Device for generating electrons, and display device
AssigneeU.S. Philips Corporation
InventorsArthur M. E. Hoeberechts, Nicolaas Lambert, Gerardus G. P. Van Gorkom
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Abstract
A planar electron-optical lens is obtained on a semiconductor cathode surface by providing an extra electrode (16) around the gate electrode (14). Dependent on the applied voltage, this configuration operates, for example, as a positive lens which supplies parallel beams without dispersion, suitable for thin, flat display devices. A large positioning tolerance is obtained due to the inherent magnification of the beam diameter in the semiconductor device, while a grid can be dispensed with.
Claims13
A device for producing an electron beam comprising a substrate supporting an insulating layer having an aperture, emission means for emitting electrons through the aperture, and beam forming means for producing an electron lens for forming the emitted electrons into said electron beam, characterized in that said beam forming means comprises:
- a. a first planar electrode substantially surrounding the aperture where the emitted electrons exit said aperture;
- and
- b. a second planar electrode substantially surrounding the first planar electrode.
A cathode ray display tube comprising a luminescent screen, a plurality of devices for producing respective electron beams, and means for deflecting the electron beams to a direction substantially parallel to the screen, each of said devices including a substrate supporting an insulating layer having an aperture, emission means for emitting electrons through the aperture, and beam forming means for producing an electron lens for forming the emitted electrons into said electron beam, characterized in that said beam forming means comprises:
- a. a first planar electrode substantially surrounding the aperture where the emitted electrons exit said aperture;
- and
- b. a second planar electrode substantially surrounding the first planar electrode.
Dependencies are inferred from the claim text.