JPH019092Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention has a structure in which an electrode extraction rod is provided on the face plate to improve performance such as the S/N ratio or to extract signals, and the signal is extracted from this electrode extraction rod. The present invention relates to an image pickup tube.

[Technical background of the invention]

In some image pickup tubes, a metal film is formed on the inner wall of the glass envelope by vapor deposition or the like, and this is used as a deflection or focusing electrode. However, in this case, the lead wire of the mesh electrode, which is essential for forming a uniform deceleration electric field toward the target surface, cannot be disposed inside the envelope. For this reason, it is necessary to be able to immediately supply the voltage to the mesh electrode from the outside at the end of the envelope.

Therefore, a conventional image pickup tube of, for example, an electromagnetic focusing type or an electrostatic deflection type is constructed as shown in FIG. A deflection electrode 3 having a meandering pattern for deflecting the electron beam emitted from the electron gun 2 is formed on the inner surface of the glass envelope 1. The deflection electrode 3 is formed by attaching a metal such as Cr to the inner surface of the glass envelope 1 by vapor deposition, and then processing it into a desired electrode pattern shape by, for example, laser trimming. Furthermore, a cylindrical insulating envelope 5 is sealed to the open end of the glass envelope 1 via a mesh retaining ring 4. A face plate 6 is sealed to the open end of the insulating envelope 5, and a transparent signal electrode 7 and a target (photoconductive film) are formed on the inner surface of the face plate 6.
8 are sequentially formed, and a signal extraction rod 9 is buried so as to be connected to the transparent signal electrode 7. A mesh electrode ring 10 is fixed to the mesh holding ring 4, and a mesh electrode 11 is attached to the mesh electrode ring 10 in parallel to the target 8.

In the figure, numerals 12, 13, and 14 are sealing materials, which are generally made of soft metal such as In or low melting point glass such as fritted glass. Further, 15 is a mesh electrode signal extraction ring, and 16 is a guide ring when sealing the face plate.

[Problems with background technology]

First of all, the conventional image pickup tube described above is complicated to assemble, has many parts, and is therefore expensive. Furthermore, since there are multiple locations for the envelope, it is difficult to accurately define the distance between the target 8 and the mesh electrode 11, which is a particularly important dimension, due to deformation of the sealing material or variations in the thickness of the envelope. There is also a mesh electrode 1 for the target 8.
1 in parallel across the entire surface, and therefore, it was not possible to obtain good reproducibility of the image pickup tube characteristics. Also, mesh electrode 1
Since the inner wall of the surrounding air 1 at the outer periphery of the mesh electrode 1 is exposed as it is, this wall surface may be charged with stray electrons, or the electric field distribution may be distorted due to the inclination of the mesh electrode, resulting in deterioration of the shedding characteristics. .

[Purpose of invention]

The purpose of this invention is to provide an image pickup tube that eliminates the following disadvantages, is easy to assemble, can accurately define the distance between the target and the mesh electrode, and has significantly improved characteristics. be.

[Summary of the idea]

In this invention, a ring-shaped electrode film is formed on the inner surface of the envelope around the mesh electrode adjacent to the upper end of the deflection electrode in a meandering pattern, and this electrode film is electrically short-circuited to the mesh electrode. A flange portion having a notch is provided on the mesh holding ring that supports the mesh electrode, and this flange portion is clamped and fixed between the open end surface of the glass envelope and the face plate using a sealing material, and the envelope is inserted through the notch. This is an image pickup tube in which the material and the electrode film on the inner surface of the glass envelope are electrically short-circuited.

[Example of idea]

Taking the electromagnetic focusing and electrostatic deflection type as an example, the image pickup tube of this invention is constructed as shown in Figures 2a, b to 4, and Figure 3 shows the main parts of Figure 2a. The enlarged view of FIG. 4 shows the dimensional relationships of the mesh electrode assembly.

That is, a face plate 19 is sealed to the open end of the bottomed cylindrical glass envelope 17 with a sealing material 18 made of a soft metal such as In. A guide ring 20 is fitted on the outside of the sealing material 18. This guide ring 20 is a member that serves as a guide during sealing, and can be made of a conductor such as metal and brought into contact with the sealing material 18 after sealing to serve as a mesh electrode signal extraction piece. Furthermore, on the inner surface of the face plate 19,
Transparent signal electrode 21, target (photoconductive film) 22
are sequentially formed, and the signal extraction rods 23 are buried so as to be connected to the transparent signal electrodes 21. Note that the sealing material 18 is not in contact with the transparent signal electrode 21. Further, an electron gun 27 is disposed on the bottom side of the glass envelope 17, and deflection electrodes 28, 28 in a meandering pattern are provided on the inner surface of the side wall for deflecting the electron beam emitted from the electron gun 27 . ... are formed by vapor deposition or the like, and a ring-shaped electrode film 29 is formed near the opening end by vapor deposition or the like. This electrode film 29 is provided so as to surround the mesh electrode structure in order to eliminate the influence of electric charges generated on the inner surface of the glass envelope 17, and is separated and insulated from the deflection electrode 28 by a linear portion 28a. has been done. Since the electrode film 29 is formed on the inner surface of the glass envelope 17 by vapor deposition or the like,
It is a ring-shaped electrode with high precision and no deformation. As described later, by keeping the electrode film 29 at the same potential as the mesh electrode,
A highly accurate correction electric field can be formed.

Furthermore, a mesh electrode 24 is disposed within the glass envelope 17 facing the target 22,
This mesh electrode 24 is connected to a mesh electrode ring 25.
and one end of the mesh retaining ring 26, and the three parts are joined together by electric welding.
The other end of the mesh holding ring 26 is formed with a flange portion 26a that is slightly larger than the inner diameter of the glass envelope 17, and this flange portion 26a is provided with a plurality of notches 30, as is clear from FIG. There is. Such a flange portion 26a is brought into contact with the open end surface of the glass envelope 17, and the sealing material 18 is
and the opening end face. The sealing material 18 enters the inside of the glass envelope 17 through the notch 30 provided in the flange portion 26a, and is electrically short-circuited to the electrode film 29. In this case, there is no noise generated by other contact methods, such as those using metal pieces, and an extremely stable electrical contact can be obtained even against vibration shock.

By the way, the thickness t _R of the flange portion 26a of the mesh retaining ring 26 must be strong enough to withstand the vibrational impact exerted on the image pickup tube, since it is clamped and fixed to the glass envelope 17, the sealing material 18, and the face plate 19. It goes without saying that it is better to make it as thick as possible to avoid this. However, as is clear from the sealing example shown in FIG. 3, for the thickness t _g of the glass envelope 17,
If the thickness t _R of the flange portion 26a is very thick, problems will occur. That is, when sealing is performed using the sealing material 18 made of a soft metal such as In, the sealing material 18
is pressurized and moves along the open end surface of the glass envelope 17 and further moves to the upper surface of the flange portion 26a of the mesh retaining ring 26, so that the mesh retaining ring 26 is pressed against the open end surface of the glass envelope 17. becomes incomplete. Further, if the sealing material 18 is present on the flange portion 26a from the beginning before sealing, the movement of the sealing material 18 will be incomplete even if pressure is applied during sealing. Since the clean sealing material surface generated by the movement cannot adhere to the optically polished open end surface of the glass envelope 17, sufficient sealing is required to maintain a vacuum inside the glass envelope 17. It becomes difficult to stably achieve this function. Furthermore, the maximum diameter D ₁ of the mesh retaining ring 26 is the same as that of the glass envelope 17.
If the maximum diameter D ₁ is made sufficiently larger than the inner diameter D 0, it will be strong against vibration and impact, but if the maximum diameter D ₁ is too large, the same development as above and the optically polished opening end surface of the glass envelope 17 and the sealing material will occur. Since the sealing area with the sealing material 18 is reduced, the reliability of sealing using the sealing material 18 such as a soft metal is reduced.

As a result of various experiments taking the above contents into consideration, we found that the thickness is in the range of 0.06t _R /t _g 0.4, and each diameter is in the range of 0.1 mmD ₁ to D ₀ 0.8 mm in terms of vibration and shock resistance and sealing. It was found that the wear resistance was excellent due to the reliability of the wear.

In addition, in order to further improve assembly accuracy and facilitate assembly, the maximum diameter D _IM (in FIG. 4, D ₂ or
If D ₃ ) is 0.05 mm smaller than the inner diameter D ₀ of the glass envelope 17 and satisfies the conditions of D ₀ /D _IM 1.01, it is acceptable in terms of electrical characteristics such as image distortion and uniformity of resolution of the image pickup tube. It was also found that there were no problems due to the effects of thermal deformation during the image pickup tube manufacturing process.

[Effect of idea]

According to this idea, assembly work is very easy,
Therefore, an inexpensive imaging tube can be provided. Furthermore, according to this invention, it is easy to accurately define the distance between the target 22 and the mesh electrode 24, and furthermore, since the mesh electrode is short-circuited to the same potential as the electrode film 29 formed around it, the target Since a parallel electric field between the mesh electrode 22 and the mesh electrode 24 can be easily realized and the inner surface of the envelope is not charged, an image pickup tube with good characteristics can be manufactured with good reproducibility.

In addition, with this invention, the thickness of the sealing material 18 can be freely selected, so if the sealing pressure is kept constant, the face plate 19
In other words, it is easy to maintain a constant distance between the target 22 and the mesh electrode 24, and the parallelism can also be maintained. Further, by utilizing the fit between the inner diameter of the glass envelope 17 and the mesh electrode 24, the assembly accuracy is further improved. Furthermore, since the size of the mesh electrode 24 can be maximized only by being limited by the inner surface of the glass envelope 17, the effective area of the target 22 can be increased, and image distortion within the effective area can be minimized. There is.

Incidentally, FIGS. 5 and 6 show a modification of this invention, and the same effects as in the above embodiment can be obtained.

That is, in FIG. 5, a mesh holding ring 31 made of an annular flat plate is used, and the mesh electrode 24 is held between this mesh holding ring 31 and the mesh electrode ring 25. In this case, a metallic annular part may be interposed between the mesh holding ring 31 and the mesh electrode 24 and welded therebetween.

Also, in FIG. 6, the envelope is composed of a glass envelope 17 and an insulating envelope 32, as in FIG.
The same mesh holding ring 26 as in the figure) is clamped and fixed.

Furthermore, although the above embodiment is an example in which it is applied to mesh extraction from an electromagnetic focusing and electrostatic deflection type image pickup tube, this invention is not limited to this type of image pickup tube, and the invention is applicable to mesh extraction by providing an electrode extraction rod on the face plate. The present invention can be applied to other types of image pickup tubes as long as the electrodes are taken out from the side of the glass envelope.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional electromagnetic focusing and electrostatic deflection type image pickup tube with an electrode extraction rod on the face plate;
Figure a is a sectional view showing an example of applying this invention to an electromagnetic focusing and electrostatic deflection type image pickup tube, Figure 2 b is a developed view showing the electrode pattern on the inner surface of the envelope, and Figure 3. 2 is an enlarged sectional view of the main part of FIG. 2, FIG. 4 is a sectional view showing the dimensional relationship of the mesh electrode assembly parts in FIG. 2, and FIGS. 5 and 6 are variations of this invention. FIG. 17...Glass envelope, 18...Sealing material, 19
... Face plate, 20 ... Guide ring, 21 ... Transparent signal electrode, 22 ... Target, 23 ... Signal extraction rod, 24 ... Mesh electrode, 25 ... Mesh electrode ring, 26 ... Mesh holding ring, 2
6a...Flange part, 27 ...Electron gun, 28...
Deflection electrode, 29... Electrode film, 30... Notch.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A face plate is sealed with a sealing material to the open end of a glass envelope in which an electron gun is provided and a meandering pattern deflection electrode is formed on the inner surface. In an image pickup tube in which a guide ring is fitted and a mesh electrode is attached to the mesh electrode ring, the mesh electrode is arranged opposite to a target on the inner surface of the face plate, and the mesh electrode ring is fixed in contact with the opening end surface of the glass envelope. An image pickup tube characterized in that an electrode film is formed on the inner surface of the envelope around the envelope and is electrically separated from the deflection electrode, and the electrode film and the mesh electrode ring are electrically short-circuited. (2) The mesh electrode ring has a flange portion having a notch in part, and this flange portion abuts the open end surface of the glass envelope, and the open end surface and the sealing material The mesh retaining ring is clamped and fixed, and the sealing material contacts an electrode film provided on the inner surface of the glass envelope through the notch, so that the electrode film and the mesh retaining ring are electrically short-circuited. An image pickup tube according to claim 1 of the utility model registration claim.