JPH03233836A - Electron gan for cathode-ray tube - Google Patents

Abstract

PURPOSE:To eliminate an excessive working process such as repress, and improve the characteristic by forming a flat part including a part of a slit of a cylindrical electrode in the electrode wall including the slit. CONSTITUTION:A flat part 27 surrounding, at least, a part of a slit 26 of a cylindrical electrode is provided in the cylindrical electrode, and deformation in the radial direction of the cylindrical electrode by opening distortion to be generated in the slit 28 is avoided by performing press working to the cylindrical electrode. Consequently, lowering of the assembly accuracy and lowering of the characteristic of an electron gan to be caused by the generation of opening distorsion with press working of the cylindrical electron gan electrode formed with the slit 26 can be avoided. Te assembly accuracy of the electron gan can be thereby improved, and while operation characteristic can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electron gun for a cathode ray tube, and particularly to shape deformation due to processing distortion when a cylindrical electrode constituting the electron gun is processed with slits or the like. The present invention relates to an electron gun for a cathode ray tube, which avoids deterioration of characteristics caused by the deterioration of the electron gun, increases assembly accuracy of the electron gun, and improves the operating characteristics of the electron gun.

[Conventional technology]

In general, a cathode ray tube for displaying images consists of a bulb body, which consists of a panel part covered with a phosphor layer that emits light when an electron beam strikes it, a neck part connected to the panel part via a funnel part, and a bulb body that is connected to the panel part through a funnel part. It consists of an electron gun housed in the funnel, a deflection device installed near the funnel, and a correction magnetic generator group attached to the neck.

FIG. 4 is a partial cross-sectional view illustrating the structure of an electromagnetic focusing projection cathode ray tube, which is a type of cathode ray tube, in which 1 is a panel portion with a phosphor layer 10 coated on its inner surface, and 2 is a funnel portion. , 3 is a neck part, 4 is an electron gun, 5 is a deflection device (deflection yoke), 6 is a tT11 focusing magnet, 7 is a convergence yoke, 8 is a beam alignment magnet, 9
is a magnet for raster position adjustment, 10 is a phosphor layer, 11
is an electron beam.

In the figure, an electron beam 11 emitted from an electron gun 4
is deflected in the horizontal and vertical directions by the deflection yoke 5, and strikes the phosphor layer 10 deposited on the inner surface of the panel portion 1, causing the phosphor layer to emit light and forming an image. The image formed on the phosphor layer 10 is enlarged and projected onto a screen by a projection optical system (not shown). In addition, in a color image display device, the cathode ray tube and projection optical system shown in the figure are
Set up a group.

! The magnetic focusing magnet 6 focuses the electron beam from the electron gun 4, the raster position adjustment magnet 9 adjusts the raster position on the screen, and the beam alignment magnet 8 aligns the electron beam emitted from the electron gun. adjust.

FIG. 5 is a partial cross-sectional view illustrating the structure of an electrostatic focusing projection cathode ray tube, in which 1 is a panel portion with a phosphor layer 10 coated on its inner surface, 2 is a funnel portion, 3 is a neck portion, 4 is an electron gun, 5 is a deflection device (deflection yoke), 7 is a convergence yoke, 8 is a beam alignment magnet, 9 is a raster position adjustment magnet, 10 is a phosphor layer, and 11 is an electron beam.

In this figure, in this cathode ray tube, like the cathode ray tube shown in FIG. The light impinges on the phosphor layer IO deposited on the phosphor layer, causing the phosphor layer to emit light and forming an image. The image formed on the phosphor layer 10 is enlarged and projected onto a screen by a projection optical system (not shown).

The raster position adjustment magnet 9 adjusts the raster position on the screen, and the beam alignment magnet 8 adjusts the alignment of the electron beam emitted from the electron gun. Note that the electron beam of this cathode ray tube is focused by an electrostatic focusing electrode (not shown) provided in the electron gun.

FIG. 6 is a sectional view of the main parts of the electron gun in FIGS. 4 and 5, where 3 is a neck portion, 4 is an electron gun, 21 is a shield cup, 22 is a spacer contact, 23 is a getter support, and 24 is a A final accelerating electrode, 25 is a graphite layer, 26 is a slit, 28 is an electron beam passage hole, and arrow A indicates the direction of the fluorescent surface.

In the figure, an electron gun 4 housed in a neck 3 of a cathode ray tube is installed so that its center axis coincides with the neck center axis. The shield cup 21 has a cylindrical shape, and a part thereof includes a valve spacer contact 22 for supplying the anode voltage applied to the cathode ray tube to the final accelerating electrode 24. A getter support 23 and the like are attached. The bulb spacer contact 22 connects with the anode layer provided on the fluorescent surface side of the cathode ray tube and elastically contacts the graphite layer 25, which is a conductive layer coated up to the inner wall of the neck portion 3, to electrically connect the shield cup 21. The anode voltage is supplied to the final accelerating electrode 24 connected to.

The getter support 23 has the function of supporting a getter (not shown) and supplying a heating current to the getter during the getter scattering process.

A slit 26 is formed in the shield cup 21 to prevent the generation of eddy current due to the high frequency current for heating the getter during the getter scattering process. Incidentally, this slit 26 also functions as an index when setting the relative position with respect to the neck portion of the cathode ray tube.

Each electrode constituting this type of electron gun is formed by press working.

(Problems to be Solved by the Invention) The shield cup 21 has the largest diameter among the electrodes constituting the electron gun of the cathode ray tube, and is disposed close to the inner wall of the neck portion 3, as well as the spacer contact 22 and the like. High processing accuracy is required because parts such as the getter support 23 must be attached and accurately housed in a predetermined position within the neck.

In addition, this 2nd shield cup has the slit 2 mentioned above.
6 is formed, deformation occurs due to opening distortion due to the presence of this slit 26 after press working, and in order to correct this opening distortion, re-pressing is performed to ensure accuracy.

The deformation due to the above-mentioned opening strain tends to be large when the axial length h of the shield cup 21 is large.

FIG. 7 is a sectional view taken along line BB in FIG. 6 to explain the occurrence of deformation due to opening strain of the shield cup, where φDI is the original diameter in the longitudinal direction, φD2 is the original diameter in the lateral direction, φ
D is the deformed longitudinal diameter, and φD4 is the deformed lateral diameter.

As shown in the figure, the shield cup 21 has a slit 2.
6 is provided, after press working, due to the opening strain caused by the presence of this slit, φDI + φD! The vertical and horizontal diameters that should be φDff+ φD4 change, Δfi=φD
, -φD, I, ΔL=φD2−φD4, such a deformation occurs that the vertical diameter becomes smaller and the horizontal diameter becomes larger, and the cross section of the shield cup 21 becomes oval.

As a result, it may become difficult to insert the electron gun into the neck 3, or the spacer contact 22 or getter support 23 may become difficult to insert.
There are disadvantages in that there may be poor contact between the graphite layer 25 and the graphite layer 25, or the graphite layer may be scraped by the spacer contact or getter support, or in extreme cases, the inner glass wall of the neck portion may be damaged. Furthermore, there is a problem in that the characteristics of the electron gun itself deteriorate, resulting in a decrease in performance as a cathode ray tube.

In order to correct the above-mentioned opening distortion in the electron gun component processing process, it is necessary to perform re-pressing, resulting in problems with productivity such as increased production costs.

Note that the above problem occurs not only in the shield cup but also in other electrodes that require processing such as slits.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, prevent the effect of open strain from affecting the cathode ray tube assembly and the characteristics of the electron gun, eliminate the need for extra processing steps such as re-pressing, and improve the characteristics. An object of the present invention is to provide an electron gun for a cathode ray tube.

[Means for Solving the Problems] The above object is achieved by forming a flat portion including at least a portion of the slit on the wall surface of the electrode including the slit portion of the cylindrical electrode.

[Effect]

The flat portion provided on the electrode wall surface including the slit portion functions to prevent the opening strain from affecting the diameter change of the entire electrode.

As a result, the electrode diameter does not change after pressing.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the components of a shield cup explaining the first embodiment of the present invention, in which (a) is a cross-sectional view, (b) is a longitudinal cross-sectional view, 21 is a shield cup, 26 is a slit, 27
is a flat portion, and 28 is an electron beam passage hole. Also, φD
is the electrode diameter of the shield cup, and l is the flat part 2 from the electrode outer periphery.
7 (retreat amount of the flat portion 27) and Δ11 are the distances (strain release amount) between the deformed tip of the slit and the outer periphery of the electrode due to the release strain after press working.

As shown in the figure, first, the set electrode diameter of the shield cup 21 is set to φD, and the dimensions of the flat portion 27 are selected so that the strain release amount Δ11 of the slit portion 27 satisfies l≧Δ11. This dimension is determined experimentally based on the opening amount of the slit 26, the axial length, etc.

When press working is performed with the above conditions set, lΔ11≧
It can be set to 0. Deformation due to opening strain occurs only in the slit portion, and the remaining cylindrical portion that does not form the flat portion 27 is difficult to deform, so that the roundness of the shield cup as a whole is maintained.

In this way, by providing the flat portion 27 in the slit portion 26 of the shield cup 21, the release of strain due to press working occurs in the flat portion, and the dimension of the flat portion 27, that is, the retraction dimension Δ11, is adjusted to the above conditions. If set, it is possible to avoid problems during assembly of the electron gun and adverse effects on the characteristics of the electron gun caused by electrode deformation due to open strain without requiring re-pressing as in the prior art.

FIG. 2 is a cross-sectional view of a shield cup illustrating a second embodiment of the present invention, in which slits 26-1, 26-2.
6-3.26-4, each slit 26-1.26
-2.26-3.26-4 has a flat portion 27-1.27-2.27-3.2 similar to that shown in FIG.
7-4 is provided. The dimensions of the flat portion and the conditions for the amount of strain relief are the same as in the previous embodiment.

According to this embodiment, in addition to being able to balance the opening strain caused by press working and further improving the characteristics of the electron gun, the shield cup 21 is By providing slits I-26-1, 26-2, 26-3, and 26-4 at four symmetrical locations, the eddy currents generated can be reduced, and the beam alignment correction magnetic field that acts on the shield cup portion passes through the slits. Since it directly reaches the electron beam, it also has the new effect of improving correction sensitivity.

FIG. 3 is an explanatory diagram of another example of the flat portion provided in the shield cup, and FIG. It was established only in In the figure (b), the flat portion 27 is formed halfway in the axial direction from the open end of the slit. The shape of these flat portions is selected depending on the axial length and width of the slit 26, the electrode constituent material, the size of the electrode, etc., and the amount of opening strain generated.

In addition, although the embodiment of the shield cup has been described above, it goes without saying that the present invention is not limited to this and can be similarly applied to other electrodes with slits forming an electron gun. The invention is applicable not only to the projection type anode ray tube described in the embodiments, but also to other cathode ray tubes having a single electron gun, multiple electron beam cathode ray tubes, or cathode ray tubes having multiple electron guns.

[Effects of the Invention] As explained above, according to the present invention, it is possible to avoid deterioration in assembly accuracy and deterioration in electron gun characteristics caused by release strain caused by pressing of a slit-formed cylindrical electron gun electrode. We can provide cathode ray tube electron guns with excellent functionality.

[Brief explanation of drawings]

Fig. 1 shows the constituent countries of the shield cup to explain the first embodiment of the present invention, Fig. 2 is a cross-sectional view of the shield cup to explain the second embodiment of the invention, and Fig. 3 shows the flat plate provided in the shield cup. Figure 4 is a partial sectional view illustrating the structure of an electromagnetic focusing projection anode ray tube, which is a type of cathode ray tube, and Figure 5 is an electrostatic focusing projection anode. 6 is a sectional view of a main part of the electron gun in FIGS. 4 and 5; FIG. 7 is a partial sectional view illustrating the structure of the wire tube; FIG. It is a BB sectional view of. 21...Shield cup, 26...Slit,
27... Flat part, 28... Electron beam passage hole. Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] 1. In a cathode ray tube electron gun having a cylindrical electrode housed in the neck portion and having a slit extending in the axial direction in the peripheral wall, at least a portion of the slit is formed in the cylindrical electrode. 1. An electron gun for a cathode ray tube, characterized in that a surrounding flat portion is provided to avoid deformation of the cylindrical electrode in the radial direction due to opening strain caused in the slit portion by press working of the cylindrical electrode. 2. In a cathode ray tube electron gun having a cylindrical electrode housed in the neck portion and having a plurality of axially extending slits formed in the peripheral wall, at least a portion of each slit is inserted into each slit of the cylindrical electrode. The cylindrical electrode is provided with an enclosing flat part, and at least the cross section of the part provided with the flat part has a substantially polygonal shape, and the radial direction of the cylindrical electrode is caused by the opening strain generated in the slit part by pressing the electrode. An electron gun for a cathode ray tube, characterized in that deformation of the electron gun is avoided. 3. An electron gun for a cathode ray tube according to claim 1, wherein the electrode on which the flat portion is formed is a shield cup electrode. 4. Equipped with a panel section formed with a phosphor that emits light when struck by an electron beam, a neck section connected to the panel section via a funnel section, and an electron gun housed in the neck section and emitting a single electron beam. The projection cathode ray tube comprises an electrode constituting the electron gun and having a peripheral wall formed with a slit extending in the axial direction and a flat portion surrounding at least a portion of the slit, the electrode being press-processed. A projection type cathode ray tube characterized in that deformation of the electrode in the radial direction due to opening strain occurring in the slit portion is avoided. 5. The projection cathode ray tube according to claim 4, wherein the electrode on which the flat portion is formed is a shield cup electrode.