KR810001809B1 - Picture display tube - Google Patents

Abstract

The picture display tube includes an electrode system(4) generating an electron beam directed to a display screen(8). An electrically conductive layer(13) extends between the screen and the electrode system over the envelope inner surface. A resistive layer(14) is situated near the electrode system. A high voltage contact(15) in the envelope between the screen and electrode system is connected to the conductive layer. A getter(18) is mounted on a resilient metal connection strip(19) detachable held in the envelope by a pin and slot connection. The pin projects internally from the tube wall and having an enlarged head and neck.

Description

Video display tube

1 is a cross-sectional view of a color television display tube to which a getter according to the present invention is fixed.

FIG. 2 is an enlarged view of how the getter is fixed in the display tube shown in FIG.

3 and 3a and 3b are cross-sectional views of an embodiment of a connecting member according to the present invention fixed to a high voltage terminal.

4 is a schematic diagram of a getter having a connecting strip according to the present invention.

5 is a cross-sectional view of an embodiment of a connecting structure according to the present invention.

6 is a cross-sectional view of a connecting member for forming a component with a high voltage contact.

7 and 7a and 7b is an auxiliary mechanism for fixing the getter according to the present invention to the tube.

The present invention relates to an electrode system for generating an outer shell comprising a display screen and at least one electron beam projected onto the display screen and at least one positioned between the electrode system and the display screen over at least the inner surface of the shell and located near the electrode system. A getter is provided in the shell between the electrode layer and the display screen, the electrically conductive layer consisting of the electrical resistive layer, and the getter fixed to the connecting member protruding inwardly from the pipe wall by a high voltage contact and an elastic metal strip electrically connected to the conductive layer. A video display tube is included.

Such image display tubes are described in British Patent Specification No. 1.226.728. Due to the very large voltage difference between certain electrodes of the electrode system, an electrical flashover can occur, which is associated with a current which rises rapidly and reaches a large value in the tube. This results in particularly damaging inductive or capacitive coupling of semiconductor elements in the electronic circuitry of television receivers. A known method of preventing such damage is to provide an electrical resistive layer in the inner wall portion of the light envelope near the electrode system. However, this method requires that the getter, which is normally connected to the electrode system by a metal strip, should be fixed in the tube and otherwise prevent the gettering material evaporated from the getter by heating from being deposited on the resistive layer to prevent shorting of the resistive layer. Must be prevented or the layer is shorted by a metal strip.

In FIG. 3 of the previously known British specification, the getter is stuck to a high voltage contact. The connection is carried out before fixing the glass cone to the glass window of the tube. The advantage of this method is that the getter is assembled into the tube in a tube manufacturing process where the getter's connection location can be achieved very easily. The harmful effects of gas or evaporation gas on the getter during the continuous manufacturing process of the tube can be avoided by using protective getters or chemically resistant getters.

The method described in the British patent specification is used only when there is no need to assemble the getter in the tube after it is secured to the cone and window. However, this assembly method is necessary in black and white display tubes, and also exists in color display tubes when the outer shell is stored for some time after the window and the cone are fixed together. In such a case, it is preferable not to provide a getter to the shell. Moreover, this need exists when a new getter must be provided during repair of the tube.

It is an object of the present invention to provide an image display tube which is suitable for inserting a getter through the neck of the tube and is provided as a connecting member that can be easily fixed as well as easily detachable at a position away from the electrode system in the tube.

According to the present invention, the image display tube of the type described in full text has a connecting member portion protruding from the tube wall having a gradually widening end having the largest diameter D and the smallest diameter d, and the metal connecting strip of the getter being the largest diameter D. Having a larger diameter first hole, the first hole cooperates with a second hole of diameter A in the manner of D > A > b > It is characterized in that it is connected to the second hole through the passage of the width b.

Fixing of the getter is accomplished by inserting the wider end of the connecting member through the first hole of the getter's connecting strip and moving the connecting strip in its longitudinal direction in such a way that the second hole of the connecting strip cooperates with the wider end of the connecting member. Is executed. The engagement is thus locked at the place where the connecting strip presses the tube wall on either side of the second hole and as a result of the elasticity of the strip the strip is pressed against the widened end of the connecting member in the region of the second hole. Good coupling between the connecting member and the connecting strip is achieved by the weak elasticity of the strip. Therefore, this coupling does not require strong elastic force. As a result of this, the aid for providing the getter in place can be of an extremely simple construction, minimizing the possibility of damaging the tube while providing the getter. Also, when repairing a tube, the removal of the getter can be carried out extremely simply without the need for a large force with the coupling machine described above.

The gradually widening end of the connecting member may have a number of forms. The ends may be spherical, conical or pyramid shaped. Furthermore, in the embodiment according to the present invention, the connecting strip has a portion deepened in the region of the second hole so that the redundant talking of the coupling is obtained. The shape of the deeper portion corresponds to the shape of the gradually widening end of the connecting member.

In this latter case, as a connecting member widened in the form of a pyramid, the strip may be locked against rotation about the connecting member. Locking against rotation is replaceable by providing a widening end of the connecting member with at least one flat portion that cooperates with the straightness of the second hole.

The connecting member is preferably fixed to the high voltage contact provided on the pipe wall, so that the connection member to the getter is obtained by the insertion of the high voltage contact. According to a particular embodiment of the present invention, the connecting member having the high voltage contact constitutes one thin film material component.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The tube shown in FIG. 1, which is a vertical sectional view, comprises a glass shell with display window 1 and cone 2 and neck 3. Electrode system 4 which generates electron beams 5, 6 and 7 of the world is located in neck 3. Electron beams 5, 6 and 7 in this case consist of a plurality of phosphor strips which are generated in a plane perpendicular to the plane of the drawing and which emit light in red, green and blue and are provided inside the display window and are parallel to the plane of the drawing Projected on screen 8. The electron beams 5, 6 and 7 are deflected across the display screen 8 by means of a plurality of deflection coils 9 arranged coaxially around the observation on the way to the display screen 8 and also parallel to the plane of the drawing and have a long hole 11 Pass through the color selection electrode 10 consisting of.

The three electron beams 5, 6 and 7 pass through holes 11 at small angles to each other and are projected onto only one colored phosphor strip. In addition, the tube is equipped with an internal screen cone 12 which blocks the electron beams 5, 6 and 7 from the geomagnetic field.

The inner wall of the tube is covered with an electroconductive layer 13 and the 14 portions extending from the neck-cone transition portion of the neck 3 consist of an electrical resistive material, which is approximately 60% ferric oxide and 10% graphite and It consists of a mixture of 2,50 percent potassium silicate. Layer 13, which can be replaced by an electrical resistive layer, is connected to the high voltage contact 15 installed in the pipe wall, and is connected to the color selection electrode 10 and the display screen 8 via a contact spring 16, and through the contact spring 17 of the electrode system 4 It is connected to the final electrode.

After the tube is vacuumed as is known, a layer of gettering material, such as barium, strontium, calcium, magnesium, for example, is deposited on the tube wall so that the remaining gas remaining in the tube is gettered. In a conventional display tube, a gettering device for evaporating the gettering material by heating is connected to an electrode system directly or by a metal strip. As already explained, this conventional connection method may be required for a display tube having a resistive layer. As shown in Fig. 1, the getter 18 according to the present invention is connected to the tube at a position away from the electrode system 4 by the connecting strip 19.

The getter is fixed to the connecting member bonded to the high voltage contact 15 so that it can be separated by using the connecting structure described in FIG. This figure shows the wall portion of cone 2 where high voltage contact 15 is sealed. The high voltage contact 15 has a connecting member in the form of pin 20 which extends into the cavity of the tube and extends in the form of a cone at its free end and has the largest diameter D and the smallest diameter d as shown in FIG. As shown in FIG. 2, the getter 18 includes a metal holder 21 bonded to the metal connecting strip 19. Strip 19 has a first hole 22 having a size larger than diameter D. The hole 22 connects to the second hole 24 which is smaller than the diameter D but larger than the diameter d through the passage 23. The width of passage 23 is slightly larger than diameter d but smaller than the diameter of hole 24. This is shown in Figure 4, which is a schematic of getter 28 and connection strip 29. Due to the elasticity of the connecting strip 19 bent in advance according to the dashed line 25 (shown in FIG. 2), the strip 19 is formed with respect to the conically widened end of the pin 20 in the second hole 24 zone where the pin 20 and strip 19 join. Apply pressure. The possibility of the rotation of strip 19 relative to pin 20 can be prevented by providing at least one flat portion as shown in FIG. 3 with a dashed line 26 at the widened end of pin 20 and the second straight edge cooperating with the flat portion. It can be prevented by providing it to the hole.

Instead of the conical widened end, other forms are possible. For example, the spherical wide end 27 of the connecting member shown in FIG. 3a or the end 30 widened in the form of pyramid as shown in FIG. 3b. Moreover, the connecting member does not need to be stuck to the high voltage contact. The connecting member may also be inserted independently in the tube wall.

5 shows a getter structure in which the strip strip 39 has a portion 40 deepened in the region of the second hole 44. As a result, the coupling between the connecting strip 39 and the connecting member 41 is additionally locked. Alternatively, the strip 39 includes a first hole 42 connected into the second hole through the passage 43 similar to the structure shown in FIG.

6 shows a high voltage contact 50 with connecting members 51 formed in three dimensions with them. The part is made of thin film material and is also obtained by deep drawing method. This one-piece construction has the advantage that the bonding process, which may damage high voltage contacts, does not have to be performed.

7 shows a possible embodiment of a device in which a getter can be provided in place through the neck of a tube. The device comprises an elastic metal strip 60 having a metal holder 61 provided with a hole 62 extending at one end. The other end of the strip 60 is fixed to a rigid tube 63 with a handle 64. At one end, the traction cable 65 connected to the holder 61 is guided along the strip 60 by the cable guide 66 and the other end is fixed to the handle 67 fixed to the tube 63 to be rotatable. Elastic strip 60 is bent by tensioning cable 65 with handle 67.

In the hole 62 of the holder 61 a stud 68 is arranged about the axis 69 so as to be rotatable. The second towing cable guided along the strip 6) with a slight drive is fixed to a second handle 71 connected to the tube 63 so as to be rotatable at one end and to the stud 68 at the other end. By tensioning the cable 70 with the handle 71, the stud 68 rotates about the axis 69 to release the getter secured to the holder 61.

FIG. 7A shows the position of fixing the getter 28 of FIG. 4 on the holder 61 as the connecting strip 29. FIG. The connecting strip 29 has four alternating edges in which the strip 29 can be tensioned between four studs 72 in the holder 61. In the position shown in FIG. 7A, the getter 28 can be provided in place through the open neck 3 of the family shown in FIG. 1. This is done as follows: The elastic strip 60 of the getter insertion device shown in FIG. 7 is inserted into the neck 3 of the tube beyond the distance the alternating member 73 takes with respect to the open end of the neck 3 of the tube. The ear cable 65 is thus tensioned such that the strip 60 is bent and the holder 61 is moved through the high voltage contact 15 with the connecting member 20. Access to the high voltage contact is made through the slotted cabinet 80 in the magnetic shield cone 12 as shown in FIG. The position 73 of the alternating member on the insertion device is such that the hole 32 provided in the connecting strip 29 corresponds to the position of the connecting member 20 with the strip 60 bent, and thus the wider end of the connecting strip 29 connecting member 20 when the strip 60 is bent. Slide up. The strip 29 is thus moved longitudinally until the second hole 34 coincides with the connecting member 20. In the context of this method, the connecting strip 29 is separated from the holder 61 by the tension of the cable 70 so that the stud 68 rotates and the connecting strip 29 falls apart between the studs 72. Due to the elasticity of the connecting strip 29, the strip presses the gradually widening end of the connecting member 20 in the region of the hole 34. The joining of the strip 29 and the connecting member 20 is thus made in the manner as shown in FIG. 2 or FIG. 5.

The principle of securing and inserting the getter in the tube has been described with reference to a manually operated device. Of course the operation of the device can be simply mechanized. Furthermore, disconnecting the getter's connecting strip from the holder may be separated in a different way from that of stud 68. For example, as shown in FIG. 7B, the holder 90 may consist of two parts 91 and 92 pivoting about the shaft 93. The portion 92 of the holder 90 is inclined in the direction of arrow 94 to separate the getter's connecting strip. As another possibility, the holder may be made detachably by the structure in which the parts 91 and 92 are separated in the longitudinal direction of the holder.

Claims (1)

In an image display tube composed of an outer shell including an display screen (8), an electrode system (4), an electrically conductive layer (13), a high voltage contact (15, 50), and a getter (18, 28), a connection protruding from a tube wall. The ends of the parts 20, 27, 30, 41 and 51 are gradually widened from the smallest diameter d to the largest diameter D, and the getters' metal connecting strips 19, 29 and 39 are larger than the largest diameter D. The first hole 22, 32, 42 having a large diameter is formed, and a gradually widened end of the connecting member is formed through the passage b having a width b provided in the form of D> A> b> d. And 34,44, which can be separated from each other.

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