JPH07249373A - Manufacture of cathode structure of cathode-ray tube and device for use therein - Google Patents

Abstract

PURPOSE:To mass-produce a cathode structure with an excellent electron emission characteristic in a short time at good operability by effectively restraining an electron-emitting material from exuding onto and contaminating the surface of a cathode base, especially at an electron-releasing part, preventing emission of electrons from other than the cathode base, and preventing leaks between cathode electrodes. CONSTITUTION:A first hole 76 and a second hole 78 are formed in the respective portions of a second electrode 74, the second hole 78 being located below and approximately concentric with respect to the first hole 76 and smaller in bore than the first hole 76. A cup 66 to which a cathode base 46 is attached is housed in the first hole 76 with the surface of the cathode base 46 down, and a first electrode 72 is pressed against the cup 66 and a current is made to flow between the first and second electrodes for the resistance welding of the cup to the cathode base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a cathode assembly of a cathode ray tube and an apparatus used therefor.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a cathode assembly of a cathode ray tube, as shown in FIG. 7, a pair of first casings located outside a sleeve 6 in a state where a cathode substrate 2 is housed in a cup body 4. A welding current I is passed between the first electrode 8 and the second electrode 10 located inside the sleeve 6, and the cup body 4
And the upper end of the sleeve 6 is resistance-welded while crimping. The first electrodes 8 and 8 perform resistance welding while caulking the upper end outer circumference of the sleeve 6 at, for example, about 36 points over the entire circumference.

The cathode substrate 2 is impregnated with an electron emitting substance. After this resistance welding, the sleeve 6 is attached to a ceramic disk, and a heater is mounted in the sleeve 6 to form a cathode assembly.

[0004]

However, in the method of manufacturing the cathode assembly according to the conventional example as described above, resistance welding is performed while caulking the entire circumference of the sleeve 6 at about 36 points, which requires too much work time. There was a problem that it was not suitable for mass production. Especially in a color cathode ray tube, three primary colors (R,
G, B) requires three sleeves 6 with a cathode substrate, so that it is required to shorten the manufacturing time of each sleeve 6 with a cathode substrate.

Further, since the upper ends of the cup body 4 and the sleeve 6 are caulked by resistance welding with the first electrodes 8 and 8, the welding tends to be insufficient. If the caulking and welding are insufficient, a gap is likely to be formed between the cup body 4 and the cathode base body 2 or between the cup body 4 and the cathode base body 2. In addition, the welded part may come off due to heat when the electron emitting substance is decomposed and cured or when the cathode ray tube is operated.

When a gap is created in the welded portion, when the cathode ray tube is used, the heat from the heater mounted in the sleeve 6 is not well transferred to the cathode base 2 through the sleeve 6, and the cathode base 2 is efficiently heated. However, there is a problem in the stability of electron emission. Therefore, as shown in FIG. 8A, the brazing material or the metal film 12 is formed on the surface of the cathode substrate 2.
A method has been proposed in which (for example, iridium, ruthenium, molybdenum, or an alloy thereof) is attached, the cup body 4 is covered thereon, and the first electrode 13 and the second electrode 14 are resistance-welded. The first electrode 13 is pressed against the bottom of the cup body 4, and the second electrode 14 is in surface contact with the surface of the cathode substrate 2. According to this method, the brazing filler metal or the metal film 12 is melted during resistance welding, and the cathode base 2
And the cup 4 are connected well. The pressing of the cup body 4 by the first electrode 13 needs only two or three points,
Sufficient welding strength can be obtained.

After that, as shown in FIG. 8 (B), the cup body 4 to which the cathode base 2 is welded is fitted to the upper end portion of the sleeve 6, and the entire circumference or several points of the upper end of the sleeve is laser-welded. Weld or resistance weld. According to such a manufacturing method, compared with the conventional example shown in FIGS. 7 (A) and 7 (B), the welding strength can be improved while significantly reducing the working time.

However, in the conventional example shown in FIGS. 8A and 8B, the entire surface of the cathode substrate 2 is in contact with the surface of the second electrode 14, and the cleanliness of the surface of the second electrode 14 and Smoothness is required. The surface of the second electrode 14 has been sufficiently washed and smoothed, but when viewed microscopically, it has some irregularities and dirt. Further, it is difficult to sufficiently smooth the surface of the cathode substrate 2 and it is difficult to bring the cathode substrate 2 and the second electrode 14 into a perfect surface contact state.

If resistance welding is performed in this state, a large amount of welding current partially flows, and there is a problem that the electron emitting substance contained in the cathode substrate 2 seeps out and is contaminated by other substances. When the electron emitting substance seeps out to the surface of the cathode substrate 2, the electron emitting substance contained in the cathode substrate 2 is evaporated by heat during the operation of the cathode ray tube and adheres to the grid holes, so that the electron emission should not be originally performed. Electrons may be emitted from the grid holes. If the electron emission is generated from the portion where the electron emission should not be originally generated, a surface stray phenomenon (a phenomenon in which the periphery of the cathode ray tube is blurred when the panel is illuminated) is not preferable.

Further, if the electron emitting material exuded from the surface of the cathode 2 adheres to the sleeve 6 or the like, there is a problem such as leakage during operation of the cathode ray tube. Further, in the conventional method shown in FIG. 8, carbon or the material forming the second electrode 14 may adhere to the surface of the cathode substrate 2 from the surface of the second electrode 14, and the contamination thereof becomes a problem. Particularly, when carbon adheres to the surface of the cathode substrate, the characteristics as a cathode deteriorate.

The present invention has been made in view of the above circumstances, and effectively suppresses the exudation and contamination of the electron-emitting material on the surface of the cathode substrate, particularly at the electron-emitting portion, so that the electrons from other than the cathode substrate are effectively suppressed. A method of manufacturing a cathode structure of a cathode ray tube, which can prevent radiation and prevent leakage between cathode electrodes and can mass-produce a cathode structure having excellent electron emission characteristics in a short time with good workability, and to use it The purpose is to provide a device.

[0012]

In order to achieve the above object, a method of manufacturing a cathode assembly of a cathode ray tube according to the present invention comprises a step of impregnating or applying an electron emitting substance on at least a surface side of a cathode substrate, and a cathode. The cup body is attached so as to cover the back surface side of the base body, and the cup body and the cathode base body are
A method of manufacturing a cathode assembly of a cathode ray tube, comprising the step of resistance welding between a first electrode and a second electrode, wherein the second electrode has a first hole and a substantially concentric portion below the first hole. A second hole that is positioned in a circular shape and is smaller than the inner diameter of the first hole, and the cup body having the cathode base mounted therein is housed in the first hole with the surface of the cathode base facing downward. The resistance welding between the cup body and the cathode substrate is performed by pressing the first electrode against the cup body and causing a current to flow between the first electrode and the second electrode.

In the apparatus for manufacturing a cathode assembly of a cathode ray tube according to the present invention, a cup body is mounted so as to cover at least the back surface side of a cathode substrate impregnated or coated with an electron emitting substance on the front surface side. 1. A manufacturing apparatus for a cathode assembly of a cathode ray tube, wherein a base body and a first electrode and a second electrode are resistance-welded to each other, wherein the second electrode is a cup body having the cathode base body mounted thereon. Hole that enters so that its surface faces downward, and a second hole that is located substantially concentrically below the first hole and that is smaller than the inner diameter of the first hole.
Holes are formed.

The inner diameter of the second hole formed in the second electrode is preferably set larger than the outer diameter of the working area on the surface of the cathode substrate. The inner diameter of the second hole formed in the second electrode is preferably set to be 0.2 mm or more smaller than the outer diameter of the cathode substrate.

The second electrode is preferably constructed by laminating an insulating plate member having the first hole and a conductive plate member having the second hole.

[0016]

When the cathode assembly is manufactured using the manufacturing apparatus according to the present invention, the working area corresponding to the electron emitting portion on the surface of the cathode substrate is located within the area of the second hole formed in the second electrode. Therefore, it does not come into contact with the second electrode. Therefore, a current for resistance welding does not flow in that portion, and the electron emitting material does not seep out in the working area. Moreover, the working area is not contaminated by the contaminants from the second electrode.

The current for resistance welding flows to the second electrode through the periphery of the working area on the surface of the first electrode, the cup body, the cathode base body and the cathode base body, and the cup body and the cathode base body are well resistance welded. And its welding strength is also sufficient. Since the emission of the electron emitting substance is eliminated in the working area of the cathode substrate, the electron emitting substance does not adhere to the portion other than the cathode substrate due to the evaporation of the electron emitting substance, and the electron emission from the portion other than the cathode substrate is considerably reduced. Further, for the same reason, the leakage between the cathode electrodes also decreases. In particular, when the electron emitting substance adheres to the electron beam passage holes (grid holes) of the first grid, the cut-off voltage changes due to the change of the electric field of the grid, which causes a problem that the white balance is lost. It disappears.

Further, since the working area on the surface of the cathode substrate is not contaminated, the deterioration of electron emission characteristics due to the contamination is also eliminated. The leaching of the electron emitting material and the contamination with other materials are considerably reduced even in a portion other than the working area on the surface of the cathode substrate.

In the resistance welding of the method according to the present invention, sufficient welding strength can be obtained by welding several points on the bottom of the cup body, so that the working time can be greatly reduced and the mass productivity is excellent. There is.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a cathode assembly of a cathode ray tube according to the present invention and an apparatus used therefor will be described in detail below with reference to the embodiments shown in the drawings. First, the overall structure of a cathode ray tube (CRT) and a cathode assembly used for it will be described.

As shown in FIG. 5, the CRT 20 has a panel glass 22 and a funnel glass 24, which are fused by a frit glass 26 and the inside is maintained in a high vacuum. On the neck 28 of the funnel glass 24,
The electron gun 30 is built in. A fluorescent screen 32 is formed on the inner surface of the panel glass 22, and an aperture grill 34 is attached to the rear surface thereof. Further, a deflection yoke 36 is attached to the outer periphery of the neck portion 28, and the three electron beams emitted, controlled, accelerated, and focused from the electron gun 30 are deflected by the deflection yoke 36, thereby causing fluorescence. Surface 3
The entire surface of 2 is scanned.

The electron gun 30 is composed of, for example, a cathode structure (cathode) 40 shown in FIG. 6 and a grid group (only the first grid 42 is shown in FIG. 4). The cathode assembly 40 of this embodiment is composed of three sleeves 44R, 4 with cathode substrates.
It has 4G and 44B. Each sleeve 44R, 44G, 4
4B has a cathode base (BM) having an electron emitting substance at its tip which generates thermoelectrons when heated.
46 is attached. Sleeve 44 with each cathode substrate
R, 44G, and 44B are manufactured by welding and fixing the cathode substrate 46 to the tip of the sleeve body 45 by a method described later.

Sleeves 44R and 44 with cathode substrates
The G and 44B are arranged so as to be inserted through the three openings 50 formed in the insulating disk 48, respectively. The insulating disc 48 is made of, for example, a ceramic disc. For example, forsterite, steatite, alumina or the like can be used as the ceramic.

One end of a pair of V tabs 52, 54 formed by bending a thin metal wire into a V shape is welded to the outer periphery of the rear ends of the sleeves 44R, 44G, 44B, respectively. The other ends of the V tabs 52 and 54 are connected to the three pairs of metal pins 56 and 58 fixed to the back surface of the insulating disk 48 by welding or the like. The metal pins 56 and 58 are fused and fixed to the insulating disk 48 with glass or the like. Red (R), green (G), and blue (B) signals are input from the three pairs of metal pins 56 and 58, respectively.

On the back surface of the insulating disk 48, in addition to the metal pins 56, 58, four heater rest fixing metal pins 62 for fixing the pair of heater rests 60, 60.
However, they are fused and fixed by the same means as the metal pins 56 and 58. For these metal pins 62, the heater rest 6
By welding 0 and 60, the heater rest 60,
60 is fixed to the insulating disk 48. The heater rests 60, 60 include sleeves 44R, 44G,
The power supply terminals of the heater 64 (see FIG. 4) mounted inside 44B are connected to each other. That is, by applying a predetermined voltage to the heater rests 60, 60, the heaters 64 mounted inside the sleeves 44R, 44G, 44B are heated.

Next, the sleeve with the cathode substrate will be described. In the case of a color cathode ray tube, three sleeves with cathode substrates are prepared for R, G, and B for one electron gun. Since the sleeves with a cathode substrate have the same structure, only one sleeve 44 with a cathode substrate will be described below.

As shown in FIG. 4, the sleeve 44 with a cathode substrate has a sleeve body 45 and a cathode substrate 46 welded to the tip of the sleeve body 45 via a cup body 66.
The cathode substrate 46 is made of, for example, a porous sintered body made of a refractory metal such as tungsten (W), and the porous sintered body is made of an electron emitting material made of Ba, Ca, Al or the like. It is melt impregnated.

The sleeve body 45 has, for example, a diameter of 1 to 2.
mm, thickness 10 to 30 μm, length 6 to 7 mm and made of a refractory metal cylinder such as Ni or Ni—Cr.
The cup body 66 is made of a refractory metal such as W or Ni. On the bottom surface of the cathode base 46 (the side covered with the cup body 66), a brazing material or a metal film 68 for strengthening the welded joint between the cathode base 46 and the cup body 66.
Is deposited. As the metal film 68, iridium (I
A thin film of r), ruthenium (Ru), molybdenum (Mo), or an alloy thereof can be used. The thickness of these thin films is not particularly limited, but may be, for example, 1
It is about 100 to 1000 nm.

A work function lowering film 70 for lowering the work function and realizing electron emission at a lower temperature is preferably formed on the surface of the cathode substrate 46. For the work function lowering film 70, it is preferable to use a platinum-based metal such as Ir. As described above, the heater 64 is built in the sleeve body 45. Heater 64
Is a heating wire such as a pure tungsten wire or a tungsten alloy wire in which tungsten is doped with 2 to 3% of rhenium (Re).

On the front side of the sleeve with cathode substrate 44, a grid group forming a part of the electron gun 30 shown in FIG. 5 is arranged. In FIG. 4, only a part of the first grid 42 is shown. Next, a method for welding and joining the cathode base 46 and the cup body 66, which is a main part of the method for manufacturing the cathode assembly of the cathode ray tube according to the embodiment of the present invention, and an apparatus used therefor will be described.

In the method of this embodiment, first, Ba and C are added to the cathode substrate 46 composed of the porous sintered body shown in FIG.
An electron emitting material composed of a, Al, etc. is melt-impregnated. The conditions for the melt impregnation are not particularly limited, but the electron emitting substance is melted at a temperature of, for example, 1800 ° C., and the cathode substrate 46 is immersed therein for about 3 minutes.

Next, a brazing material or a metal film 68 is formed on the back surface of the cathode substrate 46. As described above, the brazing material or the metal film 68 is formed in order to strengthen the welded joint between the cathode substrate 46 and the cup body 66.
The film thickness is not particularly limited, but is 1000 to 1000.
It is 0 angstrom.

Next, a cup body 66 is attached so as to cover the back surface side of the cathode substrate 46, and the cup body 66 is attached to the second body shown in FIG.
The cathode substrate 46 is fitted into the first hole 76 formed in the electrode 74 so that the surface of the cathode substrate 46 faces downward. Second electrode 7
A second hole 78, which is located substantially concentrically below the first hole 76 and is smaller than the inner diameter of the first hole 76, is formed in the No. 4.

As shown in FIG. 2, a large number of first holes 7 are formed in the second electrode 74 at an appropriate pitch from the viewpoint of mass productivity.
6 and a second hole 78 substantially concentric therewith are preferably formed. An appropriate pitch, which is the distance between the centers of the first holes 76, is determined from the viewpoint of workability of the first electrode 72 shown in FIG. 1 and is not particularly limited, but is, for example, about 5 mm.

As shown in FIG. 3, a first hole 76 and a second hole 78 are formed in the second electrode 74, and flatness of the stepped portion 80 is required. This is because the surface of the cathode substrate 46 contacts the surface of the stepped portion 80 as shown in FIG. Therefore, as shown in FIG. 3, the second electrode 74 includes a first plate member 82 having a first hole 76 and a second plate member 82.
It is preferable that the second plate member 84 in which the hole 78 is formed is laminated and formed. This is because flatness processing of the step portion 80 becomes easy. The concentricity of the first hole 76 and the second hole 78 does not necessarily have to be strict, and the concentricity is determined so that at least one side area s of the step portion 80 is at least 0.1 mm or more. It

In addition, resistance from the first electrode 72 shown in FIG. The first plate member 82 shown in FIG. 3 is preferably an insulating plate member (for example, a ceramic member) so that the welding current flows conveniently. As a matter of course, the second plate member 84 is made of a conductive plate member made of a refractory metal or the like. The first plate member 82 shown in FIG. 3 preferably has an insulating property in order to reduce damage to the cup body 66 due to electric discharge during resistance welding.

The inner diameter Da of the first hole 76 shown in FIG.
The outer diameter of the cup body 66 shown in FIG.
03-0.1 mm, more preferably 0.05-0.08
It is preferably about mm. The depth ta of the first hole 76 is substantially equal to the axial length of the cup body 66 with a cathode substrate shown in FIG. It is set to a depth. Preferably, the first hole 7
The depth ta of 6 is such that the bottom surface of the cup body 66 shown in FIG.
It is set to a depth of about 0.1 mm protruding from the hole 76. This is because the cup body 66 can be easily taken out after welding. Specifically, the depth ta of the first hole 76
Is set to about 0.7 mm. The total thickness T of the second electrode 74 is not particularly limited, but is the depth t of the first hole 76.
It is set to about twice as large as a. Specifically, about 1.
It is about 5 mm.

The inner diameter Db of the second hole 78 is set to be larger than the working area (electron emitting portion) 86 located at the center of the surface of the cathode substrate 46 shown in FIG. The working area 86 is defined by a value obtained by multiplying the inner diameter region of the grid hole (electron beam passage hole) 88 of the first grid 42 by the drive rate, and the inner diameter of the grid hole 88 is 0.3.
.About.0.7 mm, the area 86 has a diameter of 0.1.about.0.
It is an area of 7 mm.

Further, as shown in FIG. 3, since the area of the stepped portion 80 needs to be about 0.1 mm or more in the one side area s,
Generally, the inner diameter Db of the second hole 78 is preferably about 0.7 to 0.9 mm, though it depends on the type of CRT. In this case, the outer diameter of the cathode substrate 46 is about 1.15 mm.

As shown in FIG. 1, after the cup body 66 having the cathode substrate 46 mounted therein is fitted into the first hole 76 of the second electrode 74 so that the surface of the cathode substrate 46 faces downward, , The first electrode 72 is brought into contact with the bottom surface of the cup body 66, and the portion is pressed at about 1 to ² Kg / cm ² , and the resistance is provided between the first electrode 72 and the second electrode 74 as shown by an arrow Ia. Apply welding current. The wattage at the time of resistance welding is not particularly limited, but is, for example, 10 to 20 watts.
During resistance welding, in order to prevent oxidation of the cup body 66, it is preferable to blow an inert gas such as Ar onto the cup body 66.

The contact of the first electrode 72 with the bottom surface of the cup body 66 may be a few points. Since a large number of first holes 76 are formed in the second electrode 74 as shown in FIG. 2, a large number of cup bodies 66 with a cathode substrate are accommodated in the first holes 76 at the same time, and the resistance welding is performed sequentially. By doing so, mass productivity can be improved. Further, the first electrodes 72 may be provided in correspondence with the number and pitch of the first holes 76, and a large number of cup bodies 66 with cathode substrates may be resistance-welded at the same time.

If resistance welding is performed using the first electrode 72 and the second electrode 74 according to this embodiment, a working area 86 corresponding to an electron emitting portion on the surface of the cathode substrate 46.
Is located in the area of the second hole 78 formed in the second electrode 74, and therefore does not contact the second electrode 74.
Therefore, the electric current for resistance welding does not flow in that portion, and the electron emitting material does not seep out in the working area 86. Also, working area 8
6 will not be contaminated by contaminants from the second electrode 74.

The current for resistance welding passes through the first electrode 72, the cup body 66, the brazing material or the metal film 68, the cathode base 46, and the periphery of the working area 86 on the surface of the cathode base 46, as shown by the arrow Ia. , The second electrode 74, and the cup body 66 and the cathode substrate 46,
It is well resistance welded and its welding strength is sufficient.

Thereafter, as shown in FIG. 4, the cup body 46 with the cathode substrate is fitted (caulked as necessary) to the upper end portion of the sleeve body 45, and resistance welding or laser is performed from around the upper end of the sleeve body 45. Weld. Before and after that, the work function lowering film 70 shown in FIG. 4 is formed on the surface of the cathode substrate 46.

Thereafter, as shown in FIG. 4, a heater 64 is arranged inside the sleeve main body 45, and the sleeve 44 with the cathode substrate is shown in FIG. 6 (in FIG. 6, the sleeves 44R, 44G, 44B with the cathode substrate). As shown in FIG. 5, the cathode assembly 40 is manufactured by attaching it to the insulating disk 48, attaching the heater rest 60, the metal pins 56 and 58, and the like.

In this embodiment, the cathode substrate 4 shown in FIG.
Since the emission of the electron emitting material is eliminated in the working area 86 of 6, the electron emitting material is not attached to the portion other than the cathode substrate 46 due to the evaporation of the electron emitting substance, and the electron emission from the portion other than the cathode substrate 46 is considerably small. Become. Further, for the same reason, the leakage between the cathode electrodes also decreases. In particular, when an electron emitting substance adheres to the electron beam passage hole (grid hole 88) of the first grid 42, the cut-off voltage changes due to a change in the electric field of the grid, which causes a problem that the white balance is lost. In the embodiment it is eliminated.

Further, since the working area 86 on the surface of the cathode substrate 46 is not contaminated, the deterioration of electron emission characteristics due to the contamination is also eliminated. The exudation of the electron-emitting substance and the contamination with other substances are caused by the cathode substrate 46.
It will be much less in areas other than the working area on the surface.

In the resistance welding of the method according to this embodiment, a sufficient joining strength can be obtained by welding several points on the bottom of the cup body 66, so that the working time can be greatly shortened and the mass productivity can be improved. Are better. The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways within the scope of the present invention.

For example, in the above embodiment, a color CRT is used.
Although the cathode structure for a CRT has been described, the present invention can be similarly applied to a cathode structure for a black and white CRT. In that case, the single sleeve 44 with the cathode substrate may be arranged on the insulating disk.

In the method of the above embodiment, the cup body 66 is resistance-welded to the cathode substrate 46, and then the cup body 66 is formed.
Is configured to be resistance-welded or laser-welded to the sleeve body 45. In the present invention, after the sleeve body 45 is welded to the cup body 66, the cathode substrate 46 is resistance-welded to the cup body 66 by the above method. Is also good.

[0051]

As described above, according to the present invention, the electron emitting material does not exude on the surface of the base metal, especially in the working area. Moreover, the working area is not contaminated by the contaminants from the second electrode. The leaching of the electron emitting material and the contamination with other materials are considerably reduced even in a portion other than the working area on the surface of the cathode substrate. For example, when observing the entire surface of the cathode substrate, it has been confirmed that the exudation of the electron emitting substance and the contamination with other substances were 50% in the conventional case, but can be about 3% in the present invention. Was done. Further, it has been confirmed that in the working area on the surface of the cathode substrate, the exudation of the electron emitting substance and the contamination with other substances were 30% in the related art, but can be 0% in the present invention.

The current for resistance welding flows to the second electrode through the periphery of the working area on the surface of the first electrode, the cup body, the cathode substrate, and the cathode substrate, and the cup body and the cathode substrate are well resistance welded. And its welding strength is also sufficient. Since the emission of the electron emitting substance is eliminated in the working area of the cathode substrate, the electron emitting substance does not adhere to the portion other than the cathode substrate due to the evaporation of the electron emitting substance, and the electron emission from the portion other than the cathode substrate is considerably reduced. Further, for the same reason, the leakage between the cathode electrodes also decreases. In particular, when the electron emitting substance adheres to the electron beam passage holes (grid holes) of the first grid, the cut-off voltage changes due to the change of the electric field of the grid, which causes a problem that the white balance is lost. It disappears. Further, for the same reason, the surface stray phenomenon can be reduced.

Further, since the working area on the surface of the cathode substrate is not contaminated, the deterioration of electron emission characteristics due to the contamination is also eliminated. In the resistance welding of the method according to the present invention, a sufficient joining strength can be obtained by welding several points on the bottom of the cup body, so that the working time can be greatly shortened and the mass productivity is excellent.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a resistance welding method for manufacturing a cathode assembly according to an embodiment of the present invention.

FIG. 2 is a plan view of a second electrode used in the embodiment shown in FIG.

FIG. 3 is a cross-sectional view of essential parts of a first hole and a second hole formed in the second electrode shown in FIGS.

FIG. 4 is a schematic cross-sectional view showing the positional relationship between the cathode base and the first grid after resistance welding.

FIG. 5 is a schematic view of a cathode ray tube.

6 (A) is a schematic half sectional view of the cathode assembly, and FIG. 6 (B) is a bottom view taken along line BB shown in FIG. 6 (A).

7 (A) and 7 (B) are respectively a plan view and a side sectional view showing a resistance welding method for a cathode substrate according to a conventional example.

8A and 8B are a first step diagram and a second step diagram, respectively, showing a resistance welding method for a cathode substrate according to a conventional example.
It is a process drawing.

[Explanation of symbols]

 40 ... Cathode structure 42 ... First grid 44 ... Cathode substrate sleeve 45 ... Sleeve body 64 ... Heater 66 ... Cup body 68 ... Metal film 70 ... Work function lowering film 72 ... First electrode 74 ... Second electrode 76 ... First Hole 78 ... Second hole 80 ... Step 82 ... First plate material (insulating plate material) 84 ... Second plate material (conductive plate material)

Claims (8)

[Claims] 1. A step of impregnating or applying an electron emitting substance onto at least the front surface side of a cathode substrate, and a cup body is attached so as to cover the back surface side of the cathode substrate, and the cup body and the cathode substrate are connected to the first electrode. A method of manufacturing a cathode assembly of a cathode ray tube, comprising the step of resistance welding between the first electrode and a second electrode, wherein a first hole and a substantially concentric position below the first hole are formed in the second electrode. And forming a second hole smaller than the inner diameter of the first hole, and accommodating the cup body, on which the cathode substrate is mounted, in the first hole so that the surface of the cathode substrate faces downward,
A method for manufacturing a cathode assembly of a cathode ray tube in which the first electrode is pressed against the cup body, and a current is passed between the first electrode and the second electrode to perform resistance welding between the cup body and the cathode substrate. . 2. The manufacturing method of a cathode assembly of a cathode ray tube according to claim 1, wherein the inner diameter of the second hole formed in the second electrode is set larger than the outer diameter of the working area on the surface of the cathode substrate. Method. 3. The cathode assembly of the cathode ray tube according to claim 1, wherein the inner diameter of the second hole formed in the second electrode is set to be 0.2 mm or more smaller than the outer diameter of the cathode substrate. Manufacturing method. 4. The second electrode is formed by laminating an insulating plate member having the first hole and a conductive plate member having the second hole. A method for manufacturing a cathode structure of a cathode ray tube according to any one of claims. 5. A cathode substrate, at least the surface side of which is impregnated or coated with an electron emitting substance, is covered so as to cover the back side thereof.
The cup body is attached, and the cup body and the cathode base are
A device for manufacturing a cathode assembly of a cathode ray tube, wherein resistance welding is performed between an electrode and a second electrode, wherein a cup body having the cathode base mounted on the second electrode has a surface of the cathode base facing downward. An apparatus for manufacturing a cathode assembly of a cathode ray tube, comprising: a first hole that is inserted into the first hole; and a second hole that is located substantially concentrically below the first hole and that is smaller than the inner diameter of the first hole. 6. The manufacturing method of a cathode assembly for a cathode ray tube according to claim 5, wherein the inner diameter of the second hole formed in the second electrode is set larger than the outer diameter of the working area on the surface of the cathode substrate. apparatus. 7. The cathode assembly of a cathode ray tube according to claim 5, wherein an inner diameter of the second hole formed in the second electrode is set to be 0.2 mm or more smaller than an outer diameter of the cathode substrate. Manufacturing equipment. 8. The second electrode is formed by laminating an insulating plate material having the first hole and a conductive plate material having the second hole. An apparatus for manufacturing a cathode structure of a cathode ray tube according to any one of claims.