DE2111438A1 - Cathode ray tubes for point-by-point representation - Google Patents

Description

Cathode ray tube for point-by-point display

Cathode ray tubes admittedly have numerous advantageous properties that make them suitable for universal use all possible uses for the visualization of more diverse Have made appearances possible, but they show disadvantages when they are used for the representation of Characters, such as the alphanumeric representation of digits and letters, should be used.

These disadvantages arise in particular from the fact that:

- the deflection given to the electron beam has essentially an analogous character, i.e. is continuous with the control signals applied to the deflection elements changes;

the length of the tube is of the order of magnitude of the diagonal of the usable part of the screen.

The aim of the invention is to provide display cathode ray tubes, in which these disadvantages are eliminated.

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According to the invention, a cathode ray tube is rait one Vacuum flask, of which at least a portion is translucent is, and in its interior an electron beam system and a collecting electrode are arranged, the electron beam system at least one cathode and has a control electrode, characterized in that the cathode has a surface of elongated shape, which is covered at intervals with small areas of an electron-emitting material that the control electrode has electrically isolated eyelets, which control the independent control of each of the small planes coming emission allows two additional electrodes are provided which enclose the cathode over its entire length and are essentially parallel to the direction of propagation of the electron beam system generated electron beam extend that the one additional electrode is translucent, before the translucent Section of the piston is arranged or coincides with this and on that of the other additional Electrode facing side with a katodoiuinineszierenden Material is covered, which in turn on the side facing away from the other additional electrode with a thin, translucent conductive film is coated, while the second additional electrode isolated from each other parallel carries conductive strips, and that means for the separate application of voltages to the öeen of the control electrode and are provided on the strips.

The objection could be raised that the dissolution the cathode ray tubes with point-by-point display according to the invention less well than with the classic cathode ray tubes is, in which coherent traces of light are obtained on the screen in general; in reality But this is not a real disadvantage, because the resolution of these tubes is in most cases

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unnecessarily large for the requirements of observation.

The invention is described below by way of example with reference to the drawing. In the drawing show:

1 shows a schematic overall view of a cathode ray tube according to the invention,

Fig. 2, 3, 4, 5, 6, 7 top views or side views the components of the tube of Fig. 1,

Fig. 8 is a diagram for explaining the operation of the tube 1 in a section through a plane perpendicular to the largest dimension of the tube,

9 shows a practical embodiment of part of the in Fig.1 schematically represented cathode ray tube and

Fig.10 the other part of the cathode ray tube from Fig.9

1 schematically shows an overall view of a cathode ray tube according to the invention. In the embodiment shown, the tube contains six electrodes A, B, G, D, E and Q. It is obvious, however, that if one or more electrodes could easily be omitted or added, as long as this does not fundamentally change the principle mode of operation of the tube.

In Fig. 2, 3, 4, 5 the electrodes A, B, C, and D, respectively, are from Fig. 1 shown in a top view for an observer located above the tube, while in Fig. 6 and 7 the electrodes E and F are shown in front view for an observer located between the electrodes.

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The dimensions of the various components are in these Figures chosen according to the requirements of the clear representation, regardless of the real size.

The electrode A (Fig.2) consists of a flat conductor strip 1, for example made of tungsten, on which at regular intervals small equal squares or spots 2 made of an electron-emitting material are attached, for example from one of the well-known cathode oxides.

When the tape 1 is heated by passing a current through it becomes, the spots 2 may emit electrons under certain conditions, and therefore they will hereinafter referred to as cathodes.

The electrode B (Fig. 3) consists of a flat conductor strip 3, for example from a non-magnetic nickel alloy, which has a series of square openings whose Number is equal to the number of spots 2, and which are substantially the same size and spacing «Te have this

The electrode C (Fig. 4) consists of a flat insulating Band 5 », for example made of ceramic, in which square openings are made, the number of which is equal to the number the patch is 2, and which are arranged at the same intervals as this. These openings are made of conductive eyelets 6 framed, delimiting the square openings that are as large as the spots 2 on the electrode A and the openings are in the electrode B; the connections of the eyelets 6 are shown at 7 «

The electrode D (Fig, 5) is exactly the same as the electrode B, it consists of a flat conductive tape 8 with openings

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When assembling the electrodes A, B, C, D are arranged parallel to each other and adjusted so that the holes of electrodes B, C, D in line with spots 2 of electrode A in the direction perpendicular to electrode A. lie.

The electrode E (FIG. 6) is an insulating plate 10, for example made of glass, which in the example of FIG. 1 is directed perpendicular to the electrodes A, B, C, D and on one side conductive coatings 11 in the form of parallel , carries equally spaced strips, the long side of which is parallel to the plane of the band A. Ä

These conductive strips have external connections 12. The side of the electrode E igt which carries these coatings facing the electrode F.

The electrode F (Fig.7) consists of a flat, translucent one Plate 13 », for example made of glass, which is parallel to. the plate E arranged and on this Electrode E facing side completely, with a transparent conductive coating 15, for example is covered from tin oxide, which has an outer connection H, and on which a cover 16 made of a JcatoiolumineszLerenden material is appropriate. The manufacture of the electrode F as well as that of the other electrodes "

corresponds to the state of the art, which is why it is not discussed in more detail here.

The number of spots 2 on the electrode A and more corresponding openings in the electrodes Bj C, D, which, for the sake of clarity, is limited to a few in the drawing, is in reality much larger, for example 70, and the number of metal strips 11 of the electrode E is 250, for example.

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The cathode ray tube described operates in the following Manner, whereby it is to be assumed that the specified voltage values are only to be regarded as an example and are also essential can be chosen differently.

All points of electrode A are brought to the same potential, which is subsequently referred to as zero potential or reference potential is seen·

The electrode B is permanently at a positive potential of a few volts with respect to the electrode A.

The conductive eyelets 6 of the electrode G are dependent a program that depends on the use of the tube, sometimes to a voltage V ^ from +30 to +50 volts and sometimes placed on a negative voltage of a few volts.

The electrode D is permanently connected to a positive voltage V _D of a few 100 volts, for example.

If the voltage applied to an eyelet 6 is positive and is equal to the previously indicated positive voltage VqJ ₁ , while a current flows through the electrode A, an electron beam goes from the spot 2 of the electrode A located under the relevant eyelet 6 through the corresponding one Hole 9 of plate D in the space between electrodes E and F.

On the other hand, if the voltage applied to an eyelet 6 is slight becomes negative, the emission of the corresponding spot 2 stops.

The conductive coating 15 of the electrode F is continuously held via the terminal 14 at a potential which is essentially equal to the potential V _D.

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In contrast, the conductive strips 11 applied to the electrode E are sometimes brought to the voltage V _D according to a program that is linked to the program relating to the eyelets 6, and sometimes to a voltage which is less than the voltage _{by an amount V GC} V _D , i.e. to the voltage V ^ - Vqq

If it is assumed that all the conductive strips 11 of the electrode E _{would be brought to the potential V 33} at the same time, the electron beam emitted by a spot 2 would with a corresponding bias V ₀ ^ of the associated eyelet 6, which in the example chosen between +30 and + 50 volts, go through the space between the electrodes E and F parallel to them, since then this space would practically be an equipotential space due to the equality of the voltages of the two electrodes.

If this is not the case, however, the ^{electron beam coming from a 3 1} IeCk is deflected towards the electrode F when it arrives at the level of a strip 11 which is brought to the previously mentioned furnace Y _D -V _ÖG , because then there is a positive difference between the voltage V _{D of} the electrode F and the voltage of the strip concerned. When all layer 16 of electrode F hits, the electron beam then excites the luminescence of a point on this layer.

This is shown in Fig. 8, as schematically shows the mode of operation of the tube of Fig. 1, the Deuts Hch Ice It being exaggerated because of the conductive strips 11 and their number being limited to 4. This figure shows the course of the electron beam 17 which comes from a spot 2, not shown, and passes in front of the three lower stripes 11, which are brought to the voltage V _33. The arrow f shows the direction in which the electron beam is deflected when it is near the fourth stripe

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arrives brought to the voltage Vjj-Vqq.

The display of a point of light on the luminescent layer 16 is obtained in that the eyelet 6 and the strip 11, which define this point according to the diagram of FIG. 8, are switched to the voltages V _cl and Vj) -VqQ.

The voltage Vq-t is called the Zeilin control voltage, and the voltage Vq “column control voltage.

In operation, the sliding eyelets 6 of the electrode G and the conductive strips 11 of the electrode E are with one Switch connected, which makes it possible to switch to the eyelets 6 applied voltages from the value V ^^ to a negative; "Tension, of a few volts and to bring the voltage applied to the strips 11 from the value Vp to the value V-p-V ™, depending on the point on the luminescent layer should be used to light up.

The voltage V ^ is usually a few tens of volts.

This point should be emphasized because it turns out to be very important for the invention.

As a result of the use of a large number of cathodes in the form of the spots 2 of Fig.2, which are described for the Tube is characteristic (namely as many cathodes as there are rows). the same brightness on impact of the electron beam onto the cathodoluminescent layer 16 (FIG. 7) under otherwise identical conditions with a very much smaller electron beam acceleration voltage can be obtained than with the classic cathode ray tubes.

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Hun, this acceleration voltage is nothing other than the column control voltage Vq ₀ , as is apparent from the above description; In the case of the cathode ray tubes described, this voltage can be limited to a few tens of volts, i.e. to a value that is compatible with small switches made of discrete formwork elements and even with switches made of integrated circuits, to which there is an increasing trend in the field of display technology.

Another advantage of the invention is that the scope of the cathode ray tubes according to the invention because of the angled course of the electron beam between the cathode and the cathodolurainescent layer is considerably smaller than with the classic cathode ray tubes, the space requirement can even be quite extraordinary be reduced, because it is practically only due to the dielectric strength between the electrodes E and P. limited, and from the above it can be seen that this voltage does not exceed a few tens of volts « It goes without saying that in this case the electrode A (Pig .1) and consequently the spots 2 (Fig.2) in the same Proportions need to be reduced.

In the above description, it has been assumed, for the sake of convenience, that the spots on the electrode A and consequently the openings in electrodes B, 0 and D at evenly spaced intervals on the electrodes are arranged. But it is obvious that the distances between the individual spots or between successive groups of spots are variable could be. This also applies to the conductive strips of electrode E.

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Furthermore, it has been assumed that an electrode B is present opposite the electrode A on a small positive potential. However, such an electrode is not essential for the operation of the tube necessary. The tube may just as well contain no such electrode, or it may, on the other hand, contain several others Electrodes included, if seen from electron optics Reason seems appropriate.

Finally, it should be emphasized that a trap electrode, which has not been mentioned so far because it belongs to the general state of the art in cathode ray tubes, is absolutely necessary in order to capture the electrons which in the absence of the voltage Vqq without deflection from the electrode A to the opposite one End of the tube would go. This fan electrode could quite simply be an additional conductive strip which is attached to the electrode E on the other side of the last strip 11 and brought to a potential which is somewhat higher than the potential V ₀ .

9 and 10 show in an exploded view a practical embodiment of a cathode ray tube of the type described, in which the electrodes E and F form part of the tubular bulb. In the example shown there is the Tubular flasks made of 2 U-shaped parts, both made of glass, for example, the electrodes E and F are made aas the legs of a U-shaped part, which the strips 11 on the one hand and the layers 15 and 16 on the other wear, while the web of the other U-shaped part carries the electrodes A, C and D. The two separated manufactured U-shaped parts are along their circumferences a and b by any known method closed vacuum-tight "

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The attachment of the electrodes to their support and the formation of the electrode connections also result from the prior art, are only shown schematically in Fig.10.

Claims

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Claims (1)

^'12 "211U38 Claims Cathode ray tube with a vacuum piston from the at least one portion is translucent, and inside an electron beam system and a target electrode are arranged, wherein the electron beam at least has a cathode and a control electrode, characterized in that the cathode has a surface of elongated Has shape covered at intervals with small areas of an electron emitting material is that the control electrode has electrically isolated eyelets, which the independent control of each of the Emission coming from small areas enables two additional electrodes to be provided, which form the cathode enclose their entire length and are essentially parallel to the direction of propagation of the electron beam system generated electron beam extend that the one additional electrode is translucent, before the translucent Section of the piston is arranged or coincides with this and on that of the other additional The side facing the electrode is covered with a cathodoluminescent material, which in turn is on the other side The side facing away from the additional electrode is covered with a thin, translucent, conductive film while the second additional electrode carries parallel conductive strips insulated from one another, and that means for the separate application of voltages to the eyelets of the control electrode and to the strips. Cathode ray tube according to Claim 1, characterized in that that the electron beam system sequentially a cathode in the form of a flat rectangular metal strip, which in 109839/1205 -13-211H38 Spaced elements made of an electron-emitting Material carries, a flat rectangular electrode arranged parallel to it made of insulating material with at intervals arranged holes bordered by metallic eyelets and a flat rectangular one arranged parallel to them Metal electrode with spaced holes contains that the holes in the electrodes are essentially the the same size and the same spacing as the elements on the cathode that the electrodes have relative to each other are arranged so that the elements and the holes perpendicular to the metal strip, the cathode are each in a line lie that the two additional electrodes are two planes arranged perpendicular to the metal strip of the cathode Are plates, and that the conductive strips on one additional electrode are rectangles, the long sides of which lie parallel to the long sides of the metal strip of the cathode. 3. cathode ray tube according to claim 1 or 2, characterized in that that the additional electrodes are components of the tubular bulb. 4. Display device with a cathode ray tube after a of claims 1 to 3, characterized by devices for applying certain potentials to the cathode and to the thin conductive PiIm, and means for applying separate potentials to each of the eyelets and to each of the conductive strips, with the potentials applied to the eyelets sometimes higher and sometimes lower than the cathode potential and the potentials applied to the conductive strips are sometimes lower than the potential of the thin conductive one Films and sometimes equal this potential. 109839/1205 Blank page