DE1954451C3 - Beam generator system for cathode ray tubes - Google Patents

Description

The invention relates to a beam generator system for cathode ray tubes in the preamble of Art.

In known beam generator systems of this type, there are two perforated disk-shaped electrodes made of metal, the separating layer between these by a thin plate or sheet of electrically conductive Material is formed. The electrodes and the plate or film are separately manufactured components that can be assembled in the classic way that is usual for vacuum tubes. This is because of the required high accuracy very labor-intensive and is encountered when the jet generator system is very fts should be small, special difficulties. Added to this is the disadvantage of reducing the mutual The electrical voltage load capacity of the known beam generators is getting smaller and smaller systems; but it depends precisely on the level of tension between the grid and the neighboring anode to a large extent the efficiency of the cathode ray

turn off.

The invention is based on the object, eil beam generator system in the preamble of An Proverb 1 designated type to create that in particular re also in small dimensions with relatively little effort while achieving a good chip voltage load capacity can be produced.

This object is achieved according to the invention with the jet generator system characterized in claim 1. Due to the formation of the two perforated disk-shaped electrodes as coherent layers of differently doped semiconductor material, the usual techniques for producing semiconductor components can be used for the production of the two electrodes, which allow very rational production even in very small dimensions under compliance with the greatest possible Allow accuracy. In this way, the negative layers, including the separating layer, can be produced in one piece in one process and then together .1. B. be provided by etching with a single through hole, which automatically aligns exactly in all layers. Since the anode has a higher electrical potential than the grid in order to achieve the desired focusing and acceleration effect, the two differently doped layers are loaded in the reverse direction. This allows high electrical field strengths and, despite a very small thickness of the separating layer, which in the simplest case is formed solely by the depletion layer formed when the pn junction formed by the two layers is loaded in the reverse direction, enables a high voltage to be applied between the grid and anode.

The invention is illustrated more schematically below with reference to the hand Drawings of several exemplary embodiments explained in more detail.

F i g. 1 is a longitudinal section through a cathode ray tube with a conventional electron gun system, the usual deflection devices being omitted;

F i g. Fig. 2a is a perspective view showing the grid structure of the invention, which essentially a portion of the electron gun system of FIG. 1 corresponds to;

F i g. 2b is a section along the line Ι-Γ in FIG. 2a;

F i g. 3a is one of the FIGS. 2a shows a corresponding illustration and shows a modified embodiment;

Fig. 3b is a sectional view taken along line ΙΙ-1Γ in Fig. 3a;

F i g. 4 is a block diagram of the grid structure of FIGS. 2a and 2b provided electron gun system;

F i g. 5 is one of the F i g. 4 corresponding representation with a grid structure according to FIGS. 3a and 3b;

F i g. 6a is a block diagram of another modified grid structure;

F i g. 6b is one of the FIGS. 6a corresponding illustration showing a further modified grid structure clarified;

F i g. 7a is a longitudinal section through a further modified grid structure;

F i g. 7b is one of the FIGS. 7; i corresponding representation, which shows a further modification of a lattice structure;

1 954 45i

F i g. Figure 8a is a top plan view of a grille structure for use in a color television receiver of Figure 8a Mask type;

F i g. 8b is a partial view taken along line ΙΠ-11Γ in FIG F i g- 8a.

In FIG. 1 is a typical cathode ray tube 10 with a conventional electron beam generator system shown with the deflectors omitted. The beam generator system shown on the left is provided with several metal electrodes, which are divided into two groups according to their task "A" and "ß" are subdivided. Has a group "/ \" a cathode 11, a first grid electrode 12 and a second electrode 13 as an anode, which are essentially have centrally located openings. The group "A" as a whole does not only act as a generator of an electron beam, but also as a focusing device, which has a first beam focusing effect by crossing brings about. The group "β" has a third, a fourth and a fifth anode electrode 14, 15 and 16 and acts to further focus and to post-accelerate the electron beam.

The operation of the group "Λ" is such that the first grid electrode 12 has a control of the strength of the to be emitted electron beam, while the second anode electrode 13 the electron beam pulls out of the cathode 11 or attracts from this. This is because in a conventional Electron gun with a grounded cathode, the first grid electrode 12 usually with a variable negative Potential is applied while the second anode electrode 13 is held at a positive potential will. In this way, the emission strength of the electron beam is controlled by the first grid electrode 12 and by the second anode electrode 3; 13 pulled out.

Such a control of the electron beam is not only attributed to the mask effect of the openings, but also the effect of the recoil forces exerted by the electron beam and the first grid electrode 12 have the same polarity, i.e. these two are on a negative potential. On the other hand, the crossing of the first beam focusing effect is made possible by the Potential field induced that is axially symmetrical between the first grid electrode 12 and the second anode electrode 13 is built.

The F i g. 2a and 2b and FIGS. 3a and 3b show a first and a second embodiment of the invention. For the sake of simplicity, it is assumed that the group "A" according to FIG. 1 in the following figures has essentially the same grid structure, so that the parts corresponding to the parts in FIG. 1 correspond to the same Reference symbols are assigned.

In the F i g. 2a and 2b, the grid structure has three concentric disk-shaped layers 17, 18 and 19, d. H. a first grid electrode 17, a separating layer 18 and a second anode electrode 19, each having a substantially circular opening or in the middle have a circular hole of suitable inside diameter. The first grid electrode 17 lies with their end face near the cathode 11 and at right angles / around the path of the electron beam. The first and the / wide electrodes 17 and 19 both consist of semi-conductor material, which in the case of layer 17 is p-conductive and fts in the case of layer 19 is η-conductive. A resistance material, used as the separation layer 18 is firmly sandwiched between the two electrodes 17 and 19 so that the layers, i.e. H. their central openings with each other (Juchten. In the practical Production, the grid structure is made as an integral body and then etched in the middle, to form the aligned opening of suitable diameter.

During use, the first grid electrode i7 and the second anode electrode 19 are connected to a DC voltage source 20 a voltage is applied so that a high potential field is built up in the interior of the opening will. As a result, several electrical lines of force 21 are formed symmetrically to the separating layer 18, which bend or focus the emitted electron beam inward, creating the crossover effect caused. Thus, the filter structure "A" acts as such as an electron beam focusing device, such as it is used in a small electron gun system.

According to FIGS. 3a and 3b, a first grid electrode 17 consists of a p-conducting semiconductor material, while a second anode electrode 19 consists of an η-conductive semiconductor material. With this modification the separation or barrier layer 18 is a depletion layer. Accordingly, these form three Layers 17, 18 and 19 as a whole have a pn junction, in which the two electrodes of opposite conductivity are in electrical contact with one another.

When from a DC voltage source 20 to the p-conducting and η-conducting layers 17 and 19, a reverse bias is applied and the thickness of the depletion layer 18 is not negligible compared to the dimensions of the openings, then becomes corresponding to the first embodiment according to FIGS. 2a and 2b built up a potential field in the holes, whereby a beam focusing effect is brought about. It is therefore of a more detailed nature Discussion of the operating mode has been refrained from.

In Fig.4 there is a practical circuit of one Beam generator system with a grid structure "A" according to FIGS. 2a and 2b shown. From a changeable one DC voltage source 22 is applied to the grounded cathode 11 and the first grid electrode 17 to a variable Signal voltage applied, which is the strength of the emitted depending on the applied signal Electron beam 23 controls. A constant DC voltage source 24 is on the other hand to the cathode 11 and a second anode electrode 19 applied a predetermined voltage, the electron beam 23 withdraws from the cathode 11. It follows that the man controlled and focused in this way Electron beam 23 accelerated through the remaining conventional anode electrodes 14, 15 and 16 and focused to an image on the faceplate (not shown) of the cathode ray tube.

In FIG. 5 is another modified grid structure made clear. In this case, from the variable DC voltage source 22 to the first grid electrode 17 made of p-conductive semiconductor material and to the second anode electrode 19 made of η-conductive semiconductor material a varying .Signalspannung applied as a reverse bias, which the emission strength of the electron beam 22 depending on the applied signal. Furthermore, the constant DC voltage source 24 between the grounded cathode 11 and the second anode electrode 19 a predetermined voltage applied, which holds the second electrode 19 at a positive potential and from the

Cathode 11 controlled by the first electrode 17 Electron beam pulls.

If the cathode is grounded as usual, it is sufficient if the first grid electrode 17 and the second anode electrode 19 are held at a negative or positive potential. There can be numerous variations can be made without deviating from the principle described above, as the electrical Connections are affected.

In general, the control accuracy of the electron beam in cathode ray tubes depends mainly on the flight length of the electron beam and its speed, which is determined by the potential applied to the anode electrodes. It is known that the depletion layer of a pn junction is inherently limited in its thickness. Is therefore intended to fly longer than it is given by the thickness of the depletion layer of the electron beam under the Fokussiereinfluß, the barrier layer may be thicker provided that the pn junction in place as g in conjunc- u> tion with the F i. 3a and 3b and 5, a pin or pnpn junction is used.

Such modified embodiments are illustrated in FIGS. 6a and 6b. According to FIG. 6a in which a pin junction is used, the grounded ² S separation or barrier layer or an i-type layer 18 to the positive terminal of the variable DC voltage source 22 is connected. The first grid electrode 17 made of p-conducting semiconductor material is connected to the negative terminal of the source 22 so that it is held at a negative potential which varies as a function of the applied signal. A predetermined voltage is applied to the intrinsically conductive layer 18 and the second anode electrode 19 made of an η-conductive semiconductor material from a constant DC voltage source 24, which voltage keeps the second electrode 19 positive. If according to FIG. 6b, on the other hand, a pnpn junction is used, the separating or barrier layer corresponds to another inner pn junction 18. Its η-conducting and p-conducting layers are kept at the same ground potential as the cathode 11. The other electrical connections correspond to the case where a pin junction is used.

In the F i g. 7a and 7b show further modifications of the invention. In both cases, the Cathode 11 and the first grid electrode 17, a high resistance layer 25 with a substantially i in the middle located circular opening fes arranged. The resistance layer 25 sits on the dei Barrier layer 18 on the opposite side firmly on the first electrode 17. In this case, the grid can be on build according to the invention integrally with the cathode 11 be placed so that a more precise and easier alignment can be achieved. In the case of FIG. 7a isl the barrier or separation layer is a layer of high resistance material, in the case of FIG. 7b the depletion layer a pn junction. The latter modification is particularly applicable in cases where de a pin or pnpn junction is now used in the grid structure. Thus delivers the firmly connected to the cathode Lattice structure satisfactory accuracy and correct cannon alignment.

The grid structure according to the invention in the various embodiments can also be used in practical multi-beam electron tubes, for example in color television receivers of the mask type, as shown in FIG. 8 shown. In this case it is assumed that the grid structure has a pin junction. The letters R, G and B, which are assigned to the individual grid structure units, correspond to the three elementary colors, ie red, green and blue in color television. The grid structure units R, G and B sit on a common substrate 26, which corresponds to the n-type semiconductor material, and are arranged, for example, at the tips of an isosceles triangle of suitable size.

For the practical production of such a grid arrangement, first of all, at predetermined points of the η-conductive pad or the second anode electrode z. B. formed by diffusion eigenleitendc layers, on which the associated p-conductive layers or first grid electrodes are then formed by a corresponding method. After this process has ended, central openings are formed in the layers obtained for the passage of the electron beams representing the color signals, namely red, green and blue. In these arrangements, if variable signal voltages are applied as reverse bias voltages to the common second electrode and the respective first electrodes, all of the grid assembly units R, G and B can be controlled independently of one another.

For this purpose 3 sheets of drawings

Claims (7)

Patent claims: 1. Beam generator system for cathode ray tubes with two behind the cathode in the direction of the beam Perforated disc-shaped electrodes as a grid and to be held at a positive potential opposite this Are arranged between and in contact with which a separating layer with an anode the hole which is coincident with the holes of the electrodes, characterized in that that the two electrodes by two layers (17; 19) made of p-conductive for the grid and for the Anode η-conductive semiconductor material are formed. 2. Beam generator system according to claim 1, characterized in that the separating layer (18) one of the two adjacent layers (17, 19) made of semiconductor material Depletion layer is. 3. Beam generator system according to claim 1, characterized in that the separating layer (18) has a is intrinsic layer. 4. Beam generator system according to claim 1, characterized in that the separating layer (18) is a pn junction, the two layers of which with the two grid and anode-forming layers (17; 19) form a pnpn structure and are electrically connected. 5. beam generator system according to claim 1, characterized in that the separating layer (18) is a layer of high resistance material. 6. Beam generator system according to one of claims 1 to 5, characterized in that the one another adjoining layers (17; 18; 19) with the cathode (11) via a further one on which the grid Forming layer (17) applied layer (25), which consists of high resistance material and a with the holes of the other layers has congruent hole, are connected. 7. See the beam generator system according to one of the Ap.spr. 1 to 6 for multi-beam tubes with grid and anode for each beam, characterized in that the layers forming the anodes are combined to form a uniform η-conductive substrate (26) are, in which the p-conductive layers forming the grids are separated with a separating layer each are embedded between them and the substrate.