JPS6376240A - Picture tube - Google Patents

Abstract

PURPOSE:To obtain a picture tube of an excellent focus property, by making the central electron beam passage aperture of focus electrodes which form a focus lens and of an anode in an elliptical form, while making electron beam passage apertures on both sides in a form consisting of two circular arcs, straight lines, and elliptical arcs. CONSTITUTION:Three tetrode electrodes 7 are arranged at an in-line form between two electrodes 4 and 5 which compose a focus electrode set 16. An electron beam passage aperture 14 at the center is elliptical having a longer axis in the vertical direction. Two electron beam passage apertures 13 and 15 on both sides make a form connecting elliptical arcs to straight lines and two circular arcs. When electron beams are deflected by a deflecting device, the section forms are converted one by one by applying necessary signal voltages to the tetrode electrodes 7 to make the necessary section forms responding to the deflecting amount, and the spot image distorted by the deflecting aberration can be corrected easily. Since the three electron beam passage apertures 13, 14, and 15 are formed longer in the vertical direction, the effective diameter in the vertical direction is larger, and the lens aberration can be reduced. As a result, even though the electron beams are made in a vertically longer section, the deterioration of the focus property owing to the spherical aberration is not generated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides three electron beam passing holes arranged in-line at predetermined intervals in correspondence with three cathodes arranged in-line. This relates to an array of picture tubes.

[Prior Art] The focusing performance of a focusing lens in this type of picture tube is dominated by the spherical aberration of the focusing lens.

In order to reduce spherical aberration, it is required to increase the aperture of the focusing lens.

The aperture of this focusing lens is controlled by the electron beam passage hole of the focusing electrode.

In a picture tube in which three electron beam passing holes are arranged in a straight line at a predetermined interval, the aperture diameter cannot be larger than the distance between each beam passing hole, so it is necessary to reduce spherical aberration. There are limits to what you can do. This naturally places limitations on focus performance and therefore resolution.

Conventionally known means for resolving such constraints include (A) three electron beams passing through arranged in-line, as disclosed in Japanese Patent Application Laid-Open No. 80-211743; Among the holes, there is one in which the electron beam passage hole at the center has an elliptical shape, and the electron beam passage holes on both sides have a shape in which an arc on the outer side and an elliptical arc on the inner side are connected.

Furthermore, even if a focusing lens with good 1-spherical aberration is obtained,
When the electron beam passes through a deflection magnetic field after the electron gun, the cross-sectional shape of the electron beam is deformed, causing a so-called deflection aberration in which the spot image on the phosphor screen becomes non-circular.

Such deflection aberrations are particularly noticeable when the deflection magnetic field has a non-uniform distribution, such as in an in-line picture tube.

Even if the spot image at the center of the phosphor screen is circular, at the horizontal end of the center it becomes an ellipse that is horizontally elongated.

This is a conventionally known means to eliminate such deflection aberrations.

(B) A method in which a hyperbolic waveform voltage synchronized with the deflection frequency is superimposed on the focusing voltage applied to the focusing electrode of the picture tube electron gun.

(C) As disclosed in Japanese Patent Application Laid-open No. 57-84883, there is a method in which an electromagnetic coil is disposed outside the picture tube and deflection aberration is corrected through a magnetic element provided in the picture tube.

Furthermore, (D) as disclosed in Japanese Unexamined Patent Publication No. 53-9484 and I/1', a non-rotationally symmetric electric field is applied to the end of one of the electrode pairs constituting an electron lens with astigmatic characteristics. It has also been known to provide an electrode to electrostatically control an electron lens and astigmatism at the same time.

[Problems to be Solved by the Invention] Conventionally known means for eliminating spherical aberration and deflection aberration as described above have the following problems.

In other words, the means for eliminating spherical aberration shown in (A) is intended to effectively increase the aperture diameter of the focusing lens, although it has an unusual shape. However, in the case of such irregularly shaped holes, even if a numerical control method is used, the hole edge is a curve that changes continuously due to the connected shape of circular arcs and elliptical arcs, so the reference point is ambiguous and it is difficult to actually It is difficult to inspect and measure the shape of the drilled holes and the mutual arrangement of the three holes when drilling the holes.

Therefore, when assembled with other electrodes to form an electron gun, the electron beam may be eccentric to the electron beam passage hole of the other electrodes, or
This tends to cause tilting, which is a major obstacle to the yield and performance characteristics in the picture tube manufacturing process, making it difficult to put it into practical use.

Furthermore, although the means for eliminating deflection aberration shown in (B) can adjust the focal length of the condenser lens, it is hardly effective in eliminating deflection aberration.

The means for eliminating deflection aberration shown in (C) requires high costs for electromagnetic coils, etc., and also consumes a large amount of power.
This is a problem that requires some way to avoid interference with the deflection magnetic field.

Furthermore, in the case of the simultaneous control means for electronic lens and astigmatism shown in (D), there is a problem that waveform voltages for achieving different purposes interfere with each other in electric field formation. In order to eliminate such mutual interference, it is necessary to superimpose waveform voltages for correcting the interference in synchronization with the deflection frequency, which complicates the operating circuit. Furthermore, in an in-line color cathode ray tube, static convergence is generally performed electrostatically in the electron lens region, so this method has the problem that static convergence is disrupted by changes in the focusing electrode potential.

This invention was made to solve the above-mentioned problems, and it improves focus performance without impairing the basic performance of electron guns such as acceleration, focusing, and concentration, and while enabling high-precision processing and assembly. The purpose of this project is to provide an excellent picture tube.

[Means for Solving the Problems] The picture tube according to the present invention directs the electron beam on both sides and above and below within the drift space between the focusing electrodes, which are made up of two electrodes arranged one behind the other along the axis of the electron beam. A quadrupole electrode consisting of a pair of vertical electrode pieces and a horizontal electrode piece each sandwiched between the three electron beam passing holes in the focusing electrode and the anode forming a focusing lens,
The center electron beam passage hole is shaped like an ellipse with its long axis perpendicular to the inline arrangement direction, and the electron beam passage holes on both sides are formed by two circular arcs sandwiching a straight part and the opposite side of the straight part. It is characterized by being formed into a shape consisting of an elliptical arc connected to the two circular arcs.

[Function] In this invention, when a voltage for correcting a hyperbolic waveform synchronized with the deflection frequency is applied to the quadrupole electrode, an electric field is formed at the quadrupole electrode due to the applied voltage, and while the electron beam passes through this electric field space, The cross-sectional shape of the electron beam changes to a shape corresponding to the signal voltage due to electrostatic attraction or repulsion.

In addition, all of the electron beam passing holes in the focusing electrode are formed vertically in the direction perpendicular to the inline arrangement direction, so the effective lens diameter in the vertical direction is large and lens aberration can be reduced, so that the electron beam is When the electron beam is scanned in a vertical direction, the electron beam is not affected by the aberration of the focusing lens even if the quadrupole electrode has a vertically elongated cross-sectional shape to correct the deflection aberration.

In addition, the straight line of the electron beam passage hole of the focusing electrode serves as a clear reference line for numerical control type 1 machine tools, commonly known as NG grinding machines, etc. used when actually drilling holes, and it starts from a straight line. A series of machining methods such as moving from a circular arc to an elliptical arc, then returning to a straight line after passing through the next circular arc can be used, allowing for highly accurate hole machining.

In addition, when inspecting the shape of the machined holes, etc., we use an NC three-dimensional coordinate measuring machine to perform highly accurate inspections, as described above.
Measurements can be made.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a schematic diagram of an electron gun in a picture tube according to an embodiment of the present invention. In the figure, (1) is three cathodes arranged in-line at predetermined intervals. (2) is a control electrode, (3) is an acceleration electrode, (1B)
is a focusing electrode, which consists of two electrodes (4) and (5) placed one behind the other along the axis of the electron beam. (6) is an anode.

Various of the above (1), (2), (3), (1B), (8)
(7) is a quadrupole electrode, and the two front and rear electrodes (4), which constitute the focusing electrode (18),
5) Three pieces are arranged in-line between them. The two electrodes (4) and (5) before and after are electrically connected by a connecting wire (8) and held at the same potential.

As shown in FIG. 2, each of the three quadrupole electrodes (7) has four electrode pieces (9), (9), (10) arranged along the axis through which the electron beam passes. , (10). In other words, it is composed of a pair of vertical electrode pieces (10), (10) that sandwich the electron beam from both sides, and a pair of horizontal electrode pieces (9), (9) that sandwich the electron beam from above and below, and each has a vertical electric field. and a horizontal electric field.

The rear electrode (5) of the focusing electrode (16) and the anode (8) constituting the focusing lens each have three electron beam passing holes (13) arranged in-line at predetermined intervals; (14) and (15). These three electron beam passage holes (13), (14), and (15) are formed as described in detail below.

As clearly shown in Figure 3, the central electron beam passage hole (1
4) converts the two elliptical arcs (14a) and (14a) into avi
The two electron beam passing holes (13) and (15) on both sides are elliptical in shape and have long axes perpendicular to the inline arrangement direction.
a), and connect two circular arcs (13b) and (15b) respectively across the straight parts (13a) and (15a), and on the opposite side to the straight parts (13a) and (15a), the above two arcs are connected. arcs (13b), (15b) and elliptical arcs (1
3c) and (15c) are connected. The electron beam passing holes (13), (15), (7) elliptical arcs (13c), (15c) on both sides are the same as the two elliptical arcs (14a), (14a) of the central electron beam passing hole (14).
) sides, and those elliptical arcs (14a),
It has a larger radius of curvature than (14a).

and two elliptical arcs (14a) of the central electron beam passage hole (14), approximately the center of (14a), and
The above two electron beam passing holes (13), (15) on both sides
), the straight line parts (13a), (15a) and the elliptical arc (
13c) and (15c), the center line of the in-line arrangement passes through the approximate center of each of them.

Note that the three electron beam passing holes of the anode (8) are also exactly the same as those described above.

In the picture tube configured as described above, the electron beam emitted from the cathode (1) becomes an electron beam while the flow rate is adjusted while passing through the opening of the control electrode (2) and the opening of the accelerating electrode (3). The front electrode (0) of the focusing electrode travels inside the focusing electrode through the opening, receives a focusing action in the boundary region with the anode (6), and projects a spot image on a fluorescent surface (not shown). .

Since the potential within the focusing electrode is maintained at the same potential, the electron beam drifts.

One of the quadrupole electrodes (7) arranged in this drift space, for example, horizontal electrode pieces (9), (Ill) and vertical electrode pieces (10
), (10), when an electron beam with a circular cross section (11) as shown in Fig. 2 passes through the quadrupole electrode (7), the vertical cross section (12) is created by the electrostatic field. When the electron beam is deflected to the periphery, the aberration that results in a horizontally long cross section on the phosphor screen is corrected in advance before deflection. Since this action takes place in the drift space, it does not essentially accelerate or decelerate the electron beam, and without impairing the focusing function of the electron gun, it simply changes the spot cross section and changes the trajectory within the focusing lens.

Therefore, when projecting a spot image at the center of the phosphor screen, the circular cross section (11) is not changed by the quadrupole electrode (7), and when the electron beam is deflected by a deflection device (not shown), the deflection The cross-sectional shape is successively changed by applying a necessary signal voltage to the quadrupole electrode (7) so that the required cross-sectional shape corresponds to the amount. In this way, a spot image distorted by deflection aberration can be easily corrected.

The secondary electrode (5) of the focusing electrode (10) constituting the focusing lens
) and an aperture through which the electron beam of the anode (6) passes, that is, three electron beam passing holes (13).

(14) and (15) are both vertically long, so they have a large effective aperture in the vertical direction and can reduce lens aberration, so even if the electron beam is made vertically long (12), the focus performance will not deteriorate due to spherical aberration. It doesn't happen.

Also, the three electron beam passing holes (13).

Since the shapes of (14) and (15) are as described above, the electron beam passing holes (13) and (15) on both sides are
When processing and forming with a C-equipped grinder, one straight part (13a
) as a starting point, the process moves from the circular arc (13b) to the elliptical arc (13c), returns to the straight part (13a) via circle 1 (13b) again, and then the straight part (13
Using a) as a reference point, process the other straight part (15a) using a numerical control method, and use this straight part (15a) as a starting point to form a circular arc (15b) and an elliptical arc (15c) in the same manner as described above.
, the arc (15b) is processed.

Further, the central electron beam passage hole (10) is formed by processing two elliptical arcs (14a), (14a) using the two straight portions (13a), (15a) as reference points.

In addition, although the case where processing and forming is performed using an NC-equipped grinding machine has been described above, the thin plate pressing method that is commonly used may also be adopted. In this case, in the production of the press mold, , (15a) can be used as a processing standard to manufacture a press mold with high precision.

Furthermore, in the inspection after machining of the electron beam passage hole,
A highly accurate inspection can be performed based on a clear reference point using the same procedure as described above.

[Effects of the Invention] As described above, according to the present invention, since the action of the quadrupole electrode is performed electrostatically in the drift space, the basic performance of the electron gun such as focusing and concentration is not disturbed, and static convergence can be prevented. Deflection aberration can be corrected without destroying the image.

In addition, since the above-mentioned quadrupolar action is performed electrostatically, there is no need for expensive attached elements such as electromagnets, and there is no power consumption, making it extremely economical. Furthermore, since the quadrupole electrode is located within the focusing electrode, It can be operated with a signal voltage as low as the focusing voltage.

Furthermore, since the back electrode of the focusing electrode that constitutes the focusing lens and the electron beam passing hole of the anode are formed vertically, the effective aperture in the vertical direction is large and the vertical lens aberration can be reduced, so that the electron beam can be Even if the cross section is made vertically long, focus performance does not deteriorate due to spherical aberration.

Therefore, even if the deflection aberration is corrected by the quadrupole electrode, there is no deterioration in focus performance due to the spherical aberration of the lens, and a good spot image of the electron beam can be obtained over the entire area of the phosphor screen.

Furthermore, when machining the three electron beam passing holes of the rear electrode of the focusing electrode and the anode, there is a straight line that serves as a clear reference point, so it is possible to process the hole shapes and mutual arrangement with high precision. And therefore also. The assembly accuracy of the electron gun is also good, which has a great effect on improving yield and performance characteristics.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an electron gun in a picture tube according to an embodiment of the present invention, FIG. 2 is an enlarged configuration diagram of the main part explaining the configuration and operation of the quadrupole electrode, and FIG. 3 is a diagram showing the rear part of the focusing electrode. This is an enlarged perspective view of the side electrodes. (1)... cathode, (2)... control electrode, (3)...
・Acceleration electrode, (4)...Front side 'F! , pole, (5)...
- Rear electrode, (6)... anode, (7)... quadrupole conduction, (9... horizontal electrode piece, (10)... vertical electrode piece,
(+3), (+41. (15)...Electron beam passing hole, (13a), (15i,, , J, line part, (;
3b), (15b)...Circular arc, (13c), (1
5c), (14a)"・Elliptical arc, (1B) -...
Focusing electrode. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A picture tube comprising three cathodes arranged in-line, a control electrode, an accelerating electrode, a focusing electrode, and an anode each having three electron beam passing holes arranged in-line, the focusing electrode The electrode consists of two electrodes arranged one behind the other along the axis of the electron beam, a pair of vertical electrode pieces arranged along the axis through which the electron beam passes and sandwiching the electron beam from both sides, and a pair of vertical electrode pieces arranged along the axis through which the electron beam passes. Three sets of quadrupole electrodes each consisting of a pair of horizontal electrode pieces sandwiched from above and below are sandwiched between the two front and rear electrodes, and the center of the three electron beam passing holes of each of the rear electrode of the focusing electrode and the anode is The electron beam passing hole is formed in an elliptical shape by connecting two elliptical arcs with long axes perpendicular to the inline arrangement direction, and the electron beam passing holes on both sides are formed by two circular arcs sandwiching a straight part. and formed into a shape consisting of an elliptical arc connected to the two circular arcs on the opposite side to the straight line part,
The elliptical arcs of the electron beam passage holes on both sides face the elliptical arc side of the central electron beam passage hole, and are in contact with the two elliptical arcs of the central electron beam passage hole and the straight portions of the electron beam passage holes on both sides. A picture tube characterized in that each of the picture tubes is configured such that the center line of the inline arrangement passes through substantially the center thereof.