JPH01264144A - Flat plate type cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain an optimumly focused electron beam spot over the whole fluorescent screen by constituting multiple face-shaped electrodes and a plate- shaped electrode so as to pinch an electron beam and applying a fixed focusing action to the electron beam in the scanning direction at the time of scanning and deflecting in the emitting direction of the electron beam. CONSTITUTION:Multiple face-shaped electrodes 4 slenderly divided in the horizontal direction are vertically arranged at the preset interval in parallel with a fluorescent screen 2 in the back panel section 3 of a vacuum container. A plate- shaped electrode 5 is arranged in parallel with the fluorescent screen 2 between the fluorescent screen 2 and the face shaped electrodes 4, multiple vertically slender openings 50 are arranged at the preset interval in the horizontal direction on the plate-shaped electrode 5. An electron beam straightly proceeds in the region pinched by the face-shaped electrodes 4 and the plate-shaped electrode 5 and is deflected toward the fluorescent screen 2 at the position of the face-shaped electrodes 4 applied with the preset voltage. The deflecting voltage to scan the electron beam is applied to the face-shaped electrodes 4, and also the voltage of the plate-shaped electrode 5 is controlled. An optimumly focused electron beam spot can be obtained over the whole fluorescent screen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to negative Ti and S tubes used in color television receivers, computer terminal displays, and the like.

In particular, it relates to flat cathode ray tubes.

[Conventional technology]

As a conventional flat cathode ray tube, for example, JP-A-60-8
There is one shown in Publication No. 9041. This conventional example will be explained below using the cross-sectional view shown in FIG.

A fluorescent surface 2 is provided on the inner surface of the transparent face portion 1 of the vacuum container 31.
is formed. On the inner surface of the back panel section 3, which is provided parallel to the fluorescent surface 2.

A plurality of deflection electrodes 41 elongated in one direction are arranged in stripes. Between the fluorescent surface 2 and the deflection electrode 41, a modulation electrode group 51 is arranged parallel to the fluorescent surface 2. Further, at one end of the deflection region sandwiched between the deflection electrode 41 and the modulation electrode group 51, a linear cathode 7. Beam extraction electrode 8
1. Back electrode 9° prefocus electrode 82. An electron gun consisting of a focus electrode 83 and a shield electrode 84 is provided. The voltage of the deflection electrode 41a closest to the electron gun and the voltage of the deflection electrode 41 side of the modulation electrode group 51 are both kept at the same constant voltage, and the voltage of the deflection electrode 41n farthest from the electron gun is lower than the above constant voltage. Fixed to low voltage. The voltage from the remaining deflection electrode 41b to the deflection electrode 41m can be freely changed between the constant voltage and the low voltage.

The electron beam 10 emitted from the electron gun initially hits the fluorescent surface 2.
It travels straight in the deflection area parallel to.

It is deflected at a position selected by the deflection electrode 41 and reaches the fluorescent surface 2. That is, from the deflection electrode 41b to the deflection electrode 4
1i to the above constant voltage and the voltage from the deflection electrode 41j to the deflection electrode 41m to the above-mentioned low voltage, the electron beam 10 travels straight to the vicinity of the deflection electrode 41i, and the fluorescent surface 2 at the position of the deflection electrode 41j. deflect towards. This deflection position moves toward the adjacent deflection electrode 41 as the voltage of the deflection electrode 41j is changed from the low voltage to the constant voltage. At the same time, the position of the electron beam spot on the fluorescent surface 2 also moves, and scanning is performed by an amount equal to the arrangement pitch of the deflection electrodes 41.

By sequentially switching and applying the deflection voltage for scanning the electron beam 1o to the adjacent electrodes from the deflection electrode 41b to the deflection electrode 41m in this manner.

A full scan is performed.

[aM that the invention attempts to solve]

In the conventional example described above, it is difficult to keep the electron beam spot diameter constant over the entire area of the fluorescent surface 2. That is, in FIG. 6, as the magnitude of the deflection voltage applied to the deflection electrode 41 is changed, the focusing state of the electron beam 10 changes, and the size of the electron beam spot in the scanning direction changes as well as the arrival position of the electron beam. FIG. 3 shows an example of such a change in the electron beam diameter.

As the deflection voltage changes, the beam diameter doubles or more at maximum, and the resolution on the fluorescent surface 2 deteriorates. One way to solve this problem is to make the number of deflection electrodes 41 equal to the number of scanning lines.

According to this method, 1! Scanning can be performed without changing the focusing state of the child beam. However, since the number of electrodes increases significantly, manufacturing and driving become extremely difficult.

In particular, in the conventional example shown in FIG.
The deflection electrode 41n is characterized in that the electrode width in the arrangement direction is wider than the width of the other deflection electrodes 41, and the voltage is always kept constant. This is done in consideration of the fact that the uniformity of the deflection effect deteriorates due to differences in the deflection electrodes 41 that select the deflection position of the electron beam 10. However, since the electron beam 10 reaches the fluorescent surface 2 after traveling in the emission direction to some extent after it begins to be deflected, the wider the deflection electrode 41a, the longer the distance it takes to reach the fluorescent surface 2. Therefore, a problem arises in that a dead space in which one image cannot be displayed increases between the electron gun and the fluorescent surface 2.

[Means to solve the problem]

The present invention aims to solve the above-mentioned problems.

A deflecting means for scanning an electron beam emitted almost parallel to the fluorescent surface in the emission direction and deflecting it toward the fluorescent surface is provided with a plurality of deflecting means separated in the scanning direction of the electron beam. A planar electrode and a root-like electrode provided with a plurality of electron beam passage holes are configured to sandwich the electron beam, and a voltage is applied to the electrode so that the focusing effect in the scanning direction is constant during scanning and deflection of the electron beam. The voltage is applied to each of the above-mentioned planar electrode and the above-mentioned plate-like electrode.

[Effect]

The electron beam emitted almost parallel to the fluorescent surface travels straight through the region sandwiched between the planar electrode and the plate electrode, and emits a fluorescent light at the location of the planar electrode to which a predetermined voltage is applied. Deflect towards the light plane. At this time, a deflection voltage for scanning the electron beam is applied to the planar electrode, and at the same time, the voltage of the plate electrode is controlled. As a result, the electron beam is subjected to a certain focusing effect upon deflection, so that an optimally focused electron beam spot can be obtained on the gold region of the fluorescent surface.

〔Example〕

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

FIG. 1 is a partially cutaway perspective view schematically showing the internal structure of a flat cathode ray tube according to an embodiment of the present invention. The face part 1 of the vacuum container is made of a transparent material such as glass, and on its inner surface, a fluorescent surface 2 is formed by applying 3M color (red, green, and blue) phosphor in vertical stripes. There is. Inside the back panel portion 3 of the vacuum container, a plurality of horizontally divided planar electrodes 4 are arranged vertically parallel to the fluorescent surface 2 at predetermined intervals. A constant voltage Vn is applied to these planar electrodes 4 independently of each other.
e Vz and the periodically changing voltage Vo can be sequentially switched and applied. Fluorescent surface 2
A plate-shaped electrode 5 is arranged parallel to the fluorescent surface 2 between and the planar electrode 4 . This plate-shaped electrode 5 is provided with a plurality of vertically elongated openings 50 at predetermined intervals in the horizontal direction. Further, between the fluorescent surface 2 and the plate electrode 5, a plurality of vertically elongated horizontal deflection electrodes 6 are arranged parallel to each other so as to be located between two adjacent elongated openings 50. . These horizontal deflection electrodes 6 are electrically connected to each other so that different voltages can be applied alternately to adjacent electrodes. Further, at one end in the vertical direction of the deflection region sandwiched between the planar electrode 4 and the plate electrode 5.

Linear M1 pole stretched in the horizontal direction7. Beam extraction electrode 8. An electron gun consisting of a back electrode 9 is provided.

In this embodiment, the fluorescent surface 2 may be formed on a transparent substrate separate from the face section 1 of the vacuum container, and the one-plane electrode 4 may be arranged independently from the back panel section 3. Furthermore, instead of the linear cathode 7, it is also possible to configure the electron gun with a plurality of cathodes, each of which emits an electron beam.

The beam extraction electrode 8 has an elongated opening 5 in the plate electrode 5.
0, a plurality of openings are provided that are lined up at predetermined intervals in the horizontal direction. The linear cathode 7 is disposed so as to pass directly below the center of the opening of the beam extraction electrode 8, and is supported by a support that prevents loosening due to vibration or thermal expansion. They are each fixed at a predetermined distance from the back electrode 9. The back electrode 9 is electrically divided in the horizontal direction corresponding to the aperture of the beam extraction electrode 8, and a voltage lower than the potential of the corresponding portion of the linear cathode 7 by 0 to several tens of V is applied to each portion. When the voltage of the back electrode 9 is sufficiently low, no thermoelectrons are emitted from the corresponding portion of the linear wire #M7, resulting in a cut-off state. When the voltage of the back electrode 9 is increased, thermoelectrons are emitted, and the amount of thermoelectrons emitted is controlled by the magnitude of the voltage. Thermionic electrons released.

The electron beams are extracted from the opening of the beam extraction electrode 8 into the deflection region as independently modulated electron beams. In particular, in this embodiment, a protrusion 8o is provided in the opening provided in the beam extraction electrode 8, so that the focusing effect around the central axis of the electron beam is non-axially symmetrical. This is the horizontal position of the electron beam spot created on the fluorescent surface 2.

This is to easily balance the spot diameter in the vertical direction. Therefore, such a protrusion 80 may be omitted,
There is no problem simply providing a circular opening.

FIG. 2 is a vertical sectional view of a part of the deflection region sandwiched between the planar electrode 4 and the plate electrode 5 in the embodiment shown in FIG. In the order in which they are lined up in the direction, up to the planar electrode 41, the voltage 1 for making the electron beam 10 go straight is applied, and the electrodes after the planar electrode 4k after one gap are applied with a predetermined voltage lower than the voltage v. The voltage v1 to the voltage v
A deflection voltage Vp varying up to 2 is applied. Further, a voltage Vp that changes from the voltage v1 to a lower voltage Vδ is applied to the plate electrode 5. When the voltage VD is currently 1, the electron beam 10 travels straight to the planar electrode 4j, and is then deflected toward the fluorescent surface 2 under the influence of the low voltage v2. At this time, the position where the electron beam 10 passes through the elongated opening of the plate-shaped electrode 5 is point A in the figure. Next, when the magnitude of the voltage Vo is changed from Vl to v2, the deflection position moves toward the planar electrode 41, and the position where the electron beam 1o passes through the elongated opening of the plate electrode 5 also changes as shown in the figure. Move from point A to point B. This amount of movement is exactly equal to the arrangement pitch of the planar electrodes 4. If such a deflection voltage Vo is sequentially switched and applied to the adjacent planar electrodes 4, the passing position of the electron beam will move throughout the vertical direction. , scanning on the fluorescent surface 2 can be performed.

FIG. 3 is a diagram showing the relationship between the deflection voltage Vo and the vertical beam diameter of the electron beam passing through the plate electrode 5 in the embodiment shown in FIG. The horizontal axis in Fig. 3 shows the deflection voltage V
The vertical axis represents the beam diameter in the vertical direction when a laminar flow beam with a diameter of 1 m emitted from the electron gun is deflected and passes through the plate electrode 5. The value of the lower voltage vlt mentioned above is chosen to be Ov. When the voltage VF of the plate electrode 5 is kept constant, the beam diameter also changes as the deflection voltage Vo changes. If such a change in beam diameter is large, the resolution in the vertical direction on the fluorescent surface 2 will deteriorate. However, when changing the deflection voltage VD, if the voltage VF of the plate electrode 5 is also changed accordingly, the focusing effect in the vertical direction becomes constant, and scanning is performed while keeping the electron beam diameter constant. becomes possible.

That is, as shown in FIG. 3, for example, point C and point [
) have different combinations of voltage Vo and voltage VF, but have the same beam diameter. Therefore, the deflection voltage V
When changing o, the vertical beam spot diameter on the fluorescent surface 2 can always be kept constant by appropriately selecting and changing the value of the voltage VF so that the beam diameter remains constant.

FIG. 4 shows an example of a suitable combination of deflection voltage Vo+voltage VF. On the horizontal axis of FIG. 4, the ratio of the deflection voltage Vo to the voltage 1 is plotted.

The value of voltage Vp at which the beam diameter becomes constant is expressed as a ratio to voltage Vz. Deflection voltage ratio is 100%
During the change, the plate electrode voltage ratio may be changed to a value as low as 5%. The actual magnitude of the plate electrode voltage VF is
Even when the voltage Vz for making the electron beam go straight is 1 kV, it is only about 50 V and there is no particular problem in terms of one circuit. On the other hand, in the upper part of FIG. 4, the position of the electron beam passing through the plate electrode 5 is shown as a ratio to the arrangement pitch of the planar electrode 4. The passing position of the electron beam is expressed based on the time when the deflection voltage Vo=O, and the upward direction in the vertical direction is positive. For example, if this deflection voltage VD is
If they are added to the planar electrode 4j shown in the figure, points A2 and B in FIG. 2 correspond to points A2 and B in FIG. 4, respectively. Although the change in the electron beam passing position with respect to the deflection voltage Vo is not linear, if the amount of change in the voltage VD is adjusted over time, the electron beam passing position can be moved at a constant speed.

As described above, according to the present invention, when the electron beam is vertically scanned, the focusing effect in the scanning direction can be kept constant, thereby eliminating the conventional deterioration in vertical resolution. Furthermore, even if the planar electrode to which the deflection voltage VD is applied is closest to the electron gun, it is possible to control the plate electrode voltage VF so that uniformity of electron beam focusing is maintained. therefore.

According to the present invention, the planar electrode closest to the electron gun can be configured and driven in substantially the same way as the other electrodes, so there is no increase in dead space as in the conventional example.

In this example, a deflection voltage Vo, which changes from the voltage Vz for making the electron beam go straight to a voltage v2 lower than normal, is applied to the divided planar electrodes arranged in the vertical direction from top to bottom. We have shown a method of sequentially switching and adding in the direction of . On the contrary, it is also possible to apply a deflection voltage Vo that changes from voltage v2 to voltage Vz, which is lower than the voltage v1 for making the electron beam go straight, to the adjacent planar electrodes by sequentially switching from bottom to top. It is. However, in this case, 1N! The daughter beams are scanned from bottom to top over the fluorescent surface.

The electron beam that passed through the elongated aperture 50 of the plate-shaped electrode 5 is
Subsequently, it is deflected in the horizontal direction by the horizontal deflection electrode 6 and reaches the fluorescent surface 2. In the embodiment shown in FIG. 1, the horizontal deflection electrode 6 is provided with a voltage that is obtained by superimposing a voltage Vz for making the electron beam to travel straight and a horizontal deflection voltage VH that periodically oscillates in positive and negative directions with different signs, and every other voltage is applied to the horizontal deflection electrode 6. is applied to. Since each horizontal deflection electrode 6 contributes to the deflection of two electron beams, adjacent electron beams are scanned in opposite directions in the horizontal direction. In order to display television images using this method, a memory for at least one horizontal scanning line is required, but there is no particular problem in terms of circuitry. Also,
Since the voltage Vz and the horizontal deflection voltage VH are several percent of the voltage of the fluorescent surface 2, a lens is formed between the fluorescent surface 2 and the horizontal deflection electrode 6 to focus the electron beam in the horizontal direction. By balancing this lens action and the horizontal focusing action in the electron gun, an optimally focused electron beam spot can be obtained on the fluorescent surface 2. In addition.

By applying a parabolic correction voltage to each electrode in addition to the horizontal deflection voltage Vo, the focusing effect is corrected according to the amount of deflection, making it possible to perform scanning with a constant spot diameter even during large-angle deflection.

In this embodiment, one independent horizontal deflection electrode 6 is arranged as means for scanning and focusing in the horizontal direction. Each deflection electrode contributes to the deflection of two electron beams. However, in this case, a structure may be arranged in which two deflection electrodes are pasted together with an insulating plate interposed therebetween and independent voltages are applied to each.

The individual deflection electrodes are alternately electrically connected to apply a deflection voltage. Therefore, the electron beam is always scanned horizontally in the same direction.

Next, another embodiment of the present invention will be described using a partially cutaway perspective view shown in FIG.

Face part 1. Inside the vacuum container including the back panel part 3, a fluorescent surface 29 and a planar electrode 4. A plate-shaped electrode 5 is arranged. Further, at one end in the vertical direction of the deflection region sandwiched between the planar electrode 4 and the plate electrode 5, a linear cathode 7. Beam extraction electrode 81. An electron gun consisting of a back electrode 9 is provided. Furthermore, a fluorescent surface 2 and a plate-shaped electrode 5
In this embodiment, a modulation electrode group 51 consisting of a plurality of electrodes is arranged parallel to the fluorescent surface 2. In this embodiment, instead of the horizontal deflection electrode 6 provided in the embodiment of FIG. Therefore, the modulation electrode group 51 functions to focus the electron beam in the horizontal direction. Therefore, the electron beam extraction electrode 81 may also have a simple configuration, and is simply composed of an electrode provided with a circular beam extraction aperture. Providing such a modulation electrode group 51 has the advantage that the influence of the voltage VF applied to the plate electrode 5 when scanning and deflecting the electron beam can be reduced. That is, in the embodiment shown in FIG. 1, the plate electrode 5. Horizontal deflection electrode 6. Since the horizontal focusing effect of the electron beam is influenced by the voltage relationship of the fluorescent surface 2,
Voltage changes on the plate electrode 5 have a slight effect on the electron beam spot diameter in the horizontal direction. In contrast, in this embodiment, the voltage change of the plate-like electrode 5 is completely shielded by the modulation electrode group 51, so that it has almost no effect.

In the above detailed explanation of the present invention, a configuration in which vertical scanning is performed using a one-divided planar electrode has been shown. It is also possible to operate these planar electrodes to perform horizontal scanning. Furthermore, in all of the embodiments of the present invention, a method is shown in which color selection is performed by temporally switching the electron beam that hits three color phosphor stripes by deflection, but it is possible to It is also possible. Further, in the present invention, a method of scanning an electron beam using a plurality of planar electrodes has been described, but the present invention can also be easily applied to a method of scanning using a single planar electrode.

〔Effect of the invention〕

According to the present invention, when scanning and deflecting the emission direction of the electron beam, a certain focusing effect can be given to the electron beam in the scanning direction, so that an optimally focused electron beam spot can be obtained over the gold area of the fluorescent surface. be able to. In addition, since it can be constructed using a smaller number of planar electrodes than conventional examples, it is advantageous in terms of uniform control of multiple electron beams and in terms of manufacturing. Can provide tube.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of an embodiment of the present invention. 2 is a vertical sectional view of a part of the embodiment of FIG. 1, FIG. 3 is a diagram showing changes in the electron beam diameter in the embodiment of FIG. FIG. 5 is a partially cutaway perspective view showing another embodiment of the present invention, and FIG. 6 is a cross-sectional view of a conventional flat cathode ray tube. be. 1... Face part, 2... Fluorescent surface, 3 Back panel part. 4... Planar electrode, 5... Plate electrode, 6... Horizontal deflection electrode, 7... Linear cathode, 8.81... Beam extraction electrode, 9... Back electrode, 10 ...electron beam,
31... Vacuum container, 41... Deflection electrode, 51...
Modulation electrode group, 82... pre-focus electrode, 83...
・Focus electrode, Fig. 1, 5 sheets, 1 input voltage, Fig. 2, gj-3, deviation amount, Th/v, (ri), Fig. 6, 1,4 ward.

Claims (1)

[Claims] 1. A fluorescent surface, a means for emitting a plurality of electron beams substantially parallel to the fluorescent surface, and a means for scanning the electron beams in the emitting direction and directing the electron beams toward the fluorescent surface. at least a deflection means for deflecting the electron beam, the deflection means being provided to sandwich the electron beam between the electron beam and the fluorescent surface,
a plurality of planar electrodes divided in the scanning direction;
a plate-like electrode provided with a plurality of apertures through which the electron beam passes, the electrode being arranged to sandwich the electron beam between the electrode and the planar electrode; A flat cathode ray tube characterized in that a voltage is applied to at least one of the planar electrodes and at the same time a voltage is applied to the plate electrodes so that the focusing effect in the scanning direction becomes constant. 2. At the same time, a voltage that changes from voltage V_1 for making the electron beam go straight to voltage V_2 lower than the voltage V_1 is applied to at least one of the planar electrodes, and at the same time, the 2. The flat cathode ray tube according to claim 1, wherein a voltage is applied such that the voltage decreases once from voltage V_1 to voltage V_3 lower than said voltage V_1, and then changes again to said voltage V_1. 3. At least one of the planar electrodes is applied with a voltage that changes from voltage V_2, which is lower than the voltage V_1 for making the electron beam go straight, to voltage V_1, and at the same time, the plate-shaped electrode is applied with the voltage V_1. 2. The flat cathode ray tube according to claim 1, wherein a voltage is applied such that the voltage decreases once from voltage V_1 to voltage V_3 lower than said voltage V_1, and then changes again to said voltage V_1.