JPS6065436A - Meshless type cathode-ray tube - Google Patents

Abstract

PURPOSE:To simplify structure and facilitate manufacture by using a flat cylindrical electrode as an electron lens, providing first to fourth surfaces in this cylindrical electrode so that the cross-sectional shape can be nearly rectangular, aligning the center of the cross section to an axis, and providing a means that applies potential to the cylindrical electrode and a rear-stage electrode. CONSTITUTION:An electron lens 11 is comprised with one cylindrical electrode 17 and is arranged so that the electric field of a rear-stage acceleration electrode 12 can actuate the end of the target 13 side, then is comprised so that the actuation of the electron lens can be obtained using the electric field of the rear- stage acceleration electrode 12. This cylindrical electrode 17 is formed in a flat cross-sectional rectangular box shape with first to fourth surfaces 18 to 21. The cylindrical electrode 17 is arranged on an axis so that a pair of cross-sectional rectangular short sides can be aligned in the vertical direction. The target side end 22 of the first and third surfaces 18 and 20 opposed to the cylindrical electrode is formed in a protruded shape, such as a circle or an ellipse and the target side end 23 of the opposed second and fourth surfaces 19 and 21 is formed almost in a hanging bell shape and is depressed in the electron gun direction.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a cathode ray tube (CRT) for use in oscilloscopes, storage scopes, etc., and more particularly relates to a meshless cathode ray tube having a structure in which mesh electrodes are removed. .

Prior Art A conventional post-acceleration cathode ray tube deflects the electron beam emitted from an electron gun vertically or horizontally, and then uses a post-acceleration electric field generated by a flat or curved mesh and a post-acceleration electrode on the inner wall of the bulb. The acceleration is arranged to obtain a spot of increased brightness on the fluorescent screen. However, this type of cathode ray tube has the disadvantage that the mesh deteriorates the spot resolution and electron gun efficiency, and that secondary electrons hitting the mesh cause halation on the screen surface. In order to solve this type of drawback, a cathode ray tube that does not use a mesh is disclosed in Japanese Patent Publication No. 44-31613, which has a structure of two quadrupole lenses and a hemispherical electrode and eliminates the mesh. However, this type of cathode ray tube has the disadvantage that the deflection angle is large, causing blurring at the edges of the screen surface and poor spot uniformity.Furthermore, it requires two electrodes to correct pattern distortion. The disadvantage was that it required additional placement.

Furthermore, Japanese Patent Application Laid-Open No. 53-87161 discloses a meshless cathode ray tube in which two cylindrical electrode members are arranged to mesh with each other and constitute a quadrupole lens. However, in this type of cathode ray tube, the shape of the interlocking part is complicated and difficult to manufacture, and a potential difference of 20 kV must be applied between the two cylindrical electrodes to maintain the withstand voltage between the two cylindrical electrodes. Furthermore, a box-shaped scanning magnifying lens disclosed in Japanese Patent Publication No. 57-25942 is known as a cathode ray tube that does not use a mesh.

However, in this type of cathode ray tube, the lens has a total length of 1
Because it is much thicker than the dome mesh method at 0.6 crn, width 6.3 cm, and height 2.5 crn, it has the disadvantage that conventional glass bulbs cannot be used, and when used in post-acceleration cathode ray tubes, it is necessary to Since the exit electrode is electrically connected to the screen potential, it has the disadvantage that it is difficult to maintain voltage resistance with other electrodes.

Further, Japanese Patent Publication No. 58-8543 and Japanese Patent Application Laid-Open No. 55-53858, filed by the applicant of the present invention, disclose a box-shaped lens having a slit. This consists of a lens created based on a box divided into 3 or 2 parts, and a lens created based on a slit on the target side surface of this box, and the interaction between these two lenses creates a display with less vertical blur. This made it possible. However, in the three-part method,
Since the intermediate electrode of the box-shaped lens divided into three parts has a convex or concave shape in both directions of the cathode and the target, there is a drawback that it is difficult to improve the assembly accuracy between each electrode. In addition, in both the 3-split and 2-split systems, it is necessary to surround the first lun with a shield electrode in order to prevent the subsequent accelerating electric field from entering the approximately 1 m gap provided between each electrode for insulation. It was inconvenient. Furthermore, the provision of slits made the configuration complicated.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide a meshless cathode 11M tube that is simple in structure, easy to manufacture, and inexpensive.

Structure of the Invention To achieve the above object, the present invention includes an electron gun and a deflector for deflecting an electron beam emitted from the electron gun in a first direction and a second direction perpendicular to the first direction. at least one back-stage electrode provided after the deflection system, a target for impacting the electron beam emitted from the electron gun, and an electron lens disposed near the back-stage electrode. In the meshless cathode ray tube, the electron lens is composed of a flat cylindrical electrode, and the first cylindrical electrode is arranged such that the cylindrical electrode has a substantially rectangular cross section.
, has second, third, and fourth surfaces, the center of its cross section coincides with the tube axis, the pair of long sides of the rectangle extends in the first direction, and the pair of short sides of the rectangle arranged to extend in the second direction, the ends of the opposing first and third surfaces of the cylindrical electrode on the target side are each formed in a convex shape;
The target-side σ5 ends of the opposing second and fourth surfaces of the cylindrical electrode are each formed in a concave shape, and the relationship between the potential of the cylindrical electrode and the potential of the subsequent electrode produces the following effect; In order to produce an effect of deflecting and enlarging the electron beam swung in the second direction by the deflection system, a potential applying means is provided for applying a potential to the cylindrical electrode and the subsequent electrode. This relates to a meshless cathode ray tube characterized by:

Effects of the Invention According to the above-described invention, the deflection-enlarging electron lens effect is produced by the relationship between the single cylindrical electrode and the subsequent electrode, so the structure becomes extremely simple. Therefore, manufacturing becomes easy and costs can be reduced.

Next, a cathode ray tube (hereinafter referred to as CRT) of an oscilloscope according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

The CRT shown in FIG. 1 has a
Cathode (2), first grid (3) and second grid (
4), a first anode (5), and a second anode (6); an electron gun (7) that deflects the electron beam emitted from the electron gun (7) in a first direction (vertical direction); 1 and a pair of horizontal deflection plates (9) as a second deflection system that deflects the electron beam in a second direction (horizontal direction). , and an electron lens (11) for deflection and magnification, and historically, the outer wall I
Post-acceleration electrode consisting of a four-electroelectric sheath υ provided on the inner surface of ll □
The electron gun (7), the deflection system GO+, the rear acceleration electrode α2, and the target Q31 are known parts, and the cylindrical electron lens a
D is a new part related to the present invention. Note that the target (13) includes the face plate I and the phosphor layer (15).
1 and a conductive layer aQ connected to a rear acceleration electrode a2.

The electronic lens Q11 according to the present invention has one cylindrical electrode (
17) is arranged so that the electric field of the rear accelerating electrode acts on its end on the target side, and is configured to obtain an electron lens effect by utilizing the electric field of the rear accelerating electrode.

In order to operate the CRT configured as described above, for example, -2.5 kV is applied to the cathode (2) and the first grid (3) is applied.
-2600V to -2500V to the second grid (4), OV to the first anode (5), a focus voltage adjusted to about -1800V to the second anode (6), -300V to +
300v, late acceleration tlH (121K 17.5 kV
, 0■ is supplied to the cylindrical electrode (17) of the electron lens (11).

The electron beam emitted from the cathode (2) is the first
The beam amount is controlled by the grid (3), and the beam amount is controlled by the second grid (4).
) and then the second grid (4) and the first and second
It is focused by a unipotential lens composed of anodes (51 and 61) and sent to the deflection system 00. When the electron beam is swung in the first direction (vertical direction) by the deflection system QOI, the progress of this beam is The direction is the electron lens (111
, and the deflection is expanded in the first direction. Further, when the electron beam is deflected in the second direction (horizontal direction) by the deflection system, the electron beam is deflected and expanded in the second direction by the electron lens (Ill).

Figures 2 to 6 show details of the electron lens (11) in Figure 1.
As is clear from the figure, the cylindrical electrode an has the first, second,
3rd and 4th face 081 (11 (2tl (21)
It is formed into a rectangular box shape with a flat cross section. In addition, as shown in FIG.
A pair of long sides of the resulting rectangular cross section are in the second direction (horizontal direction)
, the 20th surface α9 and the fourth surface C opposite thereto
The pair of short sides of the cross-sectional rectangle produced by D are in the first direction (
A cylindrical electrode (171) is arranged on the tube axis so as to coincide with the vertical direction.

Opposing first and third surfaces Q81 (2t
Each end (24) on the target side of ll is formed into a convex shape like a part of a circle, an Okegawa, or a hyperbola as shown in FIGS. 2 and 3, and protrudes in an arch shape toward the target. Each end (23) on the target side of the opposing second and fourth surfaces is formed into a substantially bell-shaped concave shape as shown in FIGS. 2, 4, and 6, and is depressed toward the electron gun. To explain this end (23+) concave pattern in more detail, as is clear from FIG. (A first circular arc (211) with a first radius R1 centered on a point on the center line extending in the direction of
3a) and the fourth surface (centered on a point located closer to the electron gun than the target side end of 2Il) and the second radius R2 from one end of the arc [23a] of ml to the first surface θ81. A second circular arc (23b) drawn as shown in FIG.
It consists of a third circular arc (23c) drawn from the other end to the third surface (2). Note that the second surface a1 is the fourth surface a1.
The face CI! ]).

C with a display screen of 8 crn vertically and 10 crns horizontally
To illustrate the geometric dimensions of the cylindrical electrode αn in RT, the height in the vertical direction, that is, the second and fourth planes (the height of 21J is about 15 m, and the width in the horizontal direction, that is, the first and third planes). (')
Surface (181 (2Q (7) Ii% approximately 36 mm,
The length from the first and third (Jljj (181t2t)) beam entrance ends (241 to the target side ends (two vertices) is approximately 34 mm, and the second and fourth surfaces (191 (211) beam entrance ends The length from the end (25) to the most r-bored point of the target side end 3) is approximately 18.5 + am, and the end (22
1 has a radius of curvature of approximately 39 mm. Furthermore, the radius of curvature loss, R2, of the end (231) shown in FIG. 6 is about 4 van and about 3 van, respectively.
．． 5, and the second arc (z3b) and the third arc (2
The width D1 of the part closest to 3c) is approximately 7.4 mm, and the depth Hl of the first arc (23a) is approximately 5.5 mm.
mtn, f, 2 and h $ 3 (7) Arc (23b
) The depth R2 of the portion (23c) is about 5 mm.

Note that the cylindrical electrode side is made of non-6R stainless steel with a thickness of 0.5 mm.

Next, with reference to FIGS. 7 and 8, the electron lens (fl)
Explain the trajectory of the electron beam at . Now, the cylindrical electrode (17
) for example O■, for example 17.5k for the α force of the rear accelerator electrode.
When V is applied, a high electric field penetrates into the cylindrical electrode (17) based on the latter acceleration electrode (I2), causing the end of the cylindrical electrode (17) on the target side (221 (231, i.e. near the exit The electron lens is constructed in the cross section of the part corresponding to ■--'II in Fig. 3 shown in Fig. 7.
Equipotential lines (26) are distributed so that a convex lens effect occurs. As a result, the electron beam (271 or (281) swung in the first direction (vertical direction) receives a convex lens effect,
Its direction of travel is reversed, deflected and expanded in the first direction, and reaches target 03).

On the other hand, in the cross section of the portion corresponding to the Vnl and -VIIL lines in FIG. 4 shown in FIG. 8, isopotential lines (2) are distributed so that a concave lens effect occurs. As a result, the second
The electron beam (3 [11 or 61) swung in the direction (horizontal direction) does not proceed as shown by the dotted line, but proceeds as shown by the solid line, is deflected and expanded in the second direction, and hits the target α3).
reach.

By the way, when constructing an electron lens using cylindrical electrodes, the most important problems are pattern distortion, polarization expansion, and spot uniformity in the first direction (vertical direction). Regarding pattern distortion, especially the vertical direction on the target (13)
The pattern at the left and right ends of the bright line becomes a problem. just the edge (ha)
If it is approximated by a single concave circle in the target direction, considerable bottle cushion distortion will occur. Therefore, in this case, a pattern distortion correction electrode must be added. In this embodiment, the problem of bottle cushion distortion is solved by making the end (23) into a substantially bell-shaped concave shape. In addition, the optimal deflection straightness in the horizontal direction was determined at the end (231
The condition of the depression and the edge CI! The optimum deflection linearity in the vertical direction is obtained based on the radius of curvature of the cylindrical electrode (17) (approximately 15 mm in this example) and the depth of the end (c) as shown in FIG. was obtained by forming an equipotential forest (26) like this. The problem of spot uniformity in the vertical direction (normally, the vertical width of the spot becomes thicker as it goes from the center to both the upper and lower ends), as is clear from the equipotential line (2G) in Figure 7, which passes along the tube axis. The problem was solved by giving the beam a strong focusing lens effect, and giving the electron beam swung vertically by the deflection system a weak focusing lens effect.

As described above, according to the present embodiment, one cylindrical electrode Q1 is inserted between the deflection system and the target laser (C31), and the second stage acceleration '
[By applying a high electric field due to K-pole a, a deflection and magnification electron lens (111) can be obtained. Therefore, the configuration of the CRT becomes simple and the desired assembly accuracy can be obtained extremely easily. It is also possible to reduce the cost of CRT.

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

(B) As shown in FIG. 9, the cylindrical electrode Q71 may have a flat cross section (approximately rectangular shape close to 6 circles).
First to fourth surfaces (18) substantially the same as in the case of FIG.
-(211 is generated, and the cylindrical electrode (17
Substantially the same effects as 1 can be obtained.

(13) As shown in Figure 10, the first and third surface planting (
20) may be formed to widen toward the target.

Further, the second and fourth surfaces (II C11) may also be widened toward the target.

C) As shown in Figure 11, three sets of quadrupole lenses (4υ (4
It is also applicable to CRTs with 3C44. In this case, the electrodes in the second direction (left and right) with respect to the beam traveling direction of the lens (4I), for example, O~-500cm, are applied to the lens (4I).
For example, apply +500V to the electrodes in the first direction (up and down) of 41).
, Lens (e.g. +500μ for the left and right electrodes of 4), Lens (for example 0 to -500μ for the upper and lower electrodes of 4), Lens (for example -100 to -300μ for the left and right electrodes of 4), Lens (for example For example, O2 is applied to the upper and lower electrodes of the electrode.In this way, the same effect as in the first embodiment can be obtained.

(JJ As shown in Figure 12, a quadrupole lens (44) is added between the vertical deflection plate (8) and the horizontal deflection plate (9), and the left and right electrodes are For example, −100 to −300 μ may be applied to the upper and lower electrodes, and 0 μ, for example, may be applied to the upper and lower electrodes.Even with this configuration, the same effects as in the embodiment can be obtained.

(T) As shown in FIG. 13, the funnel part of the vacuum outer wall fi+ surrounding the Kugt side opening of the cylindrical electrode (171) is made parallel to the tube axis so that the necessary assembly accuracy can be easily obtained. The performance of the CRT may be stabilized.

α・) As shown in FIG. 14, a cylindrical electrode (12a) electrically connected to the latter accelerating electrode α2 provided on the inner surface of the vacuum outer wall (1) is provided, and a cylindrical electrode aη is disposed within the cylindrical electrode (12a). It's okay. In this way, it becomes possible to stably install the cylindrical electrode aD constituting the -electron lens.

Note that the cylindrical electrode (12a) is the latter acceleration electrode (12a) on the wall surface.
It acts in the same way as 2.

(G) In Fig. 6, the approximate bell shape of the end (23) is R1, R
2 is approximated by two circles, but this approximately bell shape may be approximated by a suitable group of quadratic curves (for example, a circle, an ellipse, a hyperbola, etc., or a combination thereof). The same applies to the end (221).

11) An electromagnetic focusing electron gun may be used instead of an electrostatic focusing electron gun. Further, the deflection system may have an electromagnetic deflection configuration.

(■) It goes without saying that there is no problem in correcting Hattern distortion or adding a fine adjustment means.

(J) It is possible to cause an electron lens effect to occur in the cylindrical electrode (In) in relation to the collimation electrode of the storage tube, etc. Therefore, the present invention can also be applied to the storage tube, etc.7.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a CRT according to an embodiment of the present invention;
2 is a perspective view schematically showing the cylindrical electrode of the CRT shown in FIG. 1, FIG. 3 is a plan view of the cylindrical electrode of FIG. 2, and FIG.
Figure 5 is a side view of the cylindrical electrode in Figure 3.
, -V line sectional view, 81S 6 is an enlarged side view of the cylindrical electrode in FIG. 4, FIG. 7 is a sectional view of a portion corresponding to the Vll-Vll line in FIG. 3 showing the beam trajectory, FIG. 8 is a sectional view of a portion corresponding to the Vill-Vllll line in FIG. 4 showing the beam trajectory, FIG. 9 is a sectional view showing a modified cylindrical electrode, and FIG. 10 is a sectional view of a modified cylindrical electrode. A perspective view showing,
FIGS. 11, 12, 13, and 14 are cross-sectional views showing modified CRTs, respectively. (7)...electron gun, (fi+...deflection system, (Ill
...Electron lens, α force...Late acceleration electrode, (I3)
...Target, an...Cylindrical electrode, 08)...
First surface, (19)...Second surface, (20)...Third surface, (2]J...Fourth surface, C21...Kugt side end. Substitute Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 10 Figure 7 Figure 11 Procedural amendment (voluntary) March 12, 1981 Patent application No. 173562 2, Title of the invention Metschleth type cathode diverticulum 3, Relationship with the case of the person making the amendment Applicant 4, attorney fil Amend the scope of the claims as shown in the attached sheet. (2) Letter A No. 9 In the negative 8th line, add the following sentence after J. [Also, in U.S. Pat. An electron lens system using a cylindrical electrode is disclosed, but this lens is effective for focusing a flat ribbon beam onto a leg, and is not a lens for deflection and magnification.'' f3) tJ[4+Itm 10 ji [line 11] “2
．． Correct z, J to "1142". (4) Change “2nd” on page 10, line 12 of the specification to “11th”
Correct to. (5) “−2,5J to 1−” on page 13, line 13 of the specification
Correct to 1.5". (6) l' on page 13, line 14 of the specification - 2600V~
Correct to "-1600V to -1500V" which is -2500VJ. (7) [-1800VJ 1] on page 13, line 15 of the specification
--Correct to 1000Vj. (8) Add the following sentence after ``biased and honest reporting'' on page 20, line 8 of the specification. [Increasing the rear-stage acceleration ratio than before] (9) Correcting Figure 1 of the drawing to the attached drawing. 2. Claims fil An electron gun, a deflection system that deflects an electron beam emitted from the electron gun in a first direction and a second direction perpendicular to the first direction, and A meshless type negative 4M decomposition tube comprising at least one back-stage electrode provided at a back-stage, a target for impacting an electron beam emitted from the electron gun, and an electron lens disposed near the back-stage electrode. In the first aspect, the electron lens is made of a flat cylindrical electrode, and the cylindrical electrode is arranged to have a substantially rectangular cross-section. Second,
the rectangle has third and fourth surfaces, the center of its cross section coincides with the tube axis, the pair of long sides of the rectangle extend in the second direction, and the pair of short sides of the rectangle extend in the first direction. the ends of the opposing first and 30th surfaces of the cylindrical electrode on the target side are each formed in a convex shape, and the opposing second and fourth surfaces of the cylindrical electrode are each formed with a concave end on the target side, and an electron beam deflected in the first direction by the deflection system is applied to the cylindrical electrode according to the relationship between the potential of the cylindrical electrode and the potential of the subsequent electrode. The cylindrical electrode and the rear stage are arranged so as to reverse the traveling direction of the electron beam (fi11) and to cause an action of expanding the electron beam in the second direction by the deflection system. A mesh-less type cathode ray tube is characterized in that it is provided with potential applying means for applying a potential to the electrodes. The meshless cathode ray tube according to claim 1. (3) The meshless cathode ray tube according to claim 1, wherein the cylindrical electrode has a flat, substantially elliptical cross-sectional shape. (4) The meshless cathode ray tube according to claim 1. The mesh-less cathode ray tube according to claim 1 or 2 or the center of claim 3, wherein the first and third blood are formed to diverge toward the target. The meshless cathode ray tube according to claim 1 or 2 or 3 or 4, wherein the surface 4 is formed to widen toward the target. (6) The second and second surfaces (7) The concave shape at the end of the target side of the second and fourth surfaces is a 16-acute shape. is the first point located on the center line of the second and fourth surfaces that is closer to the target than the end of the second and fourth surfaces of 11J and that extends in the tube axis direction. The arc of t1?” and the second and fourth arcs
1111) from the other end of the first circular arc to the second
A mesh-less cathode ray tube according to claim 1 or 6, wherein the cathode ray tube comprises a third circular arc drawn so as to reach the plane of the meshless cathode ray tube. (8) The latter electrode includes an electrode provided on the tube wall and a cylindrical electrode arranged to surround the target-side end of the cylindrical electrode and electrically connected to the electrode provided on the tube wall. Patent pole f1M, which consists of an electrode! Yes.

Claims (1)

[Claims] +11 An electron gun, a deflection system that deflects an electron beam emitted from the electron gun in a first direction and a second direction perpendicular to the first direction, and A meshless cathode ray tube comprising at least one rear electrode provided at a rear stage, a target for impacting an electron beam emitted from the electron gun, and an electron lens disposed near the rear electrode. the electron lens is made of a flat cylindrical electrode, and first, second, and
the rectangle has third and fourth surfaces, the center of its cross section coincides with the tube axis, the pair of long sides of the rectangle extend in the first direction, and the pair of short sides of the rectangle extend in the second direction. The ends of the opposing first and third surfaces of the cylindrical electrode on the target side are each formed in a convex shape, and the opposing second and fourth surfaces of the cylindrical electrode The ends of the surfaces on the target side are each formed in a concave shape, and depending on the relationship between the potential of the cylindrical electrode and the potential of the subsequent electrode, electrons deflected in the first direction by the deflection system are directed to the cylindrical electrode. The cylindrical electrode and the rear-stage electrode are arranged so as to produce an action of reversing the traveling direction of the beam and deflecting and enlarging it, and also producing an action of deflecting and enlarging the electron beam swung in the second direction by the deflection system. A meshless cathode ray tube characterized in that it is provided with means for applying a potential (=J) to the electrode. (2) The cylindrical electrode is formed in a flat box shape. (j) A mesh-less cathode ray tube according to claim 1. (3) A mesh-less cathode ray tube according to claim 1, wherein the cylindrical electrode has a flat, substantially elliptical cross-sectional shape. (4) The meshless type cathode #J! tube according to claim 1, 2, or 3, wherein the first and third surfaces are formed to widen toward the target. 5) The concave shape at the end of the second and fourth surfaces on the target side is approximately hook-shaped.
3. The meshless cathode ray tube according to item 3 or 4. (6) The concave shape at the target-side ends of the second and fourth surfaces is located closer to the target than the target-side ends of the second and fourth surfaces and extends in the tube axis direction.
and the first point centered on a point on the center line of the fourth surface.
A circular arc drawn from one end of the first circular arc to the first surface centered on a point located closer to the electron gun than the target side ends of the second and fourth surfaces. The second arc extends from the other end of the first arc to the second surface, centering on a point that is closer to the electron gun than the end of the second and fourth surfaces on the target side. Claim 1 or 5, respectively, consisting of a drawn third circular arc.
Metschless type cathode ray tube described in section. (7) The latter electrode is arranged so as to surround the electrode provided on the tube wall and the end of the cylindrical electrode on the target side, and is almost electrically connected to the electrode provided on the tube wall. A meshless cathode ray tube according to claim 1 or 2 or 3 or 4 or 5 or 6, which comprises a cylindrical electrode.