Electric lamp and discharge devices – Cathode ray tube – Envelope
Reexamination Certificate
2000-02-02
2001-10-30
Cariaso, Alan (Department: 2875)
Electric lamp and discharge devices
Cathode ray tube
Envelope
C313S482000, C313S4770HC
Reexamination Certificate
active
06310435
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a cathode ray tube comprising an envelope having a conical portion, a high-voltage contact, a resilient strip having a longitudinal direction and first and second end portions which are detachably secured to the high-voltage contact inside the envelope, the first end portion comprising a getter cup, said envelope having at least one protrusion on its internal side.
A cathode ray tube having a protrusion on the internal side of its envelope is disclosed in DE-U 7726914. The cathode ray tube according to the prior art comprises a high-voltage contact to which a resilient strip is detachably secured. A cup, which contains a getter material, is mounted at one end of the resilient strip. In a certain phase of the manufacturing process of the cathode ray tube, the resilient strip is secured to the anode contact. At a later stage, the getter material is heated, which causes the getter material to evaporate. Finally, after cooling, the tube is internally covered with a thin layer of getter material ensuring that proper vacuum conditions are maintained within the tube.
The resilient strip is detachably secured to the anode contact and may rotate freely around the high-voltage contact. If no precautions are taken, there will be a risk that the resilient strip might become rotated with respect to its initial position during further processing. Then, the dispositioned resilient strip with the getter cup might cause a getter layer at the wrong location within the tube or might result in non-uniformity of the deposited getter layer. Consequently, the vacuum conditions within the tube may not meet the quality requirements, which will lead to scrap. In order to prevent dispositioning, the envelope of the cathode ray tube according to the prior art internally comprises a protrusion near the getter cup. A resilient metal w-shaped element, which engages the protrusion, is mounted on the getter cap. The getter engagement according to the prior art has the disadvantage that the specific location of the protrusion near the getter cup may affect the quality and uniformity of the layer.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a cathode ray tube in which the above disadvantages are reduced.
The cathode ray tube according to the invention is characterized in that the second end portion is cooperatively engaged with the protrusion for limiting lateral movements of the resilient strip. Such a cathode ray tube has the advantage that the risk of displacement of the getter cup and the resilient strip during further processing is reduced.
An embodiment of a cathode ray tube according to the invention is characterized in that the second end portion of the resilient strip is positioned between at least two protrusions. This embodiment will further reduce the risk that the resilient strip will be displaced. In addition, this embodiment allows the correct positioning of the resilient strip, when attached to the high-voltage contact.
A preferred form of a cathode ray tube according to the invention is characterized in that the protrusion has an elongated shape which extends substantially parallel to the longitudinal direction of the resilient strip. This elongated shape allows a good alignment of the getter assembly during attachment to the high-voltage contact.
A preferred form of a cathode ray tube according to the invention is characterized in that the distance, measured in the longitudinal direction between the center of the high-voltage contact and a point halfway the protrusion, is in the range between 2.5 and 3 cm. In practice, good vacuum conditions were obtained when said distance was within the indicated range.
These and other aspects of the invention will be elucidated with reference to the embodiments described hereinafter.
REFERENCES:
patent: 4182974 (1980-01-01), Van Ijzeren
patent: 7726914 (1978-02-01), None
“Cathode-Ray Tube”, Japanese Abstract 1-124942(A) dated May 17, 1989.
“Cathode-Ray Tube”, Japanese Abstract 60-221940(A) dated Nov. 6, 1985.
“Getter Holding and Fixing Mechanism for Cathode Ray Tube”, Japanese Abstract 5-41188(A) dated Feb. 19, 1993.
“Getter Supporting/Fixing Method for Picture Tube”, Japanese Abstract 2-86034(A), dated Mar. 27, 1990.
De Oliveira, Jr. João Gonçalves
Hageluken Ben Heinz
Cariaso Alan
Sawhney Hargobind S.
U.S. Philips Corporation
LandOfFree
Cathode ray tube with getter assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cathode ray tube with getter assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cathode ray tube with getter assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2614817