JP2001093435A - Cathode-ray tube and electron gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize higher precision in a cathode-ray tube. SOLUTION: Cathode sleeves 31 of cathode bodies KR, KG, and KB are formed of ceramic materials, wherein the cathode bodies organize an electron gun used for a cathode-ray tube. The cathode bodies KR, KG, and KB are arranged on a ceramic board 37 which is formed in one body with spacers 39A and 39B so as to organize a structural body of a cathode 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cathode ray tube and an electron gun used for the same.

[0002]

2. Description of the Related Art Conventionally, a high definition cathode ray tube has required an electron gun capable of narrowing an electron beam more finely.

[0003] Figure 13 shows an example of the configuration of the first grid G ₁ and the cathode vicinity in a conventional electron gun. The cathode, that is, the cathode body 1 is provided with an electron emission portion 5 made of, for example, an alkaline earth metal oxide via a cap 4 serving as a cathode base at an upper end of a cylindrical cathode sleeve 3 having a heater 2 built therein. Sleeve 3
And a cathode sleeve support member 7 is joined thereto.

The cathode body 1 is attached to a support substrate 8 made of, for example, ceramic by welding a glass material 9 through a cathode sleeve support 7. The cathode body 1 and the support substrate 8 constitute a so-called cathode structure 10.

The lower portion of the cathode sleeve 3 is integrated with the lower portion of the cathode sleeve support 7 by laser welding. a shows a welding part. Cathode structure 10, the first grid G ₁ constituting the electron gun is inserted through the spacer 11, the retainer 1 is further inserted retainer 12 is
2 and the first grid G ₁ are fixed in the first grid G ₁ by laser welding.

For the cathode sleeve 3, metals such as nickel, Kovar (Fe-Ni-Co metal), tantalum, and other metals have been used from the viewpoint of ease of processing and welding, good heat conduction, and the like. Kovar or the like is used for the cathode sleeve support 7.

[0007]

By the way, higher definition
The first grid G₁Electron beam transmission of
The hole diameter r of the hole 14 is further reduced, and the cathode
Body 1 and first grid G ₁Distance d between₀₁Further shrink
There is a need.

However, a nickel-based cathode sleeve
3, the coefficient of thermal expansion is large and the distance d ₀₁Limit to shrink
Even with low thermal expansion coefficient tantalum, cathode sleeve 3
Although it depends on the supporting method of the cathode ray tube,
When the sword main body 1 is heated, it finally expands by about 40 μm or more.
And variations due to welding distortion, etc.
growing.

The heater 2 is coated with alumina for insulation between the winding portion and the cathode sleeve 3, but the coating between the cathode sleeve 3 and the heater 2 is caused by peeling of the coating film or generation of cracks. Leakage current due to contact may flow, causing a problem.

[0010] The present invention has been made in view of the above points, the pore size of the cathode and the distance d ₀₁ and the first grid of the electron beam transmitting hole between the first grid and smaller, allowing a higher resolution of the cathode ray tube And its electron gun.

[0011]

According to the present invention, a cathode sleeve of a cathode body constituting an electron gun is formed of a ceramic material.

In the present invention, by forming a cathode sleeve with a ceramic material, the thermal expansion of the cathode sleeve is suppressed, the cathode and the distance d between the first grid G _1
01 can be reduced. This allows to narrow thin electron beam the pore size of the first grid G ₁ of the electron beam transmitting hole and smaller.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cathode ray tube according to the present invention comprises an electron gun in which a cathode sleeve of a cathode main body is formed of a ceramic material.

According to the present invention, in the above-mentioned cathode ray tube, the cathode sleeve of the electron gun is vertically arranged such that the axis of the cathode sleeve is perpendicular to the plate surface of the support substrate, and is provided at the upper end of the cathode sleeve in the axial direction. It is configured to have an electron emission portion.

According to the present invention, in the above-mentioned cathode ray tube, the cathode sleeve of the electron gun is arranged horizontally so that the axis of the cathode sleeve is along the plate surface of the support substrate, and is disposed on the upper surface in a direction orthogonal to the axis of the cathode sleeve. It is configured to have an electron emission portion.

In the electron gun according to the present invention, the cathode sleeve of the cathode main body is formed of a ceramic material.

According to the present invention, in the above-mentioned electron gun, the cathode sleeve is vertically arranged such that the axis of the cathode sleeve is perpendicular to the plate surface of the support substrate, and the electron emission portion is provided at the upper end in the axial direction of the cathode sleeve. Is provided.

According to the present invention, in the above-mentioned electron gun, the cathode sleeve is arranged horizontally so that the axis of the cathode sleeve is along the plate surface of the support substrate, and the electron emission portion is provided on the upper surface in a direction orthogonal to the axis of the cathode sleeve. Is provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 4 show an embodiment in which the cathode ray tube according to the present invention is applied to a color cathode ray tube. As shown in FIG. 1, a color cathode ray tube 21 according to the present embodiment includes red (R), green (G), and blue (B) in a neck portion 23 of a cathode ray tube (glass tube) 22. An electron gun 24 for emitting three corresponding electron beams is enclosed and arranged, and a deflection yoke 25 is formed outside the tube 22. Although not shown, a color phosphor screen composed of red, green, and blue phosphor stripes is formed on the inner surface of the panel, and a color selection mechanism is arranged to face the color phosphor screen.

The electron gun 24 has three cathodes corresponding to red (R), green (G) and blue (B), that is, a cathode body K.
[K _R, K _G and K _B] and the supporting substrate 3 for supporting the
Has a cathode structure 28 according to the present invention described below consisting of 7 for three cathode body K _R, K _G, the first grid G ₁ of each common to K _B, the second grid G _2, the third grid G ₃ , a fourth grid G _4, and a fifth grid G ₅ are arranged coaxially, and are composed of _four electrostatic deflection electrode plates C ₁ , C ₂ , C _3, and C ₄ at the subsequent stage of the fifth grid G _5. Electrostatic convergence means C is arranged.

[0022] The third grid G _3, and the fifth grid G ₅ anode voltage is applied, the fourth grid G ₄ are applied focusing voltage, the third grid G _3, fourth grid G ₄ and the fifth the main electron lens L by a grid G ₅
m is configured. An anode voltage is applied to the electrostatic deflection electrode plates C ₂ and C ₃ inside the electrostatic convergence means C, and a high voltage slightly lower than the anode voltage is applied to the outside electrostatic deflection electrode plates C ₁ and C _4. You.

[0023] In the electron gun 24, after the three cathode body _{K R, K G, K B} 3 one electron beam B _r emitted from, B _g, B _b crosses the main electron lens Lm, electrostatic convergence Converged on the phosphor screen through means C.

In this embodiment, in particular,
The cathode structure 28 constituting the electron gun 24 of FIG. 1 is configured as shown in FIGS. 2 to 4, for example. FIG. 2 shows a cathode structure 281 according to one embodiment. In the present embodiment, the cathode sleeve 31 is formed of a ceramic material having a small coefficient of thermal expansion such as, for example, alumina or silicon carbide (SiC). When the main component is alumina, the one containing about 90% of alumina can be used. Further, aluminum nitride having a smaller coefficient of thermal expansion and better thermal conductivity than alumina can be used. The cathode sleeve 31 is formed, for example, in a cylindrical shape such as a cylindrical shape or a square shape, in this example, a cylindrical shape. A ring-shaped metal plate 32 made of, for example, Kovar is provided on a distal end surface of the cylindrical ceramic cathode sleeve (hereinafter, referred to as a ceramic sleeve) 31.
The cathode body K [K _R , K _G , K _B ] is configured by mounting an electron emission portion 34 via a cathode cap 33 and incorporating a heater 35 in the ceramic sleeve 31.

On the other hand, three cathode body K _R, insulating support substrate for supporting the K _G and K _B, the ceramic substrate 37 is provided, for example. Ceramic substrate 37, three cathode body K _R, K three insertion holes 38 [38R, 38G and 38B] to insert the _G and K _B together is formed, the ceramic substrate 3 in both sides of the three insertion holes 38
7 and a pair of ceramic spacers 39A and 39B
Is formed. The spacers 39A and 39B have, for example, a rectangular column shape, and can be formed integrally with the ceramic substrate 37. Kovar pins 41A and 41B for fixing the pair of heater rests 40A and 40B are erected on the ceramic substrate 37.

The insertion hole 38 of the ceramic substrate 37
R, to 38G and 38B, and inserted respectively corresponding three cathode body K _R, K _G and K _B, brazed through a brazing material 43, the three cathode body K _R, K _G and K _B
Structure 28 which integrates a ceramic substrate 37 with the cathode structure 28
1 is configured.

The cathode assembly 281 has a structure in which the cathode sleeve 31 is arranged in a so-called vertical shape such that the axis m is perpendicular to the plate surface of the ceramic substrate 37.

The insertion hole 38 of the ceramic substrate 37 [38
R, 38G, 38B], as shown in FIG. 5, in plan view, the cathode body K [K _R, K _G, the insertion portion 3 of the K _B]
8a and a space 38b communicating therewith. With the insertion hole 38 having such a shape, the contact area between the cathode sleeve 31 and the ceramic substrate 37 is reduced, the escape of the heat of the heater 35 during operation is reduced, and the gas is passed through the space 38b during the heat treatment in a later step. Be able to pull out.

The cathode structure 281 is manufactured, for example, as follows. Cylindrical ceramic sleeve 31
And a ring-shaped metal plate, for example, a Kovar material 32, is brazed to the tip end surface of the ceramic sleeve 31 via a brazing material 39 made of a high-temperature active metal. On the other hand, a ceramic substrate 37 is provided, and each of the insertion holes 38 [38R, 38] is provided.
G, 38B], and the ceramic sleeve 31 is brazed to the ceramic substrate 37 via the brazing material 43 attached in advance.

[0030] Two spacers 39A and 39B integrally on the ceramic substrate 37, as shown in FIG. 6A, after the size out of the height h ₁ and polishing the upper surface, the sheet metal on the upper surface thereof, for example The Kovar sheet 44 is brazed. The ceramic substrate 37 has a heater rest 40.
Kovar pins 41A and 41B for fixing A and 40B are fixed with, for example, a glass material.

At the time of brazing, a heat-resistant active metal (brazing material) 3 is applied only to the end face of the ceramic sleeve 31.
In step 9, the ring-shaped Kovar plate 32 is brazed in advance. As the brazing material, a heat-resistant active metal having a temperature of about 400 ° C. or more can be used. For example, a gold brazing material brazed at about 960 ° C. can be used. Next, the brazing between the remaining cathode sleeve 31 and the ceramic substrate 37 and the brazing of the Kovar thin plate 44 on the columnar spacers 39A and 39B, that is, the softening temperature will be lower than the brazing material of the ring-shaped Kovar plate 32 at the upper end of the sleeve. Brazing with materials is performed at the same time. As the brazing material at this time, a brazing material that can be brazed at a lower temperature, for example, about 300 ° C. than the above-mentioned heat-resistant active metal is used.

After completion of the brazing step, as shown in FIG. 6B, a square columnar spacer 39 on the ceramic substrate 37 is formed.
Polishing the upper surface of the Kovar sheet 44 which is brazed to the A and 39B perform height h ₂ of the dimension out, the spacer upper surface as a reference, the polishing surface of the ring-shaped Kovar plate 32 of the tip of the ceramic sleeve 31 The surface of the ring-shaped Kovar plate 32 at the end of the sleeve 31 and the spacers 39A, 39
Adjusting the distance between the surface of the Kovar sheet 44 on the B to a predetermined distance d _01.

Next, a cathode cap 33 incorporating a so-called electron emission portion 34 such as an impregnated cathode member or an oxide cathode member is welded to the ring-shaped Kovar plate 32 at the tip of the ceramic sleeve 31. This example is a case where an impregnated cathode member is used as the electron emission section 34. At this time, as shown in FIGS. 7A and 7B, the cathode 46 is welded to the extension 32a of the ring-shaped Kovar plate 32. Spacers 39A at the time of welding the cathode cap 33, 39B and the first grid G ₁ and the cathode body K of intervals (the so-called below the surface of the electron emission portion 34
As a final adjustment of [K _R, K _G, K _B] corresponds to the distance d ₀₁ between), spacers 39A, 39B and the first grid G
It is also possible to insert a thin plate of Kovar or the like between the welding surfaces with the _one to make adjustment. Heater rest 40A and 40B
Are connected to the ceramic sleeves 31, and the heater rests 40A and 40B are electrically and mechanically fixed to the Kovar pins 41A and 41B of the ceramic substrate 37. The heater 35 is coated with, for example, an alumina film for insulation. Thus, the cathode structure 281 is manufactured.

The cathode structure 281 is similar to the structure shown in FIGS.
As shown in the upper surface of the spacer 39A and 39B, i.e., the surface of the Kovar sheet 44 is disposed in the first grid G ₁ to abut the upper surface of the first grid G _1, the first grid G ₁ and the spacer upper surface Kovar sheet 44 is welded, and the first grid G ₁ and the cathode structure 28 are joined. Further, the ceramic substrate 37 of the cathode structure 281
The retainer 47 for fixing the lower surface is welded to the first grid G _1, the cathode structure 281 and the first assembly of the grid G ₁ is completed.

First grid G ₁ and cathode body K
It is quite possible to obtain a distance of about 30 μm as the distance d ₀₁ between [K _R , K _G , K _B ], taking into account the accuracy of brazing and the dimensional accuracy due to polishing of the ceramic material.

FIGS. 8A and 8B show a cathode body K in the case where an oxide cathode member is used as the electron-emitting portion 34. FIG.
[K _R, K _G, K _B] is an example of.

According to the present embodiment, the color cathode ray tube 2
As an electron gun 24, in particular its cathode structure 28, cathode body K _R, K _G, K cathode structure 28 the cathode sleeve 31 is formed of a ceramic material of low thermal expansion coefficient _B
By setting it to 1, the elongation of the cathode sleeve due to thermal expansion can be suppressed to about half of that of a metal sleeve made of nickel or the like. In the ceramic sleeve 31, the change in dimension in the cathode ray tube manufacturing process due to distortion at the time of welding or the like is considerably smaller than that of a nickel-based or tantalum cathode sleeve. Therefore, I can coupled with the elongation due to thermal expansion of the cathode sleeve 31 is kept small, the first grid G ₁ and the cathode body K _R, K _G, to be smaller than the conventional distance d ₀₁ between the K _B Can be.

By reducing the distance d ₀₁ ,
It is possible to further reduce the pore size r of the first electron beam transmitting hole 48 of the grid G _1, it is possible to narrow finer electron beam. Therefore, a higher definition cathode ray tube can be manufactured.

The cathode structure 281 is provided in the first grid G ₁ .
Is not required to provide a separate spacer as in the prior art, so that the assembly accuracy at the time of welding, including the retainer 47, is relatively stable. While the heater 35 is coated, for example, alumina insulating coating, by using a high electrical insulating precision ceramic sleeve 31, a heater 35 and cathode body K [K _R, K _G, K _B]
No leak current flows due to contact with the substrate. As a result, the coating thickness of alumina can be reduced, and the heating efficiency of the electron-emitting portion 34 is increased, and the power consumption of the heater 35 can be reduced accordingly.

Since the ceramic sleeve 31 has a high degree of electrical insulation, the capacitance between the cathode main bodies K _R , K _G , and K _B and the first grid G ₁ is also reduced, the response to high frequencies is improved, and further high definition is achieved. Can be manufactured.

When the cathode body 281 is formed by arranging the ceramic sleeve 31 vertically with respect to the ceramic substrate 37, the insertion hole 38 of the cathode body of the ceramic substrate 37 is inserted into the cathode body as shown in FIG. 5A or 5B. Body K
[K _R, K _G, K _B] an insertion portion 38a to be subjected to joining,
By a shape having a space portion 38b communicating from this, brazed portion of the cathode body K [K _R, K _G, K _B] and the ceramic substrate 37 that is, the junction area is reduced, is heated by the heater 35 Cathode body K
The heat of [K _R , K _G , K _B ] can be reduced from escaping to the ceramic substrate 37, and the efficiency of heating the electron emission portion 34 can be increased. This leads to a reduction in power consumption of the heater 35. Since having a space portion 38b, the heat treatment of the exhaust process after incorporating an electron gun in a cathode ray tube body, the cathode body K [K in the first grid G _1
R, K _G, the space portion 38b of the K _B] is released in the vicinity of the gas
Can be released to the outside. In the case of FIG. 5B, the cathode sleeve 31 of the cathode main body K is joined to the ceramic substrate 37 at three narrow places.
The heat escapes less than A.

FIGS. 9 and 10 show an electron gun 24 used in the color cathode ray tube 21 of FIG.
8 shows another embodiment. The cathode structure 282 of the electron gun according to the present embodiment is made of a ceramic material having a low coefficient of thermal expansion such as, for example, alumina, silicon carbide (SiC) aluminum nitride, or the like, and has a cylindrical shape, a rectangular shape, or the like. In the present example, a cathode sleeve formed in a square cylindrical shape in this example, a so-called ceramic sleeve 31 is also provided.
The ceramic sleeve 31 is disposed horizontally on the surface of the ceramic substrate 37 so that the axis m of the ceramic sleeve 31 extends along the surface of the ceramic substrate 37.
On the upper surface in a direction orthogonal to the axis m, an electron emission portion 34 is arranged via a metal plate 32 made of, for example, Kovar and a cathode cap 33.

Electron emission portion 34 of ceramic sleeve 31
The side end face is closed with the same ceramic material. Heater 35 is disposed in the ceramic sleeve 31, a ceramic sleeve 31, cathode body K of the horizontal structure by the electron emitting portion 34 and the heater 35 [K _R, K _G, K _B] is formed.

[0044] Each cathode body K [K _R, K _G, K _B]
The other end of the electron-emitting portion 34 is brazed to a common insulating support, that is, a pillow portion 53 provided on the ceramic substrate 37 integrally with or separately from the substrate 37, so-called cantilever. Supported. Each cathode body K [K _R, K _G, K
_B ] cantilever the ceramic sleeve 31
Of the substrate 3 in a state where most of the
It is horizontally and horizontally arranged along the seven surfaces.

Also in this embodiment, the Kovar plate 32 is connected to the ceramic sleeve 31 via a brazing filler metal made of a high-temperature active metal.
A so-called electron emission portion 34 such as an impregnated cathode member or an oxide cathode member is brazed to the Kovar plate 32.
Is welded.

[0046] On the other hand, the ceramic substrate 37, similar to the example described above, the cathode body K [K _R, K _G, K _B] so as to sandwich the pair of ceramic spacers 39A and 39B are provided integrally, A thin metal plate 44 made of, for example, Kovar is brazed to the upper surfaces of the spacers 39A and 39B. Kovar pins 41A and 41B for fixing the heater rests 40A and 40B are erected on the ceramic substrate 37 so as to penetrate the substrate 37. This Kovar pin 4
Respectively Hitaresuto 40A and 40B are electrically connected to 1A and 41B, each Hitaresuto 40A and each cathode body K _R to 40B, the heater 35 of the K _G and K _B are electrically connected. Further, the ceramic substrate 37, a cathode lead 4 from the cathode body K _R, K _G and K _B
6 is provided.

Then, as shown in FIG. 10, the cathode structure 282 of the present example has the upper surfaces of the spacers 39A and 39B,
That surface of the Kovar sheet 44 is disposed in the first grid G ₁ to abut the upper surface of the first grid G _1, the first
The grid G ₁ and the Kovar thin plate 44 on the upper surface of the spacer are welded, and the first grid G ₁ and the cathode structure 28 are joined. Further, the ceramic substrate 3 of the cathode assembly 28
7 retainer 47 for fixing the lower surface is welded to the first grid G _1, the cathode structure 282 and complete the first assembly of the grid G _1.

[0048] In the ceramic sleeve 31 cathode structure 282 are arranged in horizontal and become the elongation of the sleeve 31 to the first grid G ₁ side can be suppressed to 10μm or less.

According to the present embodiment, the color cathode ray tube 2
As the electron gun 24, in particular, as the cathode structure 28, the cathode sleeve 31 is made of a cathode material 282 made of a ceramic material having a low coefficient of thermal expansion.
Elongation of the first grid G ₁ side 1 can be suppressed. Moreover, FIG. 2 by the ceramic sleeve 31 is disposed laterally on the ceramic substrate 37 on, the elongation due to thermal expansion in the first grid G ₁ side of the sleeve 31
When placing the ceramic sleeve 31 of the embodiment of to 4 vertically 1/3 and becomes extremely small or less than, the first electron beam transmitting hole 48 of the grid G ₁ hole diameter r
It can sufficiently correspond to narrow the distance d ₀₁ of the accompanying reduction.

The elongation of the cathode sleeve 31 of the present embodiment due to thermal expansion toward the first grid side is extremely small, ie, 1/6 of that of a conventional nickel-based vertically arranged cathode sleeve.

As described above, the first of the ceramic sleeve 31
Because it can further reduce the elongation due to thermal expansion of the grid G ₁ side, it is possible to further reduce the distance d _01, that the first pore size r of the grid G ₁ further reduced narrow thinner the electron beam it can. Therefore, a higher definition cathode ray tube can be obtained.

In addition, similar to the above-described embodiment, no additional spacer is required, so that the assembling accuracy during welding can be stabilized. Ceramic sleeve 3 with high electrical insulation
Since 1 is used, the leakage current between the heater and the sleeve can be prevented, and the power consumption of the heater 35 can be reduced together with the fact that the thickness of the insulating coating of the heater can be reduced. Cathode body K and the electrostatic capacitance between the first grid G ₁ is also reduced, the response to high frequency is also better, as a result, a cathode ray tube with a higher resolution can be produced.

FIGS. 11 and 12 show the color cathode ray of FIG.
Electron gun 24 used for tube 21, especially its cathode structure
28 shows another embodiment of the present invention. Electronics according to the present embodiment
The gun cathode structure 283 is similar to the example of FIG.
For example, alumina, silicon carbide (SiC) aluminum nitride
Made of ceramic material with low coefficient of thermal expansion such as
It is formed into a cylindrical shape such as a mold and a square, in this example, a square tube.
Cathode sleeve, so-called ceramic sleeve 31
The ceramic sleeve 31 is provided on the ceramic substrate 3.
7, the axis m of the ceramic sleeve 31 is
The ceramic is placed horizontally along the surface of the
On the upper surface in a direction orthogonal to the axis m of the mix sleeve 31,
For example, a board-shaped metal plate 32 made of Kovar,
An electron emission portion 34 is arranged via a cap 33. C
A heater 35 is disposed in the lamic sleeve 31 to secure
Lamic sleeve 31, electron emission section 34 and heater 35
The horizontal structure of the cathode body K [K_R, K_G,
K _B] Is formed.

In the present embodiment, in particular, the ceramic sleeve 31 is provided on the ceramic substrate 37 at both ends integrally with or separately from the substrate 37 on two common insulating supports, namely, a pillow 53A and a pillow 53A. It is brazed so as to be supported by 53B and is supported parallel to the surface of the substrate 37, that is, horizontally. On the upper surface of the central part of the ceramic sleeve 31, an electron emission part 34 is arranged via a Kovar plate 32 and a cathode cap 33.

The heater 35 is built in so as to penetrate the ceramic sleeve 31, and each of the cathode bodies K _R , K _G ,
Both ends of the heater 35 of the K _B are electrically connected to Hitaresuto 40A and 40B disposed across the respective cathode body. The heater rests 40A and 40B are provided with Kovar pins 41A and 4A provided through the ceramic substrate 37.
1B.

[0056] Then, as shown in FIG. 12, the cathode structure 283 is inserted into the first grid G _1, it is bonded upper surface of the spacer 39A and 39B, i.e. by welding the Kovar sheet 44 of the first grid G _1, And Litina 4
7 fixed.

Since other configurations are the same as those described with reference to FIGS. 9 and 10, portions corresponding to those in FIGS. 9 and 10 are denoted by the same reference numerals, and redundant description will be omitted.

Also in this embodiment, the electron gun 24 of the color cathode ray tube 21, particularly, the cathode structure 28 thereof,
The cathode sleeve 31 is formed of a ceramic material having a low coefficient of thermal expansion, and the ceramic sleeve 31 is arranged sideways to form a cathode structure 283 having a so-called horizontal structure, as in the cathode structure 281 of FIGS. 9 and 10. it can be made extremely small elongation due to thermal expansion in the first grid G ₁ side of the cathode sleeve 31.
As a result, the distance d ₀₁ can be reduced, the hole diameter r of the first grid G ₁ can be reduced, and the electron beam can be narrowed more narrowly, so that a higher definition cathode ray tube can be obtained.

In addition, the same effects as described with reference to FIGS. 9 and 10 can be obtained.

The cathode structure 28 shown in FIGS.
In Nos. 2 and 283, the heater 35 and the heater rests 40A and 40B are not shielded on the ceramic substrate 37. However, a shield structure is possible.

In the above embodiment, the first grid G ₁
Red, green, is applied to the electron gun provided with three electron beam transmitting hole corresponding to blue, the other, corresponding to a plurality of micro electron beams transmitting hole for each color in the first grid G _1, One common cathode main body is arranged for the plurality of electron beam transmission holes, and electrons are focused from the plurality of transmission holes into one electron beam so that a large beam current can be obtained with a small drive voltage. The present invention can also be applied to a modified electron gun. In this case, if a large number of fine electron beam transmission holes are used, it is difficult to obtain a beam current unless the distance _d01 is made smaller. In the present invention by a ceramic sleeve, since the distance d ₀₁ can be made smaller, allowing the production of such an electron gun.

In the above example, the present invention is applied to a color cathode ray tube and an electron gun provided with a three-beam single electron gun. However, each grid is common to three cathode bodies, and each grid has three electron beams. So-called 3 with through-holes
The present invention is also applicable to a color cathode ray tube having a gun type electron gun and the electron gun. Further, the present invention can be applied to a cathode ray tube for a projector and its electron gun. The present invention can be applied to other high-definition cathode ray tubes and their electron guns.

[0063]

According to the electron gun of the present invention, since the cathode sleeve of the cathode main body is formed of a ceramic material having a low coefficient of thermal expansion, the elongation of the cathode sleeve due to thermal expansion toward the first grid can be reduced. . The change in dimension of the ceramic cathode sleeve in the cathode ray tube manufacturing process due to distortion during welding and the like is very small as compared with the metal cathode sleeve. Therefore, the distance d ₀₁ between the first grid and the cathode body, as compared with the case of using a conventional metal cathode sleeve, can be made smaller, thereby, the diameter of the electron beam transmission holes of the first grid Can be further reduced,
The electron beam can be focused more finely. Therefore, it is possible to manufacture a cathode ray tube with higher definition.

Since the degree of electrical insulation of the cathode sleeve is high, the capacitance between the cathode body and the first grid is also reduced,
As a result of improving the response to high frequency, it becomes possible to produce a cathode ray tube with higher definition.

Normally, the heater incorporated in the cathode sleeve is coated with an insulating material. However, since a ceramic cathode sleeve having a high degree of electrical insulation is used, no leak current flows due to contact between the heater and the cathode body. As a result, the thickness of the insulating coating can be reduced,
The power consumption of the heater can be reduced.

When the cathode sleeve made of a ceramic material is arranged horizontally on the support substrate, the expansion of the cathode sleeve due to thermal expansion toward the first grid side is further reduced, and the distance d ₀₁ between the first grid and the cathode main body is reduced. First
By making the diameter of the electron beam transmitting holes of the grid smaller, the electron beam can be narrowed more narrowly.

According to the cathode ray tube of the present invention, by providing the cathode sleeve of the cathode main body with an electron gun formed of a ceramic material, the electron beam can be narrowed more finely as described above. The capacitance between the first grids can be reduced, and higher definition can be achieved. Further, low power consumption can be achieved.

When an electron gun having a configuration in which a ceramic cathode sleeve is arranged horizontally on a support substrate is provided, the expansion due to the thermal expansion of the cathode sleeve can be further reduced, and as a result, the electron beam can be narrowed more narrowly. Further higher definition of the cathode ray tube can be achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing an embodiment of a cathode ray tube of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of a cathode structure constituting an electron gun used in the cathode ray tube of FIG.

3 is a sectional view corresponding to line A-A of FIG. 2 with the cathode structure of FIG. 2 is fixed to the first grid G _1.

4 is a sectional view corresponding to line B-B in Figure 2 of the fixed state of the cathode structure of FIG. 2 the first grid G _1.

5A and 5B are plan views of main parts of the cathode structure of FIG. 2;

FIGS. 6A and 6B are explanatory diagrams relating to the production of the cathode assembly of FIG. 2;

7A and 7B are explanatory views relating to the production of the cathode assembly of FIG. 2;

FIG. 8 is a configuration diagram showing an example of a cathode main body when using A and B oxide cathode members.

FIG. 9 is a configuration diagram showing another embodiment of a cathode structure constituting an electron gun used in the cathode ray tube of FIG. 1;

10 is a cross-sectional view corresponding to cathode structure in C-C line of FIG. 9 in the state fixed to the first grid G ₁ of FIG.

FIG. 11 is a configuration diagram showing another embodiment of a cathode structure constituting an electron gun used in the cathode ray tube of FIG. 1;

12 is a cross-sectional view corresponding with D-D line of FIG. 11 the cathode structure of a state of fixing the first grid G ₁ of FIG. 11.

FIG. 13 shows a cathode structure and a first structure of a conventional electron gun.
It is a cross-sectional view of an assembled state of the grid G _1.

[Explanation of symbols]

21 ‥‥ color cathode ray tube, 22 ‥‥ cathode ray tube, 23 ‥
‥ neck, 24 ‥‥ electron gun, 25 ‥‥ deflection yoke, K
_R, K _G, K _B ‥‥ cathode body, 28 [281,28
2,283] ‥‥ cathode structure, G ₁ ~G ₅ ‥‥ grid, C ‥‥ electrostatic convergence means, 31 ‥‥ ceramic sleeve, 32 ‥‥ kovar plate, 33 ‥‥ cathode cap, 34 ‥‥ electron emitting portion , 35 ° heater, 37
支持 Ceramic support substrate, 38R, 38G, 38B
{Insertion holes, 39A, 39B} spacers, 43} brazing material, 44} Kovar thin plate, 48} electron beam transmission holes

Claims (6)

[Claims] 1. A cathode ray tube, wherein a cathode sleeve of a cathode main body includes an electron gun formed of a ceramic material. 2. A cathode sleeve of the electron gun is vertically arranged such that an axis of the cathode sleeve is perpendicular to a plate surface of a support substrate, and an electron emission portion is provided at an upper end of the cathode sleeve in an axial direction. 2. The cathode ray tube according to claim 1, wherein the cathode ray tube is formed. 3. A cathode sleeve of the electron gun is arranged horizontally so that an axis of the cathode sleeve is along a plate surface of a support substrate, and an electron emission portion is provided on an upper surface in a direction orthogonal to the axis of the cathode sleeve. 2. The cathode ray tube according to claim 1, wherein the cathode ray tube is formed. 4. An electron gun, wherein the cathode sleeve of the cathode body is formed of a ceramic material. 5. The cathode sleeve is vertically arranged such that an axis of the cathode sleeve is perpendicular to a plate surface of a support substrate, and an electron emission portion is provided at an upper end of the cathode sleeve in an axial direction. The electron gun according to claim 4, wherein: 6. The cathode sleeve is arranged horizontally so that the axis of the cathode sleeve is along the plate surface of the support substrate, and an electron emission portion is provided on an upper surface in a direction orthogonal to the axis of the cathode sleeve. The electron gun according to claim 4, wherein: