EP0285224A2
Expired / Lapsed
EP
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Colour cathode ray tube
Assignee: Koninklijke Philips NV
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Filing: 1988-03-30
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Granted: —
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Expires: 2008-03-30
Abstract
Abstract A colour cathode ray tube of the shadow mask or beam index type in which the screen structure applied to the faceplate (10) comprises a plurality of triplets of optical interference filter stripes (22) which are adapted to pass red (R), green (G) and blue (B) light produced by a homogeneous cathodoluminescent screen layer (24). The usual aluminium layer (26) may be applied to the screen layer (24). The optical interference filter stripes (22) may comprise short wave pass filters, band pass filters or a combination of both types. The short wave pass filter stripes may comprise modified quarter wavelength multi-layer dielectric filters and the bandpass filter may comprise a Fabry-Perot filter.
Inventors
- 👤 Leendert Vriens
- 👤 Johannes Cornelius Norbertus Rijpers
- 👤 Albert Adolf Comberg
- 👤 Johannes Henricus Maria Wilting
- 👤 Aart Adrianus Van Gorkum
- 👤 Franciscus Antonius Vollenbroek
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 08:40
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/18; H01J29/86; H01J29/89; H01J29/898; H01J2229/00; H01J2229/89; H01J2229/8913; H01J2229/8916
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
45 words
A colour cathode ray tube comprising an envelope having a faceplate, an optical interference filter on the internal surface of the faceplate and a cathodoluminescent layer covering the interference filter, characterised in that the optical interference filter comprises contiguous areas having different optical pass bands.
Claim 2
Dependent Claim
45 words
A colour cathode ray tube comprising an envelope having a faceplate, an optical interference filter on the internal surface of the faceplate and a cathodoluminescent layer covering the interference filter, characterised in that the optical interference filter comprises contiguous areas having different optical pass bands.
Claim 3
Dependent Claim
60 words
A cathode ray tube as claimed in claim 1, characterised in that the optical interference filter comprises a Fabry-Perot filter comprising one or more stacks of substantially quarter-wavelength thick layers having a half wavelength thick layer therein, the thickness of the half wavelength layer varying in a striped manner to optimise the pass band of the filter for different colours.
Claim 4
Dependent Claim
27 words
A cathode ray tube as claimed in claim 1, characterised in that the optical interference filter comprises contiguously arranged stripe-like modified quarter wavelength multi-layer dielectric filter elements.
Claim 5
Dependent Claim
59 words
A cathode ray tube as claimed in claim 3, characterised in that the optical interference filter is adapted to pass red, green and blue light produced by the cathodoluminescent layer, in that the filter elements for blue and green light respectively comprise short wave pass filters and in that the filter elements for red light comprise band pass filters.
Claim 6
Dependent Claim
60 words
A cathode ray tube as claimed in claim 3, characterised in that the optical interference filter is adapted to pass red, green and blue light produced by the cathodoluminescent layer, in that the filter elements for the blue light comprise short wave pass filters and in that the filter elements for green and red light respectively comprise band pass filters.
Claim 7
Dependent Claim
22 words
A cathode ray tube as claimed in claim 4 or 5, characterised in that the band pass filter elements comprise Fabry-Perot filters.
Claim 8
Dependent Claim
97 words
A cathode ray tube as claimed in claim 4, 5 or 6, characterised in that the short wave pass filters comprise between 6 and 30 layers each having an optical thickness nd , wherein n is the refractive index of the material of the layer and d is the thickness, said optical thickness nd being between 0.2λ f and 0.3λ f , in which λ f is equal to p x λ, where λ is the desired central wavelength selected from the spectrum emitted by the luminescent material and p is a number between 1.18 and 1.36.
Claim 9
Dependent Claim
23 words
A cathode ray tube as claimed in claim 7, characterized in that the short wave pass filters comprise between 10 and 20 layers.
Claim 10
Dependent Claim
26 words
A cathode ray tube as claimed in any one of claims 1 to 8, characterised in that the cathodoluminescent layer comprises a homogeneous broadband luminescent material.
Claim 11
Dependent Claim
30 words
A cathode ray tube as claimed in any one of claims 1 to 8, characterised in that the cathodoluminescent layer comprises a plurality of triplets of different colour emitting stripes.
Claim 12
Dependent Claim
34 words
A cathode ray tube as claimed in claim 10, characterised in that said contiguous areas comprise stripes and in that the colour emitting stripes extend parallel to said stripes of the optical interference filter.
Claim 13
Dependent Claim
24 words
A cathode ray tube as claimed in claim 9, characterised in that said contiguous areas comprise stripes which extend in the line scanning direction.
Claim 14
Dependent Claim
26 words
A cathode ray tube as claimed in any one of claims 9 to 12, characterised in that an aluminium layer is provided on the cathodoluminescent layer.
Claim 15
Dependent Claim
31 words
A cathode ray tube as claimed in claim 13, characterised in that a colour selection electrode (or shadow mask) is provided within the envelope adjacent to, but spaced from, the faceplate.
Claim 16
Dependent Claim
54 words
A cathode ray tube as claimed in claim 13, when appended to claim 11, characterised in that index signal emitting strips are provided on the aluminium layer, said index signal emitting strips extending substantially parallel to the strips of the optical interference filter, and in that means are provided for detecting the index signals.
Claim 17
Dependent Claim
39 words
A cathode ray tube as claimed in claim 12, characterised in that indicia are provided on the marginal area of the faceplate for producing signals indicative of the position of at least one electron beam scanning the cathodoluminescent layer.
Claim 18
Dependent Claim
22 words
A cathode ray tube as claimed in claim 14, characterised in that a single beam electron gun is provided within the envelope.
Claim 19
Dependent Claim
30 words
A cathode ray tube as claimed in any one of claims 1 to 16, characterised in that means are provided within the envelope for producing a plurality of electron beams.
Claim 20
Dependent Claim
20 words
A cathode ray tube as claimed in claim 18, characterised in that said means comprise an array of p-n emitters.
Claim 21
Dependent Claim
24 words
A colour cathode ray tube constructed and arranged to operate substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Claim 22
Dependent Claim
24 words
A colour cathode ray tube constructed and arranged to operate substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
References Cited (Backward Citations)
No citation records indexed.
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