CN1068970C - Cathode structure for cathode ray tube - Google Patents

Abstract

An improved cathode structure for a cathode ray tube includes a first metal tube which can receive an emission part and a heating element, a second metal tube constituting the cathode shielding, and means for retaining the first tube in position inside the second, wherein the retaining means are constituted by a single metal piece. In a preferential mode of implementation, the metal retention piece is constituted by a crown having branches extending in the direction of the axis of the crown.

Description

The cathode construction that is used for cathode ray tube

The present invention relates to be used to be inserted in the interior cathode construction of electron gun of cathode ray tube.

At present people more and more need cathode ray tube to be improved in screen intensity, working life, the performance lighted aspect time and the power consumption.These parameters all mainly depend on the structure and the type of negative electrode mostly, this negative electrode is used to produce electron beam and the screen of ray tube is scanned, general so far employed oxide coated cathode has arrived its limit and has just been replaced by dispenser cathode aspect these require, can reach bigger current density and have longer working life with it.

Dispenser cathode is operated in 1000 ℃-1200 ℃ the magnitude of temperature.Under this temperature, the expansion of material that should reduce to constitute this negative electrode is with the good stability of the electron gun that obtains this negative electrode and inserted.By adopting materials with high melting point and adopting the cathode branch support member of the appropriate size of restriction heat conduction loss to realize this reducing.

United States Patent (USP) 4,184,100 and 5,218,263 have described two kinds of structure types that are used to control expansion at present.These patents have adopted and have been cathode body cylindraceous basically, include radiating portion at the one end, and in cathode body, heating element is wrapping; Also have one to be heat shielding cover cylindraceous basically and to surround cathode body; And the device that is used in cylindrical cap, supporting this cathode body.

The device that is used for cathode support must have a stiff member, can reduce the heat leakage that is caused by heat conduction simultaneously.Bracing or strutting arrangement can be the support of being made by bonding jumper, and the cross section of bonding jumper is very thin to reduce heat leakage, and the end of this support is connected to a side of cathode body and the opposite side of cylindrical cap.In the Another Application form, support is perforated on the cylindrical portions may of cover, so that an end keeps fixing with cover, the other end is linked on the cathode body simultaneously.

When support is when bonding jumper is made one by one, will consider has a plurality of shortcomings.Because stent size is very little,, it needs extreme care so handling.The periphery sides that the end of bonding jumper is welded to cover can relate to and form a cocked bead (embossed border).The employing target body of bonding jumper can bring the very big uncertainty on the relevant location such as its height, concentricity and perpendicularity with respect to cover.And, adopt thin narrow bonding jumper also to increase manufacturing cost.

When support is when being pressed in directly on the barrel surface of cover, just need choose a kind of refractory material and constitute this cylindrical cap, and this practice can reducing the hot property of this cylindrical cap, influences the emission effciency of negative electrode thus.In addition, the cover of making of the refractory material can bring high manufacturing cost.

Cathode construction provided by the invention just can be eliminated the shortcoming of aforesaid structure.

A kind of modified model cathode construction that is used for cathode ray tube according to the present invention comprises that first metal tube, that can load a radiating portion and a heating element constitutes second metal tube of cathode shield, and make the pipe of winning be in clamping device in second pipe, wherein clamping device is made up of single metalwork.In an applied preferred form, the metal retention means is made of a crown part, and this crown part has a plurality of along its axially extended branch.

In the drawings:

Fig. 1 and Fig. 2 are respectively the top view and the section side elevation of the cathode construction of prior art;

Fig. 3 and Fig. 4 are respectively the another kind of similarly top view and the section side elevation of cathode construction in the prior art.

Fig. 5 and Fig. 6 have shown a part of application apparatus that is used for a cathode tube is clamped in another pipe according to of the present invention;

Fig. 7 and Fig. 8 show respectively according to the section side elevation of cathode construction of the present invention and top view;

Fig. 9,10 and 11 represents the decomposition diagram according to second embodiment of cathode construction of the present invention, top view and section side elevation respectively;

Figure 12 and 13 expressions are according to the perspective view of two vestlets that adopted in the cathode construction of the present invention.

As illustrated in fig. 1 and 2, a kind of dispenser cathode structure of prior art comprises a cylindrical shape first metal tube 2, for example is the nickel chromium triangle pipe, is radiating portion 1 at the one end.One heating element 5 is placed in the pipe 2.One cylindrical shape, second metal tube 4 is holding this first metal tube 2; And as a heat cover preventing to fall by the thermal loss that heating element 5 is produced, and the thermal output that increases cathode construction.First metal tube 2 is by support 3 fix in position in second metal tube 4, and support 3 is stamped to form by the refractory material and the one end is soldered to the limit 7 of second metal tube 4, and its other end is soldered to the surface of first metal tube 2.Welding on limit 7 is very difficult, and manages the 2 location need extreme cares with respect to pipe 4, and this is because the size of support 3 is too little.When cathode construction is located in electron gun, generally all be that pipe 4 is used as object of reference, if the location of first pipe 2 in second pipe 4 is inaccurate, then electron gun and metal tube can correctly not worked.

In second kind of prior art shown in Fig. 3 and 4, each support 6 of clamping first pipe 2 is that the cylinder by second pipe 4 directly is stamped to form, and the one end still is the part of this second pipe.Support 6 extends in second pipe 4, and its freely an end be soldered to first and manage 2.In this prior art embodiments, the material of the second selected pipe still is limited to the refractory material, so just makes heat shielding efficient reduce and hinder the thermal output of negative electrode.In addition, owing to be covered with a minimum thickness (approximately 25-30 micron), also need the difficulty that contacts solder joint and have these materials of punching press, so the thickness of support and width all are restricted.

In a kind of application of the present invention formed, first pipe 2 was fixed in second pipe 4, and as shown in Figure 11, this is to finish by single 16, as illustrated in Figures 5 and 6.This single 16 is that it is extremely thin, preferably 15 to 25 microns by the hollow cylindrical body formation of refractory material (for example tantalum).Heat-proof quality between cathode body and the cover is significantly improved, so the time that makes negative electrode rise to working temperature has also shortened.

Comprise for single 16 a crown body 10 of cylindrical shape, wherein have a plurality of from these crown body 10 upwardly extending branches 11.These branches are stamped to form on the barrel surface of the refractory material of making these parts.These branches along crown body 10 around clocklike to be spaced.For guaranteeing rigidity location fully, need to adopt at least three branches, form 120 ° therebetween.Shown in Fig. 7 and 8, these branches extend in second pipe 4, so that make their end 12 can be connected to first pipe 2, for example by welding.The last assembling of cathode construction is to finish by first pipe 2 is inserted second pipe 4.The external diameter of crown body 10 is slightly littler than the internal diameter of second pipe, 4 ends.After first pipe 2 was with respect to second pipe, 4 location, crown body 10 managed 4 with regard to soldered (for example passing through laser welding) to second.

Like this, just can use and come work, simultaneously than the independently support in the original technology stronger mechanical rigid be arranged again than material thinner in the prior art.The assembling of this negative electrode becomes simpler, and its repeatability is improved.

Fig. 9,10,11 and 13 has shown another embodiment, and wherein, the internal diameter of crown body 10 is bigger slightly than the external diameter of second pipe, 4 ends.Second pipe 4 has slot 15 on the circumference at an upper portion thereof, thereby when the last assembling of cathode construction first pipe 2 is inserted in second process of managing in 4, so that allow branch 11 by extending in second pipe 4.This combining structure has its advantage, promptly it to make the pipe 2 of winning be automatically to finish with respect to second pipe, 4 relative positionings, single 16 bottom that is fixed on slot 15 simultaneously.Obtain cathode assembly at last, wherein again do not need to regulate the relative position of first pipe with respect to second pipe by meticulous measuring process.This improvement has produced fabulous repeatability on the relative positioning of cathode construction parts.

In addition, the application of this structure is not only limited to the dispenser cathode structure, can be used for the oxide coated cathode structure yet and obtains same advantage.

Claims (6)

1. a cathode construction that is used for cathode ray tube comprises one first metal tube (2), is used to load an emission element (1) and a heating element (5); One second metal tube (4) is round described first metal tube; And, be used for the device that clamping is positioned described first pipe of described second pipe, it is characterized in that,

Described clamping device is made of single metalwork (16), and described single metalwork (16) comprises a crown body (10), and this crown body has a plurality of with its axially extended branch (11).

2. cathode construction as claimed in claim 1 is characterized in that, has three described branches (11) at least.

3. cathode construction as claimed in claim 1 is characterized in that, described crown body (10) is fixed on described second metal tube (4).

4. cathode construction as claimed in claim 3 is characterized in that, described crown body (10) is placed on described second metal tube (4) the inside.

5. cathode construction as claimed in claim 3 is characterized in that, described crown body (10) is placed in the outer surface of described second metal tube (4).

6. cathode construction as claimed in claim 5 is characterized in that, described second metal tube (4) has the slot of going out (15), and described branch (11) extends to described pipe inside by this groove.

Images