EP0107217A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A display apparatus and a flat tube therefor
Assignee: Philips Electronics UK Ltd
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Filing: 1983-09-13
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Granted: —
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Expires: 2003-09-13
Abstract
Abstract A display apparatus including a modular type display tube (10) having a cathodoluminescent screen (16) an elongate thermionic or P-N electron emitter (22), a channel plate electron multiplier (38) and an apertured control plate (30) between the emitter (22) and the multiplier (38). The control plate (30) has a plurality of switching electrodes (34) on the side facing the emitter (22) and a set of brightness electrodes (36) on the opposite side and extending transverse to the switching electrodes (34). In order to compensate for the variations in emission from the emitters, the brightness voltage to the brightness electrodes is turned-off and the emission is measured by scanning using the switching electrodes, a correction voltage is computed and is applied together with the modulation signal in synchronism with the scanning of the switching electrodes (34). An apertured shielding plate (28) is provided to avoid the switching voltages from the switching electrodes (34) from affecting the emissions from the emitters (22).
Inventors
- 👤 James Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 20:48
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/52; H01J31/00; H01J31/08; H01J31/10; H01J31/12; H01J31/123; H01J31/125; H01J31/126
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
153 words
A display apparatus comprising a flat display tube having a cathodoluminescent screen, electron producing means, and an apertured control plate for controlling the passage of electrons ' through at least one predetermined aperture therein, characterised in that the control plate has a plurality of switching electrodes on a side facing the electron producing means, the switching electrodes in response to addressing signals controlling the passage of electrons through at least one predetermined aperture in the control plate, and has one or more brightness control electrodes on its other side by which a modulating signal and a voltage for correcting the variations in emission of the electron producing means is applied, and in that correction voltage determining means are provided for measuring the emission incident on the control plate and for determining the correction voltage to be applied to the or each brightness control electrode in synchronism with the addressing of the switching electrodes.
Claim 2
Dependent Claim
153 words
A display apparatus comprising a flat display tube having a cathodoluminescent screen, electron producing means, and an apertured control plate for controlling the passage of electrons ' through at least one predetermined aperture therein, characterised in that the control plate has a plurality of switching electrodes on a side facing the electron producing means, the switching electrodes in response to addressing signals controlling the passage of electrons through at least one predetermined aperture in the control plate, and has one or more brightness control electrodes on its other side by which a modulating signal and a voltage for correcting the variations in emission of the electron producing means is applied, and in that correction voltage determining means are provided for measuring the emission incident on the control plate and for determining the correction voltage to be applied to the or each brightness control electrode in synchronism with the addressing of the switching electrodes.
Claim 3
Dependent Claim
20 words
An apparatus as claimed in Claim 1, characterised in that the electron producing means comprise a plurality of linear emitters.
Claim 4
Dependent Claim
19 words
An apparatus as claimed in Claim 2, characterised in that each linear emitter comprises a stretched wire thermionic emitter.
Claim 5
Dependent Claim
20 words
An apparatus as claimed in Claim 3, characterised in that the stretched wire is supported at intervals along its length.
Claim 6
Dependent Claim
17 words
An apparatus as claimed in Claim 2, characterised in that each linear emitter comprises P-N emitter arrays.
Claim 7
Independent Claim
40 words
An apparatus as claimed in any one of Claims 2 to 5, characterised in that the interior of the tube is divided by partitions into a plurality of parallel modules and in that each module has a respective linear emitter.
Claim 8
Independent Claim
42 words
An apparatus as claimed in any one of Claims 1 to 6, characterised in that the electron producing means produce low current, low voltage electrons, and in that a channel plate electron multiplier is disposed between the control plate and the screen.
Claim 9
Independent Claim
48 words
An apparatus as claimed in any one of Claims 1 to 7, characterised in that an apertured electron shielding plate is disposed between the electron producing means and the control plate, the apertures in the shielding plate constituting electron beam forming means for those electrons which pass therethrough.
Claim 10
Dependent Claim
29 words
An apparatus as claimed in Claim 8, characterised in that the apertures in the shielding plate and the control plate are distributed over substantially the whole surface area thereof.
Claim 11
Dependent Claim
59 words
An apparatus as claimed in Claim 8 or 9, characterised in that the shielding plate is divided into segments extending parallel to the switching electrodes, each segment being individually addressable, and in that the switching electrodes of the control plate are formed into sections each comprising an equal number of electrodes and corresponding electrodes of each section are interconnected.
Claim 12
Dependent Claim
36 words
An apparatus as claimed in Claim 8 or 9, characterised in that the brightness electrodes are transverse to the switching electrodes and the shielding plate is segmented with the segments extending parallel to the brightness electrodes.
Claim 13
Dependent Claim
52 words
An apparatus as claimed in Claim 7 when appended to Claim 6, characterised in that the control plate and the electron multiplier have a single column of apertures per module and in that beam deflector electrodes are provided on the walls of the partitions extending between the electron multiplier and the screen.
Claim 14
Dependent Claim
58 words
A flat display tube comprising an envelope having a faceplate on which a cathodoluminescent screen is provided, a channel plate electron multiplier arranged parallel to the screen and having an input and an output face, and electron producing means for supplying electrons over an area corresponding to substantially the whole of the input face of the electron multiplier.
Claim 15
Dependent Claim
58 words
A flat display tube comprising an envelope having a faceplate on which a cathodoluminescent screen is provided, a channel plate electron multiplier arranged parallel to the screen and having an input and an output face, and electron producing means for supplying electrons over an area corresponding to substantially the whole of the input face of the electron multiplier.
Claim 16
Dependent Claim
59 words
A flat display tube as claimed in Claim 13, characterised by an apertured control plate disposed between the electron producing means and the channel plate electron multiplier, the control plate having switching electrodes on a side facing the electron producing means and brightness control electrodes extending transverse to the switching electrodes on the other side of the control plate.
Claim 17
Dependent Claim
25 words
A flat display tube as claimed in Claim 14, characterised by an apertured shielding plate disposed between the electron producing means and the control plate.
Claim 18
Dependent Claim
27 words
A flat display tube as claimed in Claim 13, 14 or 15, characterised in that the electron producing means comprise a plurality of stretched wire thermionic emitters.
Claim 19
Dependent Claim
24 words
A flat display tube as claimed in Claim 13, 14 or 15, characterised in that the electron producing means comprise P - N emitters.
References Cited (Backward Citations)
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