Browse Prior Art Database

Layered Phosphor Color Cathode Ray Tube

IP.com Disclosure Number: IPCOM000090148D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Koelsch, AC: AUTHOR [+2]

Abstract

One method of providing color selection in the operation of a cathode ray tube involves the use of a two-layer phosphor in which one color or another dominates according to the anode voltage applied to the tube.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Layered Phosphor Color Cathode Ray Tube

One method of providing color selection in the operation of a cathode ray tube involves the use of a two-layer phosphor in which one color or another dominates according to the anode voltage applied to the tube.

The luminance versus anode voltage curves illustrate the operating characteristics of certain red and green phosphors. If the anode voltage applied is relatively low such as at VR, then the red color dominates. If the anode voltage is switched to above the value of a crossover of the curves such as VG, the green color dominates. Since the tube is operated at low anode voltage for red dominance, the red luminance is correspondingly low. Moreover, since color selection involves switching of the anode voltage, it is necessary to provide electronic correction of the focus and deflection circuits to compensate for differences in display size resulting from differences in electron beam energy.

The cathode ray tube structure has a plurality of anode connections V1, V2, and V3. Thus flexibility is introduced into the anode field pattern for reducing or eliminating the problems associated with such a system.

Cathode ray tube 10 has face plate 12 with a layered screen structure deposited in its inner surface. Transparent conductive coating 14 connects to anode terminal V3. A layer of green phosphor 16 overlies layer 14. Over this is another conductive transparent coating 18, connected to anode terminal V2, a layer of red phosphor 20, and a final transparent conductive coating 22 conne...