DE1222170B - Cathode ray tubes with means arranged between the deflection system and the luminescent screen for enlarging the deflection angle of the electron beam - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

HOIj

German class: 21g-13/23

Number: 1222170

File number: A 34447 VIII c / 21 g

Filing date: April 16, 1960

Opening day: August 4, 1966

■ The invention relates to a cathode ray tube with an electron gun, a deflection system, a fluorescent screen and with between the deflection system and the Luminous screen arranged means for increasing the deflection angle of the electron beam.

It is desirable to have a maximum of beam deflection each time the cathode ray tube is used in the tube and to achieve a maximum of the luminous screen brightness. Even though it is possible to achieve this goal in part by measures such as increasing the normal deflection voltage or current in the tube, the known measures are limited in that they are generally inadequate Make demands on the auxiliary circuits of the tube. Therefore z. B. the required voltage range and the electrical power that would be required for this is unusual, so that a common use these measures appear to be excluded. It also includes the additional acceleration of the Radiation in the cathode ray tube poses a problem. A radiation acceleration to generate a high radiation energy before the beam deflection is considered inexpedient because Difficulties arise in the distraction system, d. H. Problems, the desired distraction and control of the beam. Accelerating the beam after deflection while avoiding the On the other hand, the problem mentioned above brings again problems related to image distortion with himself. Although systems are known to effect the acceleration after the deflection, so Under such circumstances the resolving power of the tube suffers, so that the systems of such Types have an inherent limitation, at least in their presently known Shape. Furthermore, the conventional methods of post-acceleration are aimed at determining the direction of deflection of the rays, and are therefore only applicable where the magnification of the Radiant energy is going on without improving tube sensitivity.

In a known deflection arrangement for cathode ray tubes, the required deflection angle of the beam is to be achieved by lower amplitudes of the deflection voltage or deflection current than in the previous arrangements, in that in the beam direction behind the deflection means a magnetic cylinder lens enlarging the deflection angle and in the beam direction in front of the deflection means an opposite one acting cylinder lens attached cathode ray tube with between the
Deflection system and the fluorescent screen
arranged means to enlarge the
Deflection angle of the electron beam

Applicant:
Abtronics, Inc.,
Livermoore, Calif. (V. St. A.)

Representative:

Dipl.-Ing. F. B. Fischer, patent attorney,

Rodenkirchen-Weiss

Named as inventor:
Harvey M. Owren,
Livermoore, Calif. (V. St. A.)

Claimed priority:

V. St. v. America April 16, 1959 (806 886)

is arranged, which compensates for the distortion of the beam cross section caused by the former cylinder lens. In the event that only the magnetic cylinder lens arranged in the beam direction behind the deflection means were present, the beam would have an elliptical cross-section, so that an undesirable Distortion of the beam cross-section would be the result. By arranging the in the direction of the beam in front of the deflection means lying cylinder lens, the beam is now predistorted in such a way that the first-mentioned distortion will be annulled. - The known embodiment is therefore limited to that particular oriented magnetic fields generated outside the tube are provided, which increase the magnification of the deflection angle and, in connection therewith, a compensation for those caused by the deflection means Cause distortion.

In contrast, the invention aims to solve the problem of increasing the deflection angle, which at the same time also with simple means and without the difficulties mentioned above Allowed to achieve an increase in the kinetic energy of the electron beam.

This is the case with a cathode ray tube, which uses an electron source to produce a directional Electron beam, a fluorescent screen to collect

609 608/301

I 222 170

gen and imaging of the electron beam, deflecting the pipe center line between the electrodes and the means for the controllable deflection of the electron screen and have their center point and their Konstrahls by deflection signals and between the sides of the cavity to the screen. It is preferred steering means and means arranged on the screen for at least one of the electrodes in an almost spherical shape, Enlargement of the deflection angle of the electron 5 and according to a further preferred embodiment beam has, according to the invention thereby achieved, form can form the electrode facing the screen that the means for increasing the deflection angle have a funnel-shaped opening towards the screen of the electron beam from a plurality of extensions in the direction of the beam.

arranged one behind the other and increasing with- According to a further advantageous embodiment The distance from the deflection system of higher po- io three electrodes are provided, their common potential lying spherical segment or hemispherical center of curvature between the electrodes and shaped electrodes, which have a common deflecting means on the pipe center line, where seeds are located Center of curvature on the pipe center - at each electrode for the passage of the electron line to have. The generated fields cause a beam of a central, electron-permeable part enlargement of the deflection angle and an acceleration 15, and which generate electric fields, their generation of the electron beam. Lines of force emanate from the center of curvature,

In contrast to known systems, the loading such that the electron beam is deflected radially and

bring about acceleration after the distraction, is amplified.

with the described device the elec- Fig. 1 shows a schematic representation of a

electron beams an additional acceleration granted ao cathode ray tube with the described device

and their original distraction increased, tang;

without causing image distortion. This becomes Fig. 2 shows a schematic representation of a

by the introduction of spherical electrical part of a cathode ray tube including one

Reached fields in which the radiation acceleration other embodiments of the described input

is effected in the direction of deflection and 25 direction;

not parallel to the tube axis. In this way, F i g. 3 shows a schematic representation of a

not only the rays in the cathode ray part of a cathode ray tube including one

tube further accelerated, but also in a further embodiment of the device and

uniformly further deflected so that the F i g. 4 shows a schematic representation of a

resulting beam on the cathode 30 part of a cathode ray tube including still

Radiation tube screen in an additional radial one embodiment of the described device

Deflection impinge, so that the track on the device to increase the deflection angle.

Umbrella expanded and enlarged and at the same time The F i g. 1 shows in schematic form the cathode

the beam becomes more energetic, as a result of which the beam tube 11 with the evacuated piston 12.

enlarged track on the screen becomes lighter. This 35 I _n accordance with the usual contractions

is, without in any way the track resolution of cathode ray tubes, the bulb 12 has a

able to affect or in any cone 13 mit.einem luminescent screen 14 and one

To distort the image or representation, have neck 16. The electron beam source 17 is in

achieved. Arranged neck. This electron beam source 17

It is therefore a cathode ray tube with 40 generated an electron beam that runs along the axis better sensitivity created, at which a 20 of the cathode ray tube, which the tube maximum the enlargement of the tube is achieved. screen 14 interspersed at its center, runs.

Another advantage is that a cathode and an electron lens 18 is provided. To obtain a beam tube improvement, which includes a front beam direction behind the lens system 18, a beam acceleration 45 steering devices 19 spaced from each other according to the beam deflection without image distortion are provided along the tube axis, which allows two deflections, and an improved cathode is obtained - Pairs of plates for the horizontal and vertical radiation tube, which includes devices that consist of directing the electron beam. Of course, electron beams in it in a deflected direction, electromagnetic deflection devices can also be used to increase the beam energy. An electron beam accelerates, while at the same time the beam deflection 21, which is emitted by the radiation source 17, is enlarged. ^J and axially through the primary electron lens 18

According to a preferred embodiment, when passing through the deflection die the convex sides of the electrodes are radially deflected towards the shielding device 19, these facing away, and the electrodes are symmetrical to the 55 steering normally takes place in such a way that the The raw center line is spaced apart, with its bundle of rays imparting the desired property common center of curvature in the distance, such as by using a of the distraction means. The electrostatic deflection systems with suitable modu electrodes are useful in the area in which the elected person has deflection potentials.

electron beam impinges on them, as grids or sieves 60 For the sake of simplicity in FIG. 1 by the punkderart formed that they the electron beam based line 22 shown shows the single beam let through. The path which a beam occupies can also be the path which is closest to the deflecting means Electrode on which the screen pulls through the deflection device 19 in a conventional manner turned convex side an emissive surface cathode ray tube exhibiting a certain radial deflection, which experiences a larger number of electrons 65 kung. As already mentioned, the emitted than hit the concave side. known cathode ray tubes with regard to the maximum

Another advantageous embodiment consists of paint radiation energy restrictions,

in the fact that the electrodes have a common, because it means that the acceleration of the rays

5 6

usually located in the electron lens or electron electrodes 26 and 31, although they too

source is carried out and therefore this acceleration can be arranged at a different location. the

before the deflection of the beams, i.e. in the case of an electrode 31, it is also possible to

very high radiation energy or velocity.

which results from excessive acceleration of the 5 The acceleration and deflection of the electrical

Blasting results, takes place, the deflecting device nenstrahl is through the above-described elec-

no longer causes the desired beam deflection by the application of

can call out. This results from the limited suitable potentials on these electrodes, so as to

Time during which the electron beam exerts the deflecting and accelerating electric fields

to create directing forces of the deflecting device in the beam path. The electric potential

fen is, and it can be seen that these deflection tiale are placed between the electrodes in such a way-

is a direct function of the jet velocity. places that the first electrode 26 with respect to the elec-

In the case of the known cathode 31, the sensitivity is a relatively negative potential and

The beam tubes are limited by being strong and maintaining the intermediate electrode 36 on

Beam deflections a large distance between 15 a medium potential is kept, its value

The baffles need to be deflected by the spatial arrangement of this electrode

Beam does not graze this. As the distance between the other two electrodes 26 and 31 increases

but there is a dependency between the baffles. The electrodes 26, 36 and 31, respectively, are over

lesser influence on the beam by a specific conductor 41, 42 and 43 with suitable taps

tes potential applied to the plates. When using 20 voltage divider resistor 44 connected between

Using the described device, the reticles can be located at the poles of a voltage source as they are

Steering plates are arranged close to one another, for example as shown as a battery 46.

that only very low deflection potentials are required The intermediate electrode 36 is on a potential

will. tial, with which the spherical deflection and

As in Fig. 1 is behind the deflection front 25 acceleration field is maintained. How do-

Direction initially a first electrode 26 is provided, the electrode 36 is at a potential

which is symmetrical with respect to the beam axis from about 0.7 of the total voltage between the

is ordered, held close to the deflector electrodes 26 and 31, such as

device 19. This first electrode 26 has a half- through connection with the center of a logarithmic

spherical part 27, which is to be turned to the screen 14 30 mix resistance 44. In order to achieve the desired spherical

det and has a radiolucent portion. Anyone can maintain a professional field training

This permeable part of the electrode 26 is the immediate desired number of electrodes with suitable ones

bar arranged on the tube axis. The spherical potentials are applied, although something too

Electrode part 27 is arranged so that different potentials can be applied

Center of curvature 29 of the spherical upper 35 to distort the field and certain desired

surface is on the pipe axis. In the distance of producing results, such as the compensation for

the first electrode 26 is located on the pipe - any other cause of distortion or some other

axis another electrode 31. This further elec- tric direction of the beam on a plane

trode 31 also has a spherical surface, screen.

for example a hemispherical end part 32, the 40 with the correspondingly suitable potentials Has a radius of curvature, the substantially lying electrodes 26,31,36 between the is larger than that of the spherical part 27 of the Elek deflectors 19 and the screen 14 of the trode 26, which creates an electric field with the same curvature cathode ray tube, telpunkt 29 owns. The electrode 31, which in front of it has field lines practically spherical around the pipe radially from the pipe axis so far away 45 axis. Between electrodes 26 and 31 is arranged that it is on the wall of the housing thus an electric field which equipot-12 is applied, is likewise with a central ray- tiallinien, which on spheres with the electrodransparent Part equipped as in F i g. 1 dardenzentrum 29 are the center and their position is set, which has a large opening 33 which increases potentially outwardly therefrom. The Zwipraktisch can be as large as the fluorescent screen 14. 50's electrode 26 only acts to further this field Because the electron beam is fixed when passing through this, especially when the spatial AbElektroden is radially deflected, the radiation level of the electrodes 26 and 31 must be large. When opening be so large in the electrode 31 that the aim of the electric field, which is caused by the Beam 21 does not strike the electrode. Is caused between the electrodes described is grounded Electrodes 26 and 31 can be a further elec- tric 55 that thereby create a potential gradient both Trode 36 may be provided, which has a spherical top in the axial direction of the tube and in the radial direction surface 37 has, is provided with the same center point 29 direction.

like the spherical surfaces of the other elec- When the electrode 31, which the phosphor screen 14 trode, and which has a radius of curvature that is closest to positive potential with respect to between the radius of curvature of electrode 36 60 of electrode 26, which is close to the deflection and the electrode 31 lies. Similar to the above devices 19 is held, this is used described electrodes 26 and 31 is the intermediate potential gradient to the electrons within the electrode 37 with a central radiation permeable field in the axial direction of the tube and in the radial direction gene part 38 is provided, which is symmetrical about the direction to move towards the screen 14. A Tube axis is arranged and an unobstructed 65 electron beam, which passes through the deflector for the beam 21 was deflected by the electrode device 19 and by the electrode 26 equips. In the embodiment shown, the passes through, thus enters a spherical electrical intermediate electrode 26 in the middle between the cal field of considerable size, in which there is a po-

7 8

tentialgradient of suitable polarity is in order to also force this outwardly from the tube axis radial electrons both radially outwardly, as deflect. The beam through the field, which also moves towards the screen 14. By means of these electrodes being maintained, with the field, which is caused by the described acceleration and not running parallel to the tubular electrode, becomes a deflected 5-axis and therefore does not have a distorting effect on the electron beam being accelerated against the screen 14 so that the intensification is not accompanied by a low and at the same time radially reduced resolving power from the tube axis.
distracted from. Since the electron acceleration takes place in the direction of deflection described, there is no device shown in FIG. 3 of the drawing. Distortion of the beam image, as in the case of elec- In this embodiment, a first semitricular fields would be the case, which perpendicularly spherical electrode 61 is provided, which runs right to the tube axis. In addition to the center of curvature 62, which is arranged on the beam axis 20 in the general case of precisely spherical fields, but now such variations of the FeI-oriented that the convex electrode surface of the can be used as they are necessary around 15 the deflection device 19 faces. To compensate for these distortions, which otherwise lead to an electrode 61 behind the deflection device 19 which leads to the distortion of the image for other reasons, and which can be zenren with a cathode ray tube. This is achieved by changing the shape of the central opening or one for electron beams of the intermediate electrodes or by changing the permeable part 63 about the pipe axis 20 from potentials applied to it. 20 provided in diameter. Furthermore, a modification of the device described is an additional electrode 64 in the form of a hollow sphere is partially shown in FIG. 2 illustrates, in which the essentially shaped element with the same center 62 as borrowed in FIG. 1 electrodes 26, 31 and the electrode 61 are shown, but with a significantly smaller one. The modification consists in having a larger radius of curvature than the preceding electrode, so that each of the electrodes is provided with a continuous spherical shape 61. This second electrode 64 is or has semi-spherical surfaces around the tube axis between the first electrode 61 and the lamp. In place of the electrode openings 28, 38, the screen 14 is arranged, namely with their convex or 33 in FIG. 1, grids 51, 52 and 53 with the side facing the concave side of the electrode 61. It has spherical surfaces. These grids 51, a small opening 66 around the pipe axis 20, so that 52 and 53 can, for example, from wire grids 30, an electron beam can pass through. To be educated. It is essential that each of these grids is an additional part of this second electrode 64 and has a high permeability for electrodes. The direction towards the screen 14 is preferably a divergent one. When wire grids are arranged, the render channel 67 must therefore be provided. As with the previous openings, most of the surface and the cited embodiments, the spherical terwires comprise the least part of them. Since 35 electrodes of this embodiment have a high permeability factor such that they have a spherical electrical element between them for the electron beams, only a very small proportion of the beams is generated by the grid for deflecting and accelerating electrons. For this purpose, the catches are used so that there are practically no difficulties in connecting electrodes to a suitable voltage source with respect to grid heating or the attenuation 40, which is shown as a battery 68, where the beams exist. In Fig. 2 are represented by the first electrode 61 at a negative potential with lines 54 equipotential lines, how the second electrode 64 lies,
result from the above mentioned potentials when applied to the grid considering the configuration of the electro. It can be seen that the static field, which is caused by the relative potentials of these lines 54, has the same radius of curvature as the electrodes 61 and 64 sit as the electrodes and like the other lines, it can be seen that one enters the field of the electrodes who because they are all on circles with a common Mit- in F i g. 3 shown embodiment, entering center point 29 of the electrodes lie. In Fig. 2, the electron beam 21 of a radial deflection is also located below the lines of force of the electric field which oppose the original deflection which is caused by the electrodes, since the lines of force of the deflecting elec- tron are created. These are shown as dashed lines 56 of the Irish field converging towards the screen 14 which, as can be seen, evenly axis from the first by the radial potential gradient acting on an electrode 26 radially upward from the tube electron beam entering the field run away and directed towards the fluorescent screen, it turns towards the axis of the tube. The rays are deflected, the focal point of the lines being the mean 55 which, through the spherical acceleration point 29, is the curvature of the electrodes. Concerning the electrical and deflection fields of this embodiment, which will act in the field between the electrodes, is such that the beam now enters the tubes 26 and 31, following the in FIG. 2 display axis crosses. The resulting radial radiation ablent lines of force 56 and these lines of force kung is proportional to the original deflection, accelerated along, since the positive pole of the 60 is much larger. It can also be seen that the field is located on the screen 14 of the tube. It shows that with the second spherical electrode 64, which is clearly evident from FIG. 2 that an electron beam, a relatively small radius of curvature and also which passes through the first electrode 26 and into which a relatively small beam opening 6, the electric field enters, which is generally forced to maintain by the electrodes electron beam, is actually radially deflected 65 to follow the lines of force of the electric field, and at the same time accelerated in its direction of travel that it is actually through the electrode opening 66, so that the electrodes are thereby not only focused and thereby generally serve by further acceleration of the beam, but the center of curvature 62 of the Electrodes and

continue in a relatively field-free region within of the channel 67 finally comes into contact with the screen 14. For this purpose, the second electrode 64 and the channel 67 be electrically conductively connected to the screen 14, thereby creating an area that is free from an electric field that the Beam passes through after entering the second electrode 64. In the embodiments described above, in which the electrode is arranged next to the screen of the cathode ray tube, it can also be marked with iq this must be electrically connected. Even with the in F i g. 3 is an electron beam 21, which enters the electric field between the described electrodes is maintained, accelerated against the screen 14 along the deflected beam path and at the same time deflected further radially by the radial potential gradient. In this embodiment the desired goal is thus also achieved in that after the usual deflection in the cathode ray tube a spherical electric field is created in the beam path, which the electron beam further accelerates and deflects, causing this beam with increased energy and with stronger Radial deflection strikes the fluorescent screen.

In Fig. 4, an electrode system is shown which includes three electrodes 71, 72 and 73, which are shown in FIG same sequence between deflectors of a cathode ray tube 19 and the screen 14 are arranged. As with the embodiments of FIG. 1 and 2 are the electrodes 71, 72,

73 here as spherical electrodes or at least with hemispherical surfaces with a common Center on the pipe axis and with symmetrical arrangement of the electrodes around the axis educated. The electrodes are with openings for the electron beam with progressively increasing Size provided to the screen of the cathode ray tube, so as to provide a corresponding passage for the To form electron beam.

In a departure from the previously described embodiments, this embodiment is about the opening in the first electrode 71, which is located directly next to the deflection devices 19, a thin film 74 is provided. This film 74 lies on the spherical surface of the electrode and forms its hemisphere with the electrode. This movie

74 consists of a material which emits secondary electrons after being bombarded by primary electrons. The film 74 is preferably designed in such a way that from its convex side for each electron, which contacts the concave side of the film, a plurality of electrons are emitted, one such emission takes place directly from the point of impact of the primary electron through the film. A distracted one Primary electron beam of the cathode ray tube, which has the film 74 on its concave side hits, causes an electron beam 76 of secondary emitted electrons on the convex side of the Film 74, which secondary electrons then pass through a spherical field created by the electrodes 71, 72 and 73 is maintained, can be accelerated. Because the secondary electrons on the convex side of the film 74 directly opposite the point of impact of a primary electron on the are emitted concave side of the film, the secondary electron beam 76 forms practically one Continuation of the primary beam, but consists of a much larger number of electrons. Suitable electrical connections of the electrodes 71, 72 and 73 with suitable points of a voltage-dividing Resistor 77, which lies between the poles of a power source, such as the battery 78 is shown serve to generate a spherical electric field symmetrically about the pipe axis 20 the same way as in connection with Fig. 1 was explained to generate. It can be seen that the spherical field as defined by electrodes 71, 72 and 73 of FIG. 4 is generated on the same Way, as above in connection with F i g. 1, acts and an additional electron beam acceleration causes, thereby significantly amplifying the radiation energy and continues to additionally the Beam deflects proportional to the size of the original deflection as it is deflected by the deflectors 19 of the cathode ray tube is achieved.

A major advantage of the embodiment according to FIG. 4 is that by using a secondary emitter in the beam path results in a substantial increase in the beam current. It The primary electron beam of the cathode ray tube does not need to have a high current intensity, since the gain by the secondary emitter 74 is sufficient to provide a secondary beam 76, its Current density is much greater than that, as it is available in conventional cathode ray tubes.

When testing a cathode ray tube with the electrodes described has during operation and the experiment show that it has a sensitivity which is several tens of times higher than the more popular cathode ray tubes. It has been found that a suitable ratio of the radii of the first and last electrodes is about 5: 2. In addition, there is an advantage in that the deflection sensitivity is also achieved with a high end beam energy can be increased significantly, since the deflection is largely independent of the end potential. It should also be noted that an additional focusing of the electron beam by suitable regulation of the relative potentials between the electrode system and the electron source including the electron beam source mentioned above and primary electron lens can be achieved.

Claims (5)

Patent claims: 1. Cathode ray tube with an electron gun, a deflection system, a luminescent screen and arranged between the deflection system and the luminescent screen Means for increasing the deflection angle of the electron beam, characterized in that that the means for increasing the deflection angle of the electron beam from several arranged one behind the other in the direction of the beam and at potentials that are higher with increasing distance from the deflection system Spherical or hemispherical electrodes exist, which have a common have the center of curvature lying on the tube axis. 2. Cathode ray tube according to claim 1, characterized in that the convex sides of the electrodes face the screen and that the common center of curvature of the 609 608/301 Electrodes is at a distance from the deflection means. 3. Cathode ray tube according to claim 1 or 2, characterized in that each of the openings the electrodes are provided with a grid (Fig. 2). 4. Cathode ray tube according to claim 1 or 2, characterized in that the opening of the electrode (71) closest to the deflection means on the convex one facing the screen Side is provided with a secondary electron emission capable film (74), which has a larger number of electrons emitted than hit the concave side (Fig. 4). _a 5. Cathode ray tube according to one or more of claims 1 to 4, characterized in that indicates that three electrodes are provided. 6. Cathode ray tube according to claim 1, characterized in that the concave sides of the Electrodes are facing the screen (Fig. 3). 7. Cathode ray tube according to claim 6, characterized in that at least one of the Electrodes is almost spherical. 8. Cathode ray tube according to claim 6 or 7, characterized in that the dem The electrode facing the screen has a funnel-shaped extension that opens towards the screen having. Considered publications:
German patent specification No. 938 862. 1 sheet of drawings 609 608/301 7.66 © Bundesdruckerei Berlin