a movable reflective mirror provides a simple structure having a pleasing external appearance. A reflective mirror for reflecting images is movably installed on a guider so as to be moved back and forth by the guider in a perpendicular direction with respect to a screen on which the images are displayed.

A rear projection television set is disclosed which includes a screen assembly, a reflector mirror located behind the screen assembly, and a projection source having a lens system for projecting rays of light to a rear side of the screen assembly through the reflector mirror. The projection source is arranged below the reflector mirror. A ray of light emitted along an optical axis of the lens system of the projection source is reflected by the reflector mirror. A positional relationship among the screen assembly, the projection source and the reflector mirror is determined so that the reflected ray of light is incidental from an upper side to a lower side relative to the screen.

In a rear projector with a housing on whose front side is arranged a screen for displaying a video picture, with a brightness-modulated and color-modulated R-G-B light source for emitting a light bundle, with a deflecting device for scanning this light bundle, wherein the light bundle is deflected by the deflecting device over a total angle .alpha. with respect to vertical scanning, and with a deflecting mirror which is located in the housing and arranged at an angle .delta., wherein the light bundle exiting from a real or virtual vertex of the total deflection angle .alpha. is deflected onto the screen by the deflecting mirror, the virtual or real vertex located in front of the deflecting mirror lies at a location where the smallest angle .beta. of the light bundle to the surface of the screen during deflection is less than 20.degree. and the angle .delta. is given by ##EQU1##

A projection type image display apparatus having an image display element outputting an image ray, a projection lens apparatus for performing overhead projection of the image ray from the image display element, the projection lens apparatus having a plurality of lens elements, a reflection mirror reflecting the image ray from the projection lens apparatus, and a screen on which the image ray reflected by the reflection mirror is projected. An optical axis of the projection lens apparatus is decentered from a center of the screen.