CA1164923A - Cathode-ray tube - Google Patents
Cathode-ray tubeInfo
- Publication number
- CA1164923A CA1164923A CA000314372A CA314372A CA1164923A CA 1164923 A CA1164923 A CA 1164923A CA 000314372 A CA000314372 A CA 000314372A CA 314372 A CA314372 A CA 314372A CA 1164923 A CA1164923 A CA 1164923A
- Authority
- CA
- Canada
- Prior art keywords
- neck
- getter
- tube
- cathode
- collar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/94—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
Abstract
ABSTRACT:
A cathode-ray tube having a getter disposed in contact with a layer provided in the cone of the tube.
In order to avoid the problems of (a) having to protect the getter material when the getter is mounted in the cone early in the manufacture of the tube, (b) the getter, which is attached by a resilient metal strip to the elec-tron gun assembly, shorting-out, in the event of a flash-over, a resistive layer provided in the neck of the tube, and (c) the resilient metal strip impeding accurate posi-tioning of the electron gun assembly, the getter is mounted by way of a resilient metal strip attached to a resilient clamping member clamped in the neck between the electron-gun assembly and the neck-cone transition and in contact with the internal resistive layer. The cathode-ray tubes may be used for any desired purpose, particularly in colour television receivers.
A cathode-ray tube having a getter disposed in contact with a layer provided in the cone of the tube.
In order to avoid the problems of (a) having to protect the getter material when the getter is mounted in the cone early in the manufacture of the tube, (b) the getter, which is attached by a resilient metal strip to the elec-tron gun assembly, shorting-out, in the event of a flash-over, a resistive layer provided in the neck of the tube, and (c) the resilient metal strip impeding accurate posi-tioning of the electron gun assembly, the getter is mounted by way of a resilient metal strip attached to a resilient clamping member clamped in the neck between the electron-gun assembly and the neck-cone transition and in contact with the internal resistive layer. The cathode-ray tubes may be used for any desired purpose, particularly in colour television receivers.
Description
The invention relates to a cathode-ray tube.
A cathode-ray tube generally comprises an envelope including a neck, a cone and a window portion, an electrode system provided in the neck to generate at least one electron beam, and a getter.
A generally used method of securing a getter holder in a cathode~ray tube, for example a television display tube, is that in which the getter holder is secured to the electrode system by means of an elongate resilient metal strip (antenna) and is then inserted into the tube neck together with the electrGde system.
The metal strip is pre-bent so that the getter holder is ~ pressed against the wall of the cone. A disadvantage of :'' this method is that the metal strip is resiliently press-ing against the cone of the tube exerts a force on the electrode system, which impedes an accurate positioning and centring of the electrode system in the tube neck.
Such a connection presents problems in particular when the tube comprises a resistive layer which is provided 20~ internally on the tube wall and which extends at least from~the neck-cone transition into ~he neck. As dis-closed in British Patent Specification 1,226,728, which : : ~ : :
issued on March 31, 1971 to Philips Electronics and Associated Industries Limited, this layer serves to 25~ restrict the detrimental consequences of a possible elec-ric flash-over in the tube on the electronic circuit of the television receiver. These flash-overs mainly occur between electrodes o~f the electrode system which are situatea at a small distance from each other and which
A cathode-ray tube generally comprises an envelope including a neck, a cone and a window portion, an electrode system provided in the neck to generate at least one electron beam, and a getter.
A generally used method of securing a getter holder in a cathode~ray tube, for example a television display tube, is that in which the getter holder is secured to the electrode system by means of an elongate resilient metal strip (antenna) and is then inserted into the tube neck together with the electrGde system.
The metal strip is pre-bent so that the getter holder is ~ pressed against the wall of the cone. A disadvantage of :'' this method is that the metal strip is resiliently press-ing against the cone of the tube exerts a force on the electrode system, which impedes an accurate positioning and centring of the electrode system in the tube neck.
Such a connection presents problems in particular when the tube comprises a resistive layer which is provided 20~ internally on the tube wall and which extends at least from~the neck-cone transition into ~he neck. As dis-closed in British Patent Specification 1,226,728, which : : ~ : :
issued on March 31, 1971 to Philips Electronics and Associated Industries Limited, this layer serves to 25~ restrict the detrimental consequences of a possible elec-ric flash-over in the tube on the electronic circuit of the television receiver. These flash-overs mainly occur between electrodes o~f the electrode system which are situatea at a small distance from each other and which
2 -~..
~.~6'~3 are operated at very different potentials. In such a flash-over, a capacitor which is formed by the conductive inner and outer coatings o the cone discharges. The discharge is associated with current intensities rising very rapidly in time so that in particular semiconductor components in the electronic circuit of the television receiver can be damaged via inductive or capacitive coup-lings. The current strength occurring in such a discharge is reduced by the resistive layer so that the possibility of damage to the electronic circuit is reduced. When such a resistive layer is used in conjunction with a getter holder which is secured to the electrode system by a resilient metal connection strip, the resistive layer may -~
be short-circuited by the connection strip, and in the .
case of a possible elec~ric flash-over in the tube sliding sparks can occur along the connection strip. The endeav-oured operation of ths rssistive layer is then lost for the greater part. In order to solve this problem, British Patent Specification 1,226,728 proposes to secure the ; .
getter holder to a component which is located inside the conical part of the tube~. The securing is carried out prior to sealing the glass cone to the glass window. It is then necessary to use~a getter which can withstand the detrimental in1uence of gases and vapours during subse-quent stsps in the manufacturing process of the tube.
It is an object of the invention to secure a ~:: : : ~
getter in a cathoda-ray tube in a simple way so that there ; is no dirsct mschanical coupling between the electrode system and the securing element of the ge~ter holder.
~.~6'~3 are operated at very different potentials. In such a flash-over, a capacitor which is formed by the conductive inner and outer coatings o the cone discharges. The discharge is associated with current intensities rising very rapidly in time so that in particular semiconductor components in the electronic circuit of the television receiver can be damaged via inductive or capacitive coup-lings. The current strength occurring in such a discharge is reduced by the resistive layer so that the possibility of damage to the electronic circuit is reduced. When such a resistive layer is used in conjunction with a getter holder which is secured to the electrode system by a resilient metal connection strip, the resistive layer may -~
be short-circuited by the connection strip, and in the .
case of a possible elec~ric flash-over in the tube sliding sparks can occur along the connection strip. The endeav-oured operation of ths rssistive layer is then lost for the greater part. In order to solve this problem, British Patent Specification 1,226,728 proposes to secure the ; .
getter holder to a component which is located inside the conical part of the tube~. The securing is carried out prior to sealing the glass cone to the glass window. It is then necessary to use~a getter which can withstand the detrimental in1uence of gases and vapours during subse-quent stsps in the manufacturing process of the tube.
It is an object of the invention to secure a ~:: : : ~
getter in a cathoda-ray tube in a simple way so that there ; is no dirsct mschanical coupling between the electrode system and the securing element of the ge~ter holder.
-3-~:, ., , 6'~3 According ~o the present invention there is pro-vided a cathode-ray tube comprising an envelope including a neck, a cone and a window portion, an electrode system provided in the neck to generate at least one electron beam, a layer which extends over the inner surface of the cone into the neck and of which at least the part extend-ing :Erom the neck-cone transition into the neck consists of an electric resistive material, and a getter which is arranged inside the cone and which is supported by means of an elongate resilient element, characterized in that the resilient element has a resilient clamping member which is clamped in the neck between the electrode system and the neck-cone transition.
:
The~invention is based on the recognition of the fact that the part of the resistive layer effective for ~; the end in~view is mainly restricted to the part extending in the neck of the tube. Therefore, a small distance between the clamping member and the electrode system, or ; between the clamping member and contact springs of the : :, 20~ electrode system contacting the~tube wall, will suffice.
The~clamping member may have any desired shape and in one embodiment consists of a metal band in the form ; of an open ring. In order to increase the friction between the band provided in its place and the tube wall, the~surface of the band contacting the tube wall may be roughened,~if desired.
The present invention will now be described by way of example with reference to the single figure of the accompanying drawing which ls a broken-away perspective :
~ 4-: ::
: ~ j",~:,, view of a neck and a part of the cone of a cathode-ray tube made in accordance with the invention.
The cathode-ray tube is a colour television dis-play tube having a glass neck 1 and cone 2. The inner wall of the tube is provided with a resistive layer 3 extending into the neck 1. The neck 1 comprises an elec~
trode system to generate three electron beams. For that purpose the electrode system comprises three electron guns each comprising a first electrode 4, a second electrode 5, a third electrode 6 and a fourth electrode 7. The elec-trodes 7 are secured to a centring sleeve 8 which is con-nected electrically by means of contact springs 9 to the part of the resistive layer 3 extending in the neck 1.
A getter 10 is secured, vla a resilient metal strip 11, to an open ring band 12 clamped in the neck 1~
The distance between the ring band 12 and the place where the contact springs 9 press against the resistive layer 3 is approximately 1.5 to 2 cm. The resistive layer 3 con-SlStS of approximateLy I part~hy weight of graphite powder, 6 to 10 parts by weight of iron oxide powder (Fe2O3) and : ~ .
1.5 to 3 parts by weight of an inorganic binder, for examplej potassium silicate or sodium silicate.
During operation of the tube the layer 3 and hence~also each of the electrodes 7 are at a potential of 25 ;approximately 25 kV. Ths electrodes 6 are at a potential of approxlmately 5 kV. In an;electric flash-over between an electrode 7 and an electrode 6, the dynamic resistance in the present example, that is the resistance defined as the quotient of the high voltage and the current strength : :
: :~ ::
~ -5-: '~
~ ~ 'q ~ ~:
~ ``.~, ~ :~ 6'~3 maximally occurring in the case of an electric flash-over, was approximately 200 Ohm.
The getter 10 can be assembled in the tube in a simple manner. For that purpose the ring band 12 has two eyelets 13 by means of which the ring band 12 can be slid on the jaws of a pair of tongs. For inserting the ring band 12 and the getter 10 connected thereto by the strip 11, the ends of the open ring band 12 are moved towards each other by tensioning the tongs and the assembly 10, 11, 12 can be inserted into the tube neck 1. As soon as the desired position of the ring band 12 has been reached, the tongs are relaxed so that the ring band 12 is clamped in the neck 1. The electrode system is then inserted into the tube neck 1 and the tube is then sealed and evacuated in the usual manner.
The ring band 12 may also be provided differ-ently with means~ with which it can be accommodated on an inserting apparatus. For example, instead of the eyelets 13, the ends of the open ring band 12 may be bent inwardly.
It is furthermore possible to use the ring band 12, or another suitable clamping member, to support a further : `: :
electrode, diaphragm or~lens element to influence the electron beam~s) generated by the electrode system.
The invention is further not restricted to tubes in which the electrodè system in the neck is connected to the reslsti~e layer by means of contact springs. The ; ~ invention may also be applied to tubes in which the elec-trode system is arranged in the neck of the tube so as to be fully insulated from the resistive layer, for example, ~::
.
tubes in which the part of the layer extending in the tube neck also constitutes an accelerating electrode.
':
:: ::
:: :
: -7-... : ~.
.
:
The~invention is based on the recognition of the fact that the part of the resistive layer effective for ~; the end in~view is mainly restricted to the part extending in the neck of the tube. Therefore, a small distance between the clamping member and the electrode system, or ; between the clamping member and contact springs of the : :, 20~ electrode system contacting the~tube wall, will suffice.
The~clamping member may have any desired shape and in one embodiment consists of a metal band in the form ; of an open ring. In order to increase the friction between the band provided in its place and the tube wall, the~surface of the band contacting the tube wall may be roughened,~if desired.
The present invention will now be described by way of example with reference to the single figure of the accompanying drawing which ls a broken-away perspective :
~ 4-: ::
: ~ j",~:,, view of a neck and a part of the cone of a cathode-ray tube made in accordance with the invention.
The cathode-ray tube is a colour television dis-play tube having a glass neck 1 and cone 2. The inner wall of the tube is provided with a resistive layer 3 extending into the neck 1. The neck 1 comprises an elec~
trode system to generate three electron beams. For that purpose the electrode system comprises three electron guns each comprising a first electrode 4, a second electrode 5, a third electrode 6 and a fourth electrode 7. The elec-trodes 7 are secured to a centring sleeve 8 which is con-nected electrically by means of contact springs 9 to the part of the resistive layer 3 extending in the neck 1.
A getter 10 is secured, vla a resilient metal strip 11, to an open ring band 12 clamped in the neck 1~
The distance between the ring band 12 and the place where the contact springs 9 press against the resistive layer 3 is approximately 1.5 to 2 cm. The resistive layer 3 con-SlStS of approximateLy I part~hy weight of graphite powder, 6 to 10 parts by weight of iron oxide powder (Fe2O3) and : ~ .
1.5 to 3 parts by weight of an inorganic binder, for examplej potassium silicate or sodium silicate.
During operation of the tube the layer 3 and hence~also each of the electrodes 7 are at a potential of 25 ;approximately 25 kV. Ths electrodes 6 are at a potential of approxlmately 5 kV. In an;electric flash-over between an electrode 7 and an electrode 6, the dynamic resistance in the present example, that is the resistance defined as the quotient of the high voltage and the current strength : :
: :~ ::
~ -5-: '~
~ ~ 'q ~ ~:
~ ``.~, ~ :~ 6'~3 maximally occurring in the case of an electric flash-over, was approximately 200 Ohm.
The getter 10 can be assembled in the tube in a simple manner. For that purpose the ring band 12 has two eyelets 13 by means of which the ring band 12 can be slid on the jaws of a pair of tongs. For inserting the ring band 12 and the getter 10 connected thereto by the strip 11, the ends of the open ring band 12 are moved towards each other by tensioning the tongs and the assembly 10, 11, 12 can be inserted into the tube neck 1. As soon as the desired position of the ring band 12 has been reached, the tongs are relaxed so that the ring band 12 is clamped in the neck 1. The electrode system is then inserted into the tube neck 1 and the tube is then sealed and evacuated in the usual manner.
The ring band 12 may also be provided differ-ently with means~ with which it can be accommodated on an inserting apparatus. For example, instead of the eyelets 13, the ends of the open ring band 12 may be bent inwardly.
It is furthermore possible to use the ring band 12, or another suitable clamping member, to support a further : `: :
electrode, diaphragm or~lens element to influence the electron beam~s) generated by the electrode system.
The invention is further not restricted to tubes in which the electrodè system in the neck is connected to the reslsti~e layer by means of contact springs. The ; ~ invention may also be applied to tubes in which the elec-trode system is arranged in the neck of the tube so as to be fully insulated from the resistive layer, for example, ~::
.
tubes in which the part of the layer extending in the tube neck also constitutes an accelerating electrode.
':
:: ::
:: :
: -7-... : ~.
.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A cathode-ray tube comprising an envelope includ-ing a neck, a cone and a window portion, an electrode sys-tem provided in the neck to generate at least one electron beam, a layer which extends over the inner surface of the cone into the neck and of which at least the part extend-ing from the neck-cone transition into the neck consists of an electric resistive material, and a getter which is arranged inside the cone and which is supported by means of an elongate resilient element, characterized in that the resilient element has a resilient clamping member which is clamped in the neck between the electrode system and the neck-cone transition.
2. A cathode-ray tube as claimed in Claim 1, charac-terized in that the clamping member is a metal band in the form of an open ring.
3. A cathode-ray tube as claimed in Claim 1 or 2, characterized in that the surface of the clamping member contacting the tube wall is roughened.
4. Getter support means for a television cathode-ray tube including a funnel and a neck, said getter sup-port means comprising an expansible member, the circumfer-ence of which while relaxed is greater than the circumfer-ence of the inner surface of the neck of the recipient tube, said expansible member being structured so as to be retained in the tube by the outward, self-retaining pres-sure of said member on said inner surface of said neck adjacent to the junction of said neck and said funnel, said expansible member providing fox the support of getter means by attachment of said getter means to said member.
5. Getter support means for a television cathode-ray tube including a funnel and a neck, said getter sup port means comprising an expansive split spring collar the circumference of which while relaxed is greater than the circumference of the inner surface of the neck of the recipient tube, said getter support means being structured so as to be retained in the tube by the outward, self-retaining pressure of said collar on said inner surface of said neck adjacent to the junction of said neck and said funnel, said getter support means providing for the sup-port of getter means by attachment of said getter means to said collar.
6. The getter support means as defined by Claim 5 wherein said collar has extending from an inner surface thereof a plurality of tab means for gripping and retract-ing said collar during installation of said getter support means in said cathode-ray tube.
7. An antenna getter assembly fox a television cathode-ray tube including a funnel and a neck, said getter assembly comprising, in combination, an expansive split spring collar, the circumference of which while relaxed is greater than the circumference of the inner surface of the neck of the recipient tube, a pan contain-ing a quantity of getter material, and resilient spring means for resiliently coupling said pan to said collar, said assembly being structured so as to be retained in the tube by the outward, self-retaining pressure of said col-lar on said inner surface of said neck adjacent to the junction of said neck and said funnel.
8. Getter support means for a television cathode-ray tube including a funnel and a neck, said getter sup-port means comprising an expansive split ring collar, the circumference of which while relaxed is greater than the circumference of the inner surface of the neck of the recipient tube, said getter support means being structured so as to be retained in the tube by the outward, self-retaining pressure of said collar on said inner surface of said neck adjacent to the junction of said neck and said funnel, said collar having extending from an inner surface thereof a plurality of tab means for gripping and retract-ing said collar during installation of said getter support means to said cathode-ray tube.
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Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7712214 | 1977-11-07 | ||
| NL7712214A NL7712214A (en) | 1977-11-07 | 1977-11-07 | CATHOD BEAM TUBE. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1164923A true CA1164923A (en) | 1984-04-03 |
Family
ID=19829486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000314372A Expired CA1164923A (en) | 1977-11-07 | 1978-10-26 | Cathode-ray tube |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5474669A (en) |
| BE (1) | BE871809A (en) |
| CA (1) | CA1164923A (en) |
| DE (1) | DE2847540C2 (en) |
| FR (1) | FR2408212A1 (en) |
| GB (1) | GB2007425B (en) |
| IT (1) | IT1100453B (en) |
| NL (1) | NL7712214A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2122414A (en) * | 1982-06-15 | 1984-01-11 | Thorn Emi Brimar Limited | Cathode ray tubes incorporating a protective resistor |
| JPS63264853A (en) * | 1988-02-22 | 1988-11-01 | Sony Corp | Getter support body structure for cathode-ray tube |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS432103Y1 (en) * | 1964-10-19 | 1968-01-29 | ||
| JPS432102Y1 (en) * | 1964-10-19 | 1968-01-29 | ||
| NL6900696A (en) * | 1969-01-16 | 1970-07-20 | ||
| JPS5128492B2 (en) * | 1972-04-25 | 1976-08-19 | ||
| US3939376A (en) * | 1974-12-26 | 1976-02-17 | Union Carbide Corporation | Alignment spring counteracting antenna type getter effect on electron gun alignment |
-
1977
- 1977-11-07 NL NL7712214A patent/NL7712214A/en not_active Application Discontinuation
-
1978
- 1978-10-26 CA CA000314372A patent/CA1164923A/en not_active Expired
- 1978-11-02 DE DE2847540A patent/DE2847540C2/en not_active Expired
- 1978-11-03 GB GB7843151A patent/GB2007425B/en not_active Expired
- 1978-11-03 IT IT29422/78A patent/IT1100453B/en active
- 1978-11-04 JP JP13623578A patent/JPS5474669A/en active Pending
- 1978-11-06 FR FR7831353A patent/FR2408212A1/en active Granted
- 1978-11-06 BE BE191568A patent/BE871809A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2847540C2 (en) | 1986-10-09 |
| NL7712214A (en) | 1979-05-09 |
| JPS5474669A (en) | 1979-06-14 |
| FR2408212B1 (en) | 1982-08-20 |
| DE2847540A1 (en) | 1979-05-10 |
| IT7829422A0 (en) | 1978-11-03 |
| IT1100453B (en) | 1985-09-28 |
| FR2408212A1 (en) | 1979-06-01 |
| GB2007425B (en) | 1982-01-27 |
| BE871809A (en) | 1979-05-07 |
| GB2007425A (en) | 1979-05-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |