CN1040813C - In-line type electron gun assembly for use in colour picture tubes - Google Patents

Abstract

An electronic gun component shaped like Chinese character 'yi' comprises a first grid, a second grid, a third grid and a fourth grid. The fourth grid is made into a basin or cup shape. A main magnetic focusing lens is composed of an axial alignment hole in the third grid and the fourth grid. An auxiliary electrode is arranged between the fourth grid and a picture tube shield cup and includes three common tubular backward auxiliary holes connected with a flat plate, and each auxiliary hole includes two opposite recesses. Each recess preferably has a common rectangular shape, is in accordance with a beam alignment direction, and is connected with a bossed lip erecting forwards and surrounding the inner edge of the fourth grid hole.

Description

The I-shaped electron gun assembly that is used for chromoscope

The present invention relates generally to the electron gun of color cathode ray tube (CRTS), relate in particular to and a kind ofly constitute the improvement electrode assemblie of electron gun structure by magnetic lens, it can not cause the astigmatism of main magnetic focusing lens or form the image distortion of elongated luminous point on the cathode-ray screen.

The conventional cathode ray tube that is used for color TV set generally includes an I-shaped electron gun assembly.This I-shaped electron gun assembly can be made unipotential type or biopotential type.Biopotential type is used always.Electron gun has three negative electrodes usually, so that launch three electron beams.Cathode ray tube constitutes image by forming many luminous points on focusing and the screen of scanning beam in ray tube.After the many alignment apertures that form on the electron beam process focusing electrode, be focused and be converged to luminous point.Aggregation bunch can show as a luminous point on screen, this luminous point can be ellipse garden shape, common round spot or a kind of elongated band or bar.

Fig. 1 illustrates the structure of color cathode ray tube 1, and it has traditional I-shaped electron gun assembly 10, as mentioned above.Phosphor dot pattern 2 (being to comprise the pattern that interweaves and form by red green and blue point or luminous point, such as is known in the art) be at glass bulb panel 4 inner surface 4 ' on deposit form.Shadow mask 6 is installed in the cathode ray tube, and leaving panel 4 has a gap.Glass funnel 8 is connected with panel 4, is used for protecting and the encapsulation shadow mask, and cathode ray tube is vacuumized.Electron gun structure 10 is installed in the neck 12, and neck is connected with the tail end 9 of funnel 8.Outside electrical connection 11 is that welding is on the tail end 12 of neck.

Above-mentioned is conventional structure.In addition, the general work principle of cathode ray tube is known in affiliated field, only describes the background technology that the present invention will solve problem below.

As prior art is disclosed, when electron gun structure adds high voltage, from three negative electrodes of electron gun, launch electron beam 14.Heat the thermionic emitter of deposit on each negative electrode by cathode heater, produce thermionic emission.

The hot electron of emission is because during by first grid (so-called control the utmost point), owing to attraction becomes a narrow beam 14.Forming a preposition magnetic lens between first grid and bucking electrode (so-called second grid) focuses on electron beam.Main magnetic focusing lens is made of third and fourth grid.Each bundle of three electron beams all is to be attracted by four all electrodes, and magneticaction causes electron beam to focus on and be converged to very narrow bundle in electron beam.Electron beam is realized by the magnetic deflection coil 16 of electric control on funnel 8 in the scanning on the cathode-ray tube shiels.

Beam cross section shape after being focused is known bundle point-like type.As mentioned above, focused beam can form a hot spot on screen, can be ellipse garden shape, common round spot or elongated band or bar.The pattern remarkable influence of luminous point the image dissection resolving power and form the definition of image on screen.The luminous point pattern is by the decision of the physical structure of magnetic focusing lens, is especially determined by the main focusing lens between third and fourth grid.

The garden luminous point is for the bar shaped phosphor dot, cause the image of low resolution easily, the cathode-ray screen that adopts the garden shape luminous point of many close packings to be constituted has nonconforming interval between two adjacent spot, during work, these are not contacted by electron beam at interval, so keep dark.The result forms has the very poor blurred picture of definition.

Desirable light spot form should be a rectangle, promptly owing to the close packing of luminous point pattern, can make not have the dark space between the luminous point.Regrettably because the physical characteristic of electron beam wants to realize that complete rectangle is impossible.

Therefore, ellipse garden luminous point pattern is the most desirable.It can make the dark space on the screen reach minimum, and near genuine rectangle luminous point.When employing had rectangle luminous point screen, ellipse garden shape electron beam can provide good image quality equally.When the fluorescence pattern that adopts ellipse garden luminous point or stripe shape on cathode-ray tube shiels, and when using ellipse garden shape electron beam, it almost is to mate exactly that electron beam provides shadow mask hole and screen luminous point.So the ellipse garden pencil of forms is more desirable,, obtain the improvement of brightness and the reduction of moir thus because electron beam can be equal to all parts of the topped bar shaped pattern in ground.On the contrary, garden shape electron beam only contacts the part of ellipse garden shape luminous point or band, therefore causes the reduction of brightness and image quality.

Many in the past researchers once attempted to make a big condenser lens so that produce ellipse garden bundle unsuccessfully.For example United States Patent (USP) 3987328 (Yoshida etc.) has disclosed a kind of main focusing lens, has the hole at third and fourth grid.These holes have long tubular sleeve, like this condenser lens thereby become big.This opposed area method by deep draw third and fourth grid is a known method for a kind of big main focusing lens is provided.

But, can reduce the size of Shu Guangdian significantly according to the big condenser lens of manufacturings such as Yoshida.The flexibility difference of the center and peripheral of cathode-ray tube shiels also produces spot distrotion simultaneously.

Spot distrotion can be proofreaied and correct by the dynamic convergence device, and second grid has a pair of auxiliary electrode that has vertical slot at least like this, to this slot making alive.For example United States Patent (USP) 4443736 (Chen) proposes a kind of electron gun that has this dynamic convergence device.

But this kind dynamic convergence method is unfavorable, because a kind of adjunct circuit of controlling this device also must be provided.

Can make the electron beam section shape of launching from electron gun be ellipse garden shape by means of the elongated hole on the second grid.In I-shaped electron gun, second grid can be made a kind of flat board that level is cracked that has, and can change the ellipse garden Shu Guangdian that is wanted to obtain easily.Regrettably adopt the additional plate electrode that has horizontal slot, need be welded on the second grid, so just increased manufacturing expense and complexity.Therefore, be desirable to provide and have and the flat board electrode said function effect of cracking, collaborative ellipse garden bundle condenser lens, and need not add the device of other parts.

So characteristics of the present invention are a kind of improved electron guns, it can produce ellipse garden Shu Guangdian, and is complementary with phosphor screen bar shaped pattern.Another characteristics are to guarantee accurate ellipse garden bundle condenser lens, have dynamic convergence correction, are a kind of single simple and easy devices of making.The present invention is used for a kind of I-shaped electron gun, and it has the first, second, third and the 4th grid, and the 4th grid is made basin shape or cup-shaped.Main magnetic focusing lens is formed by some holes of axial adjusting to a line on third and fourth grid.An auxiliary electrode is set between the shielding cup of the 4th grid and cathode ray tube, and this auxiliary electrode has 3 common tubuloses that connect with flat board, and the back is to the via hole of (rearwardly-facing).Each via hole comprises the recess of two opposite side.Each recess preferably has identical ordinary rectangular, and vertical with the beam alignment direction.Each recess should be coupled along the upright protruding lip forward of the 4th grid hole inward flange.The axial length of each via hole should be complementary with the degree of depth of cup-shaped the 4th grid.The external diameter of lip is the internal diameter of via hole no better than, so just auxiliary electrode can be connected on the 4th grid closely.

Other advantage of the present invention and characteristics will explain middle embodiment below in conjunction with the accompanying drawings.

Fig. 1 is the side cutaway view with common color picture tube of I-shaped electron gun.

Fig. 2 is the side cutaway view of electron gun electrodes assembly of the present invention.

Fig. 3 is the exploded perspective illustration of the 4th grid shown in Fig. 2 assembly.

The preferred embodiments of the present invention following detailed description.In order clearly to see, adopted buzzword.In any case the particular term of Xuan Zeing has comprised all technical equivalents things like this, promptly referring to be implemented in has similar function in essence, similar means is substantially arranged and reach similar in fact result.

Electron gun electrodes assembly of the present invention is seen shown in Figure 2.This assembly can be installed in the tail neck portion in the chromoscope, i.e. 10 of Fig. 1 electron gun position.For the sake of clarity, the afterbody of this device is represented with R in Fig. 2, and front end indicates with F; Cathode-ray tube shiels is installed in front or the place ahead, and the afterbody of this assembly is installed in the television receiver shell usually.

As shown in Figure 2, the emitter of electron gun structure 10 can comprise a cathode assembly 22, and it comprises a plurality of cathode sleeves 18 and a plurality of thermionic electron emitter 20 that is deposited on the sleeve again.As everyone knows, in typical trichromoscope, have three independent cathode sleeves and emitter so that produce three electron beams that separate and project three kinds of colors, promptly red, blue and green screen luminous point.In this explanation, the part in addition of corresponding red bundle marks with letter r, and the part in addition of corresponding blue bundle marks with B, and the part in addition of corresponding green beam marks with alphabetical G.

In known technology, supplementary lens can separate with being installed in second grid 26 equally, but constitutes near its 3rd grid 28.

Usually, main focusing lens constitutes with third and fourth grid.The 3rd grid 28 can be used the electrode 28a of a pair of cup-shaped of coupling or peviform, and 28b constitutes.Electrode pair 28a, 28b take the opposing open end coupling.The 3rd grid also comprises the hole 28R of a plurality of elongations, 28G, and 28B, they are made of the sleeve or the pipe of a plurality of elongations.28R, 28G, each Kong Douyu the first of 28B, second grid is in line with emitter and aims at.

The 4th grid 30 is relatively to install, and and the elongated hole 28R of the 3rd grid 28,28G, 28B is aligned to straight line.Best the 4th grid is also done cup-shaped or basin shape.As shown in Figure 3, above-mentioned grid all is fixed on the relevant position of glass bar 38.

The assembly of Fig. 2 also comprises an auxiliary electrode 32, and it is by one flat plate 32b and back to the common elongated hole 32R that extends, 32G, 32B composition.Hole 32R, 32G and 32B can constitute with sleeve or pipe 33.Auxiliary electrode 32 is installed in the 4th grid, between cathode ray tube shielding cup the 34 and the 4th grid.The inside of the elongated hole of auxiliary electrode being inserted in the 4th grid 30 just can make auxiliary electrode be installed on the 4th grid 30.Fig. 3 is the decomposition diagram of this assembly.A hole of the 4th grid is all aimed in the hole of each extension electrode.

In order to realize that ellipse garden shape is assembled or the shaping of electron beam by auxiliary electrode, this elongated hole 32R, 32G, each among the 32B all has the recess 32a (as shown in Figure 3) of identical aligning direction.The preferably all rectangular otch of each recess on the perisporium 32c of the garden of pipe 33.

As shown in Figure 3, auxiliary electrode being inserted the 4th grid can make auxiliary electrode 32 be installed on the 4th grid.In this arrangement, dull and stereotyped 32b extends whole the 4th grid and forms a ring flange at the 4th grid 30 and 34 of shielding cups.The assembly of its suit is preferably seen shown in Figure 2.

For elongated hole 32R with auxiliary electrode 32,32G, the hole 30R of 32B and the 4th grid 30,30G, 30B is connected, hole 30R, 30G, 30B form in the inboard of the 4th grid the back to upright projection or so-called lip 34R, 34G, 34B.Best each lip 34R, 34G, the external diameter of 34B is elongated hole 32R no better than, 32G, the internal diameter of 32B.This arrangement architecture can make each elongated hole back to flange be close to each lip 34R, 34G, 34B, and auxiliary electrode connected or be fixed on the 4th grid.

Make auxiliary electrode available metal material, adopt known deep draw technology, on dull and stereotyped 32b, stamp out three slotted hole 32R, 32G, 32B.These three punching hole 32R, 32G, 32B has recess, and this recess adopts common Metal Cutting technology to carry out cutting form symmetrically along the direction of identical unanimity.

During work, launch hot electron from negative electrode 22, when through form between the second and the 3rd grid 24,26 give condenser lens the time just form electron beam.Give the anterior 28a of focused beam then by the 3rd grid 28.When electron beam focuses on and assembles through between the rear electrode 28b of the 3rd grid 28 and the main focusing lens between the 4th grid 30 time.At this moment, the anode high voltage quickens towards cathode-ray tube shiels electron beam.On auxiliary electrode 32, add anode voltage, the high voltage of 25KV to 30KV for example, meanwhile, the 4th grid 30 is too.Auxiliary electrode 32 is installed in the inside of the 4th grid 30, elongated hole 32R, and 32G, the slotted hole 28R of 32B and the 3rd grid 28,28G, 28B constitute a big main focusing lens together.Consequently produce the further focusing of electron beam, electron-beam convergence is become ellipse garden shape section.

At this duration of work, the recess 32a on the auxiliary electrode 32 is because the attraction of electron beam during through recess 32a, can make the last of electron beam and down two parts break away from the influence of elongated hole.In contrast to this, electron beam is focused on or is surrounded by the C type wall 32C of each elongated hole.Consequently electron beam presents ellipse garden shape cross section.Though the suction effect of recess causes that the whole process that electromagnetic force acts on electron beam is a known technology, in any case the structural arrangements of the recess of Pi Luing is the instruction of never crossing in existing technology and indicates here.

As mentioned above, the invention provides the device that makes electron beam be the shape convergence of ellipse garden, produce electron beam with ellipse garden shape cross section.What adopted is the plain mode of machinery and electronics.According to the size of the ellipse garden shape electron beam that device of the present invention the produced band of shadow mask or the area of bar hole no better than.Therefore, avoided the blind of bar shaped fluorescence pattern by the ellipse garden shape electron beam that this device produced.Correspondingly, the brightness of cathode-ray tube shiels and the decline of acquisition distortion and Moire fringe have been improved.In addition, because the present invention only need install an auxiliary electrode on the 4th grid, so complicated extra part, circuit or unnecessary manufacturing process all can be avoided.

The present invention imagines many mutation, except that the concrete disclosure of the present invention, and can also be with multiple embodied in other.So protection scope of the present invention should determine according to claims.

Claims (8)

1. an I-shaped electron gun assembly (10), comprise the first, second, third and the 4th grid (24,26,28 and 30), it is characterized in that: described the 4th grid (30) comprises a hole (30R with three alignings, 30G and 30B) substrate and a auxiliary electrode (32) with three sleeves (33) of aiming at described hole (30R, 30G and 30B), each described sleeve (33) comprises at least two recesses (32a) that are formed on described sleeve (33) longitudinal edge.

2. I-shaped electron gun assembly as claimed in claim 1, wherein said recess is aimed at described hole.

3. I-shaped electron gun assembly as claimed in claim 1, described hole on the wherein said substrate comprise lip around the edge in described hole (34R, 34G, 34B), described lip is vertically aimed at the described sleeve on the described auxiliary electrode, and the outer rim of described lip is close to the inner edge of described sleeve.

4. I-shaped electron gun assembly as claimed in claim 3, the length of wherein said sleeve equals the length of described the 4th grid.

5. I-shaped electron gun assembly as claimed in claim 2, the height of wherein said recess is less than half of described length sleeve.

6. yi word pattern electric gun assembly as claimed in claim 2, wherein said recess is a rectangle.

7. I-shaped electron gun assembly as claimed in claim 5, wherein said recess is a rectangle.

8. I-shaped electron gun assembly as claimed in claim 7, most cun described whole neighboring that has defined described the 4th electrode, the whole neighboring of wherein said substrate is very little to the greatest extent.

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