U.S. Philips Corporation

Bernardus H Hendriks

Nicolaas Lambert

Siebe Tjerk De Zwart

Gerardus G Van Gorkom

Gerardus A Vrijssen

Petrus H Trompenaars

A scanning device for an optical record carrier (1) comprises a high-numerical aperture dual lens objective system (10, 11) for focussing a radiation beam (7) on an information layer (3) of the record carrier. The lens (11) of the objective system closest to the record carrier is tilted by a tilt servo system in response to tilt of the record carrier. The tilt angle of the lens is preferably less than the tilt angle of the record carrier in order to reduce optical aberrations of the radiation beam such as coma and astigmatism.

Device for optically scanning a record carrier

An optical device for optically scanning an information plane includes a radiation source for supplying a scanning beam, and an objective system for focusing the scanning beam to a scanning spot on the information plane. The temperature dependence of the objective system can be compensated by a compensator which includes a planoconvex first element and a planoconcave second element arranged between the radiation source and the first element, the convex surface of the first element confronting the concave surface of the second element, and the refractive indices of the first and the second element being equal at the design temperature but having a different temperature dependence.

Optical scanning device and optical apparatus for reading and/or writing

Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

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Eindhoven, Netherlands

Bernardus H Hendriks