JPS61121245A - Image pickup tube - Google Patents

Abstract

PURPOSE:To easily form a good sealed layer by sealing a front glass plate providing a transparent conductive film and target electrode at the aperture end of glass bulb for sealing an electron gun with a conductive bonding agent of epoxy resin system. CONSTITUTION:On the occasion of sealing the one aperture end of cylindrical glass bulb 1 sealing an electron gun an image pickup tube with a front glass plate 3a providing, at its internal surface, a target electrode 7 consisting of a color filter 4or color decomposition, a transparent glass layer 5 for filter protection, a transparent conductive film 6 and a a photo conductive film, such sealing agent layer 2 is formed with a conductive bonding agent of the thermal setting type epoxy resin system and a part of it is stacked on the extending portion of the transparent conductive film 6. Therefore, the good sealing part can be formed easily without using an indium ring or metal ring and the image pickup tube having high S/N characteristic with small output electrostatic capacitance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a cylindrical glass bulb that encloses an electron gun, in which a front glass plate is hermetically sealed to one open end surface of the glass bulb, and a transparent plate is attached to 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 conductive film and 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 that encloses 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, not only can the sealing be achieved in a short time by cold pressure bonding using the indium ring, but also the transparent conductive film and photoconductive film attached in advance to the front glass plate can be exposed to high temperatures during sealing. It has the advantage of not having to be exposed. However, on the other hand, the melting point of indium is as low as 167° C., so there is a problem in that it is not possible to heat the vicinity of the photoconductive film to a high temperature to discharge the occluded gas.

Furthermore, since indium is inferior in moisture resistance and acid resistance, there is also the problem that it is difficult to maintain high sealing strength over a long period of time. Furthermore, as disclosed in Japanese Patent Publication No. 35-11358, etc., it became essential to surround the outer peripheral surface of the indium ring with a hard metal ring, which became a factor that prevented the reduction of output capacitance. . Note that if the target electrode terminal protrudes outside the tube due to the metal ring, the stray capacitance and output capacitance between it and the coil structure shield outside the tube will increase, resulting in a decrease in the S/N of the image pickup tube. Become.

Problems to be Solved by the Invention Therefore, an object of the present invention is to provide an image pickup tube with high S/N characteristics in which a good sealing part can be easily formed without using an indium ring or a metal ring. be.

Means for Solving the Problems According to the image pickup tube of the present invention, the sealant layer provided between the glass bulb and the front glass plate for airtight sealing is formed of an epoxy resin-based conductive adhesive. This will be explained in detail below along with embodiments shown in the drawings.

Embodiment As shown in the drawings, a cylindrical glass bulb 1 for enclosing an electron gun has a front glass plate 3 hermetically sealed on one open end face with a sealing agent layer 2. The plate 3 has a color filler 4 for color separation on its inner surface. A transparent glass layer 5 for protecting the filter is provided with a transparent conductive film 6 and a photoconductive film 7.

However, the sealing agent layer 2 is not made of a thermosetting epoxy resin-based conductive adhesive, and a portion thereof overlaps the extension of the transparent conductive film 6. In this embodiment, the end of the conductive wire 8 serving as the target electrode terminal is electrically conductively bonded to the outer surface of the sealing agent layer 2.

As the thermosetting epoxy resin conductive adhesive forming the sealing agent layer 2, for example, Aple Bond 84-11. sold by Nippon Aple Stick Co., Ltd. MI (trade name) can be used. This adhesive is a solvent-free paste type that uses silver filler.
The content of ions such as and + is 6 ppm or less. At least the surfaces of the glass bulb 1 and the front glass plate 3 to be bonded are mirror-polished in advance, and prior to bonding, they are degreased with trichlorethylene or the like and then cleaned with ethyl alcohol or the like. An appropriate amount of the adhesive is applied to the surface to be adhered, dried, and then heated at a temperature of 160 to 170'C for about 1 to 2 hours to cure. After hardening, keep it in boiling water for about 1 hour or heat it in an oven for 300'
The gas in the adhesive is released by heating it to a temperature below C.

Note that if the sealing agent layer 2 is heated to a temperature exceeding 300'C, there is a risk that even a highly heat-resistant photoconductive film will have an adverse effect on the target electrode. Therefore, the heating temperature must be determined in consideration of the material of the photoconductive film used. Further, it is desirable that the outer diameter of the sealing agent layer 2 substantially match the outer diameter of the glass bulb 1, and the layer thickness of the sealing agent layer 2 depends on the diameter of the glass bulb 1, but is 0.2~ 0.3ff1
It is enough.

Effects of the Invention Since the present invention is constructed as described above, it is possible to form a good sealing part relatively easily without using an indium ring or a metal ring, and a high S/N with small output capacitance can be formed. It becomes possible to provide an image pickup tube with special characteristics.

[Brief explanation of the drawing]

The drawing is a sectional view of a main part of an image pickup tube embodying the present invention. 1...Glass bulb, 2...Sealing agent layer, 3...Front glass plate, 6...Transparent conductive film, 7... - Photoconductive film, 8... Conductor wire. Name of agent: Patent attorney Toshio Nakao and one other person';
! l! ... force glass barrier 2 ... sealing side layer, 8 ... 4 wire

Claims (1)

[Claims] In an image pickup tube, a front glass plate is hermetically sealed to one open end surface of a cylindrical glass bulb that encloses an electron gun, and a target electrode made of a transparent conductive film and a photoconductive film is attached to the inner surface of the front glass plate. An imaging tube characterized in that a sealing agent layer provided between the glass bulb and the front glass plate for sealing is formed of an epoxy resin-based conductive adhesive.