JPS61118948A - Image pickup tube - Google Patents

Abstract

PURPOSE:To prevent entrance of impurity into a tube without using an indium ring by chamfering the end faces of a glass bulb and a front glass plate facing to each other and filling nonconductive adhesive or low temperature fused frit glass for sealing in the chamfered portions. CONSTITUTION:A conductive coating 2 constituting an electrode is provided on the inner peripheral surface of a cylindrical glass bulb 1, and a target electrode composed of a transparent conductive coating 5 and a photoconductive coating 6 is formed on a front glass plate 4 sealed air-tightly with one of the opening end face of the bulb 1. Inclined surfaces 7,8 are formed respectively on the end faces of the bulb 1 and glass plate 4 facing to each other by chambering. Low melting point frit glass or nonconductive adhesive forming an adhesive layer 3 is filled in these inclined surfaces 7,8. Furthermore, the conductive coating 5 is led out of the tube by a belt-shaped conductive vapor- deposited coating 9 between the glass plate 2 and bulb 1. Thus, impurity can be prevented to enter into the tube without using an indium ring.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a front glass plate hermetically sealed to one open end surface of a glass bulb housing an electron gun, and a transparent conductive film and a transparent conductive film are coated on the inner surface of the front glass plate. The present invention relates to an image pickup tube provided with a target electrode made of a photoconductive film.

2. Description of the Related Art In general, in an image pickup tube equipped with a photoconductive film type target electrode, a front glass plate is hermetically sealed to one open end surface of a cylindrical glass bulb housing an electron gun via an indium ring. A terminal (target electrode terminal) of a transparent conductive film attached to the inner surface of the front glass plate is led out of the tube through the indium ring. With this configuration, the sealing can be achieved by cold pressure bonding using the indium ring, so the transparent conductive film and photoconductive film attached in advance to the front glass plate do not need to be exposed to high temperatures during sealing. There are advantages.

Recently, as image pickup tubes have become smaller and more sophisticated, it has been desired to provide image pickup tubes with particularly high S/N characteristics. To solve this problem, various measures have been proposed to reduce the output-side capacitance.
If a known output terminal structure is adopted in which a small hole of φ is drilled and the target electrode terminal is led out of the tube through a conductive material filled in this small hole, not only will the number of manufacturing steps increase, but it will also require burying the conductive material. The front glass plate is likely to be damaged during the process, resulting in poor yield. In addition, there is a problem that not only is the airtightness easily broken near the small hole, but also that stray capacitance between the indium ring, the hard metal ring surrounding it, and the shield of the outer coil groove adds to the output capacitance. There is a point.

Problems to be Solved by the Invention Therefore, it is an object of the present invention to provide a high-S The object of the present invention is to provide an image pickup tube with /N characteristics.

Means for Solving the Problems According to the image pickup tube of the present invention, the opposite end surfaces of the glass bulb and the front glass plate are chamfered, and a non-conductive adhesive or a low melting point adhesive for sealing is applied to the chamfered portions. Fill with fritted glass.

Function: With this structure, it is possible to form a sealing part relatively easily without using an indium ring, and not only the transparent conductive film terminal which is the target electrode terminal but also other electrode terminals can be formed in the sealing part. This makes it possible to lead out the tube to the outside of the tube through the tube, making it possible to obtain an image pickup tube with low output capacitance and high S/N characteristics.

Embodiments Next, the image pickup tube of the present invention will be explained in more detail together with embodiments shown in the drawings. Figure 1 and its II-II'
In FIG. 2 showing a cross section, a cylindrical glass bulb 1 has a conductive film 2 constituting an electrode on its inner peripheral surface, and is hermetically sealed to one open end surface of the glass bulb 1 with a sealant layer 3. The front glass plate 4 has a target electrode made of a transparent conductive film 5 and a photoconductive film 6 on its rectangular inner surface area.

However, the opposing end surfaces of the glass bulb 1 and the front glass plate 4 each have an inclined surface 7°8 formed by chamfering, and a low melting point frit glass or non-conductive adhesive is used to form the sealing agent layer 3. is filled in the beveled portion. The width of the face of the plus pargoo is T/3 or more, where T is the thickness of the glass bulb 1. Moreover, the transparent conductive film 6 is pulled out to the outside of the tube through the space between the front glass plate 4 and the sealing agent layer 3, and has a width of 0.5 to 2 m.
It is formed so as to partially overlap the conductive band-shaped vapor deposited film 9 of m, and the outer portion 9N of the vapor deposited film 9 made of chromium or the like is covered with a layer of conductive paint to serve as a target electrode terminal.

The mesh electrode 1o has its peripheral edge held between the first and second metal rings 11 and 12, and the tips of the many claws 13 extending from the first metal ring 11 abut against the end surface of the glass bulb 1. , is covered with a sealant layer 3. In this way, the mesh electrode 1o is supported and fixed so as to face the photoconductive film 6, and another conductive band-shaped vapor deposited film 14 is attached to the opening edge of the glass bulb 1, which communicates from the inside of the tube to the outside of the tube. , a claw 13 is attached to this vapor-deposited film 14.
By contacting the tips of the two, the extratubular portion 14a of the vapor deposited film 14 serves as a mesh electrode terminal. Additionally, there is a third tube at the opening edge of the glass bulb 1 that communicates from the inside of the tube to the outside of the tube.
An electrically conductive band-shaped vapor deposited film 15 is attached, the inner part of the vapor deposited film 15 overlaps the conductive film 2, and the outer part 16+a of the vapor deposited film 15 serves as a terminal for the electrode formed by the electrically conductive film 2. Note that in the color image pickup tube, a color filter and a transparent glass layer for filter protection are provided between the front glass plate 4 and the transparent conductive film 5.

The sealing agent layer 3 is made of low melting point frit glass or a highly heat resistant non-conductive adhesive such as epoxy or polyimide adhesive. Further, the photoconductive film 6 is made of Zn Ss + (Znx
It is made of Cd1-x Te)z (In2Te5) 1z-based material with high heat resistance. The frit glass is supplied by kneading it into a paste together with a vehicle and applying it between the abutting surfaces of the glass bulb 1 and the front glass plate 4. After drying, the frit glass is heated at 300 to 400'C.
preheated to a temperature of After that, heating at a temperature of 400 to 600°C for several minutes forms an airtight seal. However, if an inert gas such as neon or argon is passed through the pulp during this sealing process, the target electrode can be protected from high temperatures and is therefore safe.

When using an epoxy-based adhesive as the material for the sealing agent layer 3, it is best to use a thermosetting type, especially a solvent-free type with a curing temperature of about 80°C or higher, such as Nippon Aple Stick. Aple Bond 789-4 sold by Co., Ltd.
．． 843-4 (trade name) can be used. When using a room temperature curing type, it is necessary to leave it at room temperature for 24 hours or more to cure, but in the case of a heat curing type as mentioned above,
It may be heated for 15 to 30 minutes at a temperature of 0 to 150°C. In addition, when using polyimide adhesive, 20
A good hermetic seal can be formed by heating for several minutes at a temperature of 0 to 30 o'C1. In these cases as well, it is preferable to circulate an inert gas through the glass bulb during the sealing process.

Regardless of which adhesive is used, it is sufficient to butt the glass bulb 1 and the front glass plate 4 together directly or through the claws 13, and apply the adhesive around them.

Effects of the Invention Since the present invention is constructed as described above, the target electrode terminal can be led out of the tube without making a small hole in the front glass plate or using an indium ring. In addition, not only is it easy to supply the sealant, but there is also the advantage that there is almost no risk of the sealant or impurities such as gas generated from the sealant entering the inside of the tube, and it has high S/N characteristics. It becomes possible to manufacture image pickup tubes with a high yield.

[Brief explanation of the drawing]

FIG. 1 is a partially broken front view of an image pickup tube embodying the present invention, and FIG. 2 is a sectional view taken along line nn' in FIG. 1...Glass bulb, 3...Sealing agent layer,
4...Front glass plate, 5...Transparent conductive film, 7, 8...Beveled inclined surface.

Claims (1)

[Claims] An image pickup tube comprising a front glass plate hermetically sealed to one open end surface of a cylindrical glass bulb housing an electron gun, and a target electrode made of a transparent conductive film and a photoconductive film attached to the inner surface of the front glass plate. , wherein opposing end surfaces of the glass bulb and the front glass plate are chamfered, and the chamfered portions are filled with a non-conductive adhesive or low melting point frit glass for the sealing. image pickup tube.