JPH0528461B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cathode ray tube (CRT) for use in oscilloscopes, storage oscilloscopes, etc.
More specifically, the present invention relates to a deflection magnifying electron lens for a cathode ray tube.

[Conventional technology and its problems]

Placing a cylindrical deflection magnifying electron lens between the deflection system and the screen is known, for example, as disclosed in Japanese Patent Application Laid-Open No.
Publication No. 134531, Japanese Patent Publication No. 60-65436, Japanese Patent Publication No. 1986-65436
It is disclosed in Publication No. 60-23939 and the like. The first deflection-magnifying electron lens disclosed in JP-A-59-134531 includes two cylindrical electrodes constituting a quadrupole lens, and further has a slot lens at the entrance of the quadrupole lens and an aperture lens at the exit. Therefore, the structure of this deflection magnifying lens is very complicated, and the usable effective diameter of the lens is small.

On the other hand, the deflection magnifying electron lenses disclosed in Japanese Patent Application Laid-open Nos. 60-65436 and 60-23939 include a quadrupole lens consisting of electrodes with a rectangular cross section, and have a relatively simple structure. However, a specific method for producing an electron lens with high sensitivity and short overall length is not disclosed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a highly sensitive deflection magnifying lens with a relatively simple configuration and to shorten the total length of a CRT.

[Means for solving problems]

To achieve the above object, the present invention will be described with reference to the reference numerals in the drawings showing the embodiments.
a first deflection system that deflects the electron beam emitted from the electron gun in a first direction; and a second deflection system that deflects the electron beam in a second direction orthogonal to the first direction.
a screen for impacting the electron beam emitted from the electron gun; and a deflection magnifying electron lens disposed between the deflection means and the screen; The magnifying electron lens consists of first and second cylindrical electrodes 18 and 19 arranged coaxially, and the first cylindrical electrode 18 has the first direction as the y-axis and the second direction as the y-axis. If x-axis is the traveling direction of the electron beam without deflection, and z-axis is the traveling direction of the electron beam without deflection,
A first pair of surfaces 2 arranged symmetrically around the z-plane
1, 22, and a second pair of surfaces 23, 24 arranged symmetrically about the y-z plane, and the second cylindrical electrode 19 has a second pair of surfaces 23, 24 arranged symmetrically about the x-z plane. and a fourth pair of surfaces 29, 30 arranged symmetrically about the y-z plane. A pair of tongue-like portions 25 and 26 are provided that protrude in the direction of the screen;
The second cylindrical electrode 19 is the first cylindrical electrode 1
The tongues 25, 26 of the first pair of surfaces 21, 22 are arranged so as to surround the pair of tongues 25, 26 of the first pair of surfaces 21, 22.
The tip portions 25c, 26c of 26 are shaped to protrude with curvature in the screen direction, and the ends 23a, 24 of the second pair of surfaces 23, 24 on the screen side
y of the first pair of surfaces 21, 22 in a portion where a is arch-shaped and concave in the direction of the electron gun, and the pair of tongues 25, 26 are provided.
The difference between the mutual spacing on the axis and the mutual spacing on the x-axis of the fourth pair of surfaces 29 and 30 is the difference between the mutual spacing on the x-axis of the fourth pair of surfaces 29 and 30.
Each of the mutual spacings is set to be within ±20% of the mutual spacing on the y-axis of No. 1 and 22, and the traveling direction of the electron beam deflected in the first direction by the first deflection system The first and second cylindrical electrodes 1
The quadrupole lens composed of 8 and 19 produces an effect of inverting and expanding the deflection, and
A potential is applied to the first and second cylindrical electrodes 18 and 19 so that the electron beam deflected in the second direction by the deflection system is deflected and expanded by the quadrupole lens. The present invention relates to a cathode ray tube characterized in that it is provided with a potential applying means that provides a potential.

[Function] The deflection magnifying electron lens of the above invention has long tongue-like parts 25 and 26, and the distance between the first pair of surfaces 21 and 22 in the tongue-like parts 25 and 26 and the fourth pair of surfaces are Since the difference between the mutual spacing between the surfaces 29 and 30 is set within ±20% with respect to the mutual spacing between the first pair of surfaces 21 and 22, the hyperbolic electric field distribution is close to an ideal quadrupole lens field. is obtained, and the effective area for the aperture diameter of this lens becomes large.
Furthermore, both the concave lens in the x direction and the convex lens in the y direction become stronger, and the deflection sensitivity increases. Therefore, it is possible to provide a CRT with a short overall length.

[First Embodiment] Next, a CRT of an oscilloscope according to a first embodiment of the present invention will be described. CRT shown in Figure 1
includes an electron gun 5 consisting of a cathode 2, a control grid 3 and an anode 4 in an evacuated tube 1. The path of the electron beam emitted from the electron gun 5 includes an aberration correction electron lens 6, first and second quadrupole lenses 7, 8, a vertical deflection system 9, a third quadrupole lens 10, a horizontal deflection system 11, Polarizing magnifying lenses 12 according to the present invention are sequentially arranged. The fluorescent screen 13 is constructed by coating a face plate 14 with a fluorescent substance 15 and providing a conductive layer 16 thereon. A rear acceleration electrode 17 is provided on the inner wall of the funnel portion 1a of the tube body 1, and this rear acceleration electrode 17 is connected to the conductive layer 16 of the fluorescent screen 13.

The deflection magnifying lens 12 according to the present invention consists of first and second cylindrical electrodes 18, 19, the first cylindrical electrode 18 is connected to the ground, and the second cylindrical electrode 1
9 is arranged so as to be slightly surrounded by the rear acceleration electrode 17, and is connected to the rear acceleration electrode 17 by a conductive wire 20.

The cathode 2 of this CRT has a DC voltage of -2kV, for example, and the control grid 3 has a DC voltage of 0.
Low to about 100V, e.g. -2.1kV, anode 4
is 0V (ground potential), aberration correction electronic lens 3
5 has a positive and negative voltage of -50 to +50V, the first, second and third quadrupole lenses 7, 8 and 10 have positive and negative voltages of 0 to 400V, and the rear accelerating electrode 17 has a +14kV, the deflection magnifying electron lens 12 according to the present invention. The first cylindrical electrode 1 of
8 is 0V (ground potential), second cylindrical electrode 19
The same +14 kV as that applied to the rear acceleration electrode 17 is applied to the electrode.

The structure and operation of the CRT other than the deflection magnifying electron lens 12 are the same as those of known CRTs, and the electron beam emitted from the cathode 2 is transmitted to the control grid 3.
After the amount thereof is controlled, it passes through the anode 4 and the aberration correction electronic lens 6 and enters the first quadrupole lens 7. The first quadrupole lens 7 is now horizontally (second
If x is the direction (direction of Dissipate. The second quadrupole lens 8 diverges the electron beam in the xz plane and focuses it in the yz plane. The third quadrupole lens 10 directs the electron beam to
It is focused in the z plane and diverged in the yz plane. The vertical deflection system 9 deflects the beam in the vertical (y) direction in response to the vertical deflection signal (observation signal) supplied thereto, and the horizontal deflection system 11 deflects the beam in the vertical (y) direction in response to the ramp voltage supplied from the sweep circuit. Deflect the beam in the horizontal (x) direction.

The deflection magnifying electron lens 12 according to the invention focuses the electron beam in the yz plane and diverges it in the xz plane. An electron beam that enters this deflection and expansion electron lens 12 with deflection angles in the x and y directions is deflected and expanded in both the x and y directions. The second cylindrical electrode 19, to which the same high voltage as the latter-stage accelerating electrode 17 is applied, accelerates electrons and increases the brightness of the image on the screen. Note that the beam that is vertically deflected and enters the deflection magnifying lens 12 is subjected to a strong focusing action, and its traveling direction is reversed.

Next, the polarizing magnifying lens 12 according to the first embodiment of the present invention will be explained in more detail with reference to FIGS. 2 to 8. As is clear from FIG. 3, the first cylindrical electrode 18 consists of a first pair of surfaces 21, 22 and a second pair of surfaces 23, 24, and is arranged in the
They are each formed symmetrically with respect to the z-plane. The length of the second pair of surfaces 23, 24 is the same as that of the first pair of surfaces 21, 2.
Since it is significantly shorter than 2, the 4 sides 21, 22, 2
A pair of tongue-shaped parts 25 and 26 protrude toward the screen from a cylindrical part surrounded by 3 and 24 and having a substantially rectangular cross-section. This pair of tongues 2
5 and 26 are two edges 25a and 25 that are parallel to each other and extend linearly toward the screen direction.
b, 26a, and 26b. A pair of tongues 2
The tip portions 25c and 26c of 5 and 26 are curved appropriately to correct pattern distortion, and protrude toward the screen with a curvature, as is clear from FIG. The ends 23a and 24a of the second pair of surfaces 23 and 24 on the screen side are also curved to correct pattern distortion, and in this example, they are arched toward the cathode side as is clear from FIG. It's sunken in. The first and second pairs of surfaces 21, 22, 23, 24 obtain a field that approximates an ideal hyperbolic equipotential field, as is clear from FIGS. 2, 3, and 6. for,
It is formed into a quadratic curved surface (hyperbolic surface) that is convex toward the tube axis. Note that the first pair of surfaces 21 and 22 are x
- arranged along the z plane, and the second pair of planes 2
3 and 24 are arranged along the yz plane.

As is clear from FIG. 2, the second cylindrical electrode 19 has a third pair of surfaces 27 and 28 and a fourth pair of surfaces 2.
9 and 30, formed symmetrically with respect to the x-z plane and the y-z plane, respectively, and arranged so as to surround at least one pair of tongues 25 and 26 of the first cylindrical electrode 18. . The third pair of surfaces 27, 28 are x
− arranged along the z plane, and the fourth pair of planes 2
9 and 30 are arranged along the yz plane, and both surfaces are formed into convex quadratic curved surfaces (hyperbolic surfaces) toward the tube axis.

As is clear from FIGS. 4 and 5, the width W ₁ of the first pair of surfaces 21 and 22 is the same as that of the second pair of surfaces 23 and
24, and the width W ₃ of the third pair of surfaces 27, ₂₈ is somewhat narrower than the width W ₄ of the fourth pair of surfaces 29, 30. second pair of surfaces 23,
The width W ₂ of 24 is the width W ₃ of the third pair of surfaces 27 and 28.
approximately equal to. Therefore, the first pair of surfaces 21, 22, ie the pair of tongues 25, 2 on the y-axis in FIG.
6 and the fourth pair of surfaces 2 on the x-axis.
The facing distances of 9 and 30 are approximately equal.

In order to obtain an ideal hyperbolic equipotential field as shown by equipotential lines 31 in FIG. 6, W ₂ = W ₃
It is desirable that W ₂ −0.2W ₂ ≦W ₃ ≦W ₂
If W ₂ and W ₃ are determined to satisfy +0.2W ₂ ,
It has been confirmed that a near-ideal quadrupole lens field can be obtained. Considering the electric discharge between the first cylindrical electrode 18 and the second cylindrical electrode 19, W ₄ −
It is necessary to satisfy W ₂ > 6 mm, W ₃ - W ₁ ≧ 6 mm, and in this example, W ₁ = 16 mm, W ₂ = 20
mm, W ₃ = 24 mm, and W ₄ = 28 mm. Each surface 21, 22, 23, 24, 27, 28, 29,
The curve 30 is determined in such a way that an equipotential field of a rectangular hyperbola x ² −y ² =a ² is obtained in the space of the tongues 25 , 26 .

Tips 25c, 26 of the pair of tongues 25, 26
The shape of c is related to pattern distortion; if it is concave in an arch shape toward the cathode side, the emission line parallel to the x-z plane tends to have barrel distortion, and if it projects in an arch shape toward the screen side, There is a tendency for pink tension distortion.

It is desirable that the ends 23a, 24a of the second pair of surfaces 23, 24 on the screen side are arched and recessed toward the cathode side. These ends 23a, 24a
The shape affects the pattern distortion of emission lines parallel to the yz plane and the polarization straightness in the x and y directions. If the depth of the depressions at the ends 23a and 24a is kept constant, and the curve of the depressions is varied, for example, into a parabola, hyperbola, y ⁿ curve, etc., and the curve at the center of the depression is enlarged, it will become parallel to the y-z plane. The shape of the emission line changes in the barrel direction, and the deflection straightness in the x and y directions increases. Also, the end 2
If the depth of the depression is increased without changing the types of curves 3a and 24a, the emission line parallel to the y-z plane changes in the barrel direction, and the deflection straightness in the x and y directions increases. .

From the center of the tips 25c, 26c of the tongues 25, 26 to the ends 23a, 2 of the second pair of surfaces 23, 24
4a and the linearly extending edges 25a, 25 of the tongues 25, 26.
The length L ₁ of b, 26a, and 26b is related to the strength of the quadrupole lens, and as it becomes longer, both the concave lens effect in the x direction and the convex lens effect in the y direction become stronger, and the deflection sensitivity improves. However, the length L ₁ affects the deflection directness in the y direction, and L ₁
As becomes shorter, the directness of deflection in the y direction increases, and as becomes longer, it contracts, so it must be set to an appropriate value. According to experiments, tongue 2
The second pair of surfaces 23,
If the distance on the y-axis to the center of the ends 23a and 24a of 24 is preferably in the range of W ₂ ±0.2W ₂ ,
It has been confirmed that the deflection straightness in the y direction is improved.

As is clear from the above, in this deflection magnifying lens, if the lengths of the tongues 25, 26 are changed, the deflection straightness in the y direction changes, and the shapes of the tips 25c, 26c of the tongues 25, 26 are changed. If you change it, x-
The shape of the emission line parallel to the z-plane and the polarization straightness in the x direction change, and the end portion 23 of the second pair of surfaces 23 and 24 changes.
By changing the shape of a, 24a, the shape of the bright line parallel to the yz plane changes. Note that the end portions 23a,
Although the deflection straightness in the x direction also changes due to the change in the shape of 24a, this is extremely small compared to the change in the deflection straightness in the x direction due to changes in the tongues 25 and 26. Further, the change in the deflection straightness in the y direction due to the change in the shape of the end portions 23a, 24a is caused by the tongue portion 25,
This can be corrected by changing the length L ₁ of 26. Therefore, if one of the shape of the emission line parallel to the x-z plane and the polarization straightness in the x direction can be changed without significantly affecting the other,
The shapes of the bright lines parallel to the −z plane and the bright lines parallel to the yz plane, and the polarization straightness in the x and y directions can all be optimally set. In the deflection magnifying lens of this example, as W ₂ /W ₁ increases, the deflection straightness in the x direction shrinks without greatly changing the shape of the emission line parallel to the xz plane. The best settings can be achieved by adjusting W ₂ /W ₁ .

The length of the second cylindrical electrode 19, that is, from the tip of the first pair of tongues 25c, 26c to the second cylindrical electrode 19.
As the distance to the screen side edges 27a, 28a of
The shapes of the emission lines parallel to the z-plane both change in the barrel direction, and the deflection straightness in the x and y directions is both extended.
Further, the third pair of surfaces 27 of the second cylindrical electrode 19,
When the screen-side ends 27a and 28a of 28 are arched curves protruding toward the screen, the shapes of the bright lines parallel to the x-z plane and the y-z plane both change in the barrel direction. , and the deflection straightness in the x and y directions is extended. Also, end 27
If a and 28a are made into an arch shape concave toward the cathode, the characteristics will be opposite to those obtained when they are made to protrude toward the screen.

In this example, the voltage of the rear accelerating electrode 17 and the second cylindrical electrode 19 is 14 kV (16 kV with respect to the cathode).
However, as this voltage is increased, the lens effect becomes stronger and the deflection sensitivity in the x and y directions improves. Also, at this time, the deflection straightness in the x direction and the y direction is contracted, and the bright line parallel to the xz plane changes to the barrel direction, and the bright line parallel to the yz plane changes to the pink tension direction.

As shown in FIG. 7, the beam 32 is deflected in the horizontal direction (x direction) and is incident on the first cylindrical electrode 18.
is deflected and expanded in the horizontal direction by a concave lens action determined by the distribution of equipotential lines 33 in the xz plane.

As shown in FIG. 8, the beam 34a is deflected in the vertical direction (y direction) and is incident on the first cylindrical electrode 18.
Or 34b or 34c is the equipotential line 35 on the yz plane
The light is focused by a convex lens action determined by the distribution of light, and its traveling direction is reversed to cross the xz plane, and the light is deflected and expanded. In this deflection magnifying lens, beams 34a, 34b, and 34c intersect the xz plane within the space in which the pair of tongues 25 and 26 face each other. Such a lens effect is caused by the tongue-shaped parts 25, 2.
This can be obtained by increasing the length L ₁ of 6.
If the intersections of the beams 34a, 34b, and 34c with the xz plane are within the spaces in which the tongues 25 and 26 face each other, there is a focusing effect even after the beams intersect, and this focusing effect increases as the amount of deflection in the y direction increases. growing.
Therefore, the effect of reducing the deflection straightness in the y direction is produced. Therefore, by adjusting the lengths of the tongues 25 and 26, the directness of the deflection in the y direction can be improved.

As shown in FIG. 6, the opposing spaces between the tongues 25 and 26 include a pair of tongues 25 and 26 with 0V (2kV to the cathode) and a +14kV (to the cathode)
16kV) and a second pair of surfaces 29, 30. And a pair of tongue-shaped parts 2 on the y-axis
The mutual spacing between the surfaces 5 and 26 is equal to the mutual spacing between the pair of surfaces 29 and 30 on the x-axis. Therefore, an ideal quadrupole lens field is formed as shown by equipotential lines 31. Therefore, the effective utilization area, that is, the pore diameter ratio increases. In this example, the ratio W _y /W ₂ between the lens effective area W _y and W ₂ in the y-axis direction is 0.85, x
The ratio of the axial lens effective line W _x to W ₁ is W _x /W ₁ .
0.5, each of which is significantly larger than a conventional polarizing magnifying lens. Further, the deflection sensitivity in both the x and y directions can be increased to, for example, 2.8 V/cm in the y direction and 2.14 V/cm in the x direction in a CRT having the same overall length as the conventional one. Therefore, the total length of the CRT can be shortened. Note that the distortion of the deflection straightness in the x and y directions is 3% on a 10 x 8 cm tube surface.
less than

[Second Embodiment] Next, a deflection magnifying lens 12b of a second embodiment will be described with reference to FIGS. 9 to 14. However, in FIGS. 9 to 14, parts common to those in FIGS. 1 to 8 are designated by the same reference numerals, and their explanations will be omitted. Polarized magnifying lens 12b shown here
is the deflection magnifying lens 12 shown in FIGS. 1 to 8.
Each surface 21, 22, 2 of each cylindrical electrode 18, 19
3, 24, 27, 28, 29, and 30 are made into flat surfaces. In this way, even if it is a flat surface, the first
Lengths of the tongues 25 and 26 shown in Figures 1 to 13
If L ₁ and the widths W ₁ , W ₂ , W ₃ , and W ₄ of each part are set almost the same as in the first embodiment, a pair of tongue-shaped parts 25 and 26 and a pair of surfaces 29 shown in FIG. A nearly ideal quadrupole lens field can be obtained in the space surrounded by 30, and almost the same effects as in the first embodiment can be obtained.

[Modified example]

The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example.

(a) Third pair of surfaces 27, 2 of second cylindrical electrode 19
The ends 27a, 28a of 8 may be made to protrude toward the screen, or may be depressed toward the cathode. Further, the openings at the ends 27a and 28a may be closed with a plate having an aperture.
If this is closed with a plate with an aperture,
Concave lenses are generated in the y and x directions, producing a pattern distortion correction effect.

(b) It is also applicable to a CRT having a configuration in which some or all of the quadrupole lenses 7, 8, and 10 shown in FIG. 1 are omitted.

(c) The second cylindrical electrode 19 may be configured to apply a voltage different from that applied to the second acceleration electrode 17.

(d) In FIG. 2, the first and second cylindrical electrodes 18, 1
9 was bent into a hyperbolic shape, however, only the vicinity of the central portion intersecting the yz plane and the xz plane may be curved, and the vicinity of the corners may be made flat. Further, the angle of each electrode 18, 19 may be rounded. Further, the cross-sectional shape of each surface may be a curve such as a circle, an ellipse, or a parabola.

(e) It is also applicable to an accumulation tube targeting the screen 13. Therefore, in the present invention, the screen also includes the target.

[Effects of the Invention] As is clear from the above, according to the present invention, it is possible to provide a deflection magnifying lens with a relatively simple configuration and high deflection sensitivity.

[Brief explanation of the drawing]

FIG. 1 shows a CRT according to the first embodiment of the present invention.
2 is a perspective view showing the deflection magnifying lens of the first embodiment, FIG. 3 is a perspective view showing the first cylindrical electrode of FIG. 2, and FIG. 4 is a perspective view of the first cylindrical electrode of FIG. FIG. 5 is a side view of the deflection magnifying lens shown in FIG. 2, FIG. 6 is a sectional view taken along the - line in FIG.
Fig. 7 is a diagram showing the - line cross section and beam trajectory in Fig. 5, Fig. 8 is a diagram showing the - line cross section and beam trajectory in Fig. 4, and Fig. 9 is a diagram showing the deflection magnifying lens of the second embodiment. 10 is a perspective view showing the first cylindrical electrode in FIG. 9, FIG. 11 is a front view of the deflection magnifying lens in FIG. 9, and FIG. 12 is a front view of the deflection magnifying lens in FIG. 9. 13 is a side view of the deflection magnifying lens of FIG. 9, and FIG. 14 is a sectional view taken along the line A--A of FIG. 12. 18...First cylindrical electrode, 19...Second cylindrical electrode, 21, 22...First pair of surfaces, 23, 24
... second pair of surfaces, 25, 26 ... tongue, 2
7, 28...Third pair of faces, 29,30...Fourth
The opposite side of the.

Claims (1)

[Claims] 1. An electron gun, a first deflection system that deflects an electron beam emitted from the electron gun in a first direction, and a second deflection system that deflects the electron beam in a second direction orthogonal to the first direction. a second deflection system that deflects the deflection means;
It comprises at least a screen that impacts the electron beam emitted from the electron gun, and a deflection magnification electron lens disposed between the deflection means and the screen, the deflection magnification electron lens being coaxially arranged. The first cylindrical electrode 18 is configured such that the first direction is the y-axis, the second direction is the x-axis, and the electrons in the non-deflected state are When the traveling direction of the beam is the z-axis, x-z
a first pair of surfaces 21 arranged symmetrically around the surface;
22, and a second symmetrically arranged around the y-z plane.
The second cylindrical electrode 19 has a third pair of surfaces 27, 28 arranged symmetrically about the x-z plane, and a y-z plane.
Fourth pair of surfaces 2 arranged symmetrically around the z-plane
9, 30, a pair of tongue-like portions 25, 26 are provided on the first pair of surfaces 21, 22 and protrude in the screen direction, and the second cylindrical electrode 19 is connected to the first cylindrical electrode 19. The tongues 25 and 2 of the first pair of surfaces 21 and 22 are arranged so as to surround the pair of tongues 25 and 26 of the electrode 18, and the tongues 25 and 2 of the first pair of surfaces 21 and 22
The tips 25c, 26c of the second pair of surfaces 23, 24 on the screen side are arched and recessed in the direction of the electron gun. In the portion where the pair of tongue-shaped portions 25 and 26 are provided, the distance between the first pair of surfaces 21 and 22 on the y-axis and the fourth pair of surfaces 29 and 30 is the same. x
The difference between the mutual spacing on the axis is the first pair of surfaces 21,
Each of the mutual spacings is set to be within ±20% with respect to the mutual spacing on the y-axis of No. 22, and the traveling direction of the electron beam deflected in the first direction by the first deflection system is The quadrupole lens composed of the first and second cylindrical electrodes 18 and 19 causes an action of inverting and expanding the deflection, and the second deflection system causes the deflection to be swung in the second direction. A potential applying means is provided for applying a potential to the first and second cylindrical electrodes 18 and 19 so as to cause the electron beam to be deflected and expanded by the quadrupole lens. cathode ray tube.