Abstract: Device for projecting television pictures by means of an assembly of three television picture tubes with associated lens systems arranged in each other's proximity, including an integrated cooling system. The integrated cooling system has a liquid circuit comprising a first duct extending below the television picture tubes, which duct is in direct communication via passages with the lower ends of the flow spaces, and a second duct extending above the television picture tubes, which duct is in direct communication via passages with the upper ends of the flow spaces. The first and the second duct are connected via at least one connection duct which extends along an end the assembly constituted by the three television picture tubes.

Abstract: A projection television display tube comprising an evacuated envelope (1) having a display window (4) which on its inside has a display screen (5) and in front of which on its outside a transparent second window (6) is provided, a cooling liquid (16) flowing through a space (7) between the display window and the second window from at least one inlet aperture (19) to at least one outlet aperture (17), said space communicating with an expansion vessel. The expansion vessel in the operating condition of the tube is present on the top side of the space and is a gas-filled rigid chamber (20), providing effective compensation for the thermal expansion of the cooling liquid (16) without the flow of cooling liquid being obstructed.

Abstract: Projection television display tubes having an evacuated envelope (1) with a display window (4) which on its inside comprises a display screen (5) and in front of which a light permeable second window (6) is provided on its outside, a cooling liquid (16) flowing through the space (7) between the display window (4) and the second window (6) from at least one inlet aperture to at least one outlet aperture (17) namely by temperature differences in said cooling liquid. When in such a projection television display tube at the area of the windows (4, 6) and around the said space (7) a cooling jacket (8) is provided which comprises at least one duct (9) which transports the cooling liquid (6) from the outlet aperture(s) to the inlet aperture(s) of the said space, an effective cooling is obtained at a power between 12 and 25-30 W without external pipes or a heat exchanger.

Abstract: The vertical viewing angle of a rear projection screen having a large horizontal viewing angle and good color correction due to the special shape of the light dispersing elements provided on the front side of the plate is increased by elements provided on the rear side and extending in a direction perpendicular to the front side elements. The latter are preferably total internal reflection elements, while the former are not. A bulk diffusor may be largely or completely dispensed with.

Abstract: Disclosed is a method and apparatus for recording information on a disc-shaped record carrier body with a single beam of radiation. The record carrier body is provided with a servo track which preferably exhibits a phase structure and which contains a multitude of sector addresses each associated with a portion provided with a radiation sensitive layer. Before the information is recorded, the beam is switched to a low, read level and the desired address is located. Simultaneously, the radial position and tangential speed of the radiation spot and the focusing of the radiation beam are checked. Once the desired address is located, the beam is switched to a higher, write intensity and the information is recorded on the radiation sensitive layer of the portion associated with that address. During recording, the radiation returning from the record carrier can be used to check whether the information is recorded correctly.