JPS5812977B2 - image can - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image tube incorporating a secondary electron multiplier plate (microchannel plate).

Conventionally, a proximity image tube with a built-in secondary electron multiplier (
The proximity tube (proximity tube) is constructed as shown in FIG.

That is, from a glass or fiber optics plate having an input window 2 having a photocathode 1 on its inner surface, a secondary electron multiplier plate 3, and an output fluorescent screen 4 having a metal back on its inner surface. Output windows 5 are sequentially arranged coaxially at predetermined intervals,
It is vacuum-sealed by an outer casing 6 consisting of a metal ring and a ceramic ring.

In this case, the distance between the photocathode 1 and the secondary electron multiplier 3 is, for example, 0.2 mm, and the distance between the secondary electron multiplier 3 and the output phosphor screen 4 is 0.2 mm.
The distance between the two is, for example, about 1 mm.

Further, the secondary electron multiplier plate 3 is configured as shown in FIG.
For example, both end surfaces of a substrate 7 made of high lead-containing glass are coated with conductive material to form an input surface 8 and an output surface 9, respectively.

A large number of channels 10, which are fine holes, are bored in the substrate 7, and the inner surface of the channels 10 is finished smoothly and is surface-treated to obtain a high secondary electron emission ratio. .

In addition, it is finished to be semi-conductive, and by applying a voltage to both end surfaces (input surface 8, output surface 9) of the substrate 7, a uniform accelerating electric field is created in the space inside the channel 10 in the axial direction of the channel 10. is formed.

When such an image tube is in operation, the input surface 8 of the secondary electron multiplier 3 has a voltage of +30 0V with respect to the photocathode 1.
is applied to the output surface 9, and + to the input surface 8 is applied to the output surface 9.
A voltage of around 1000v is applied.

Further, a high voltage of 5 KV, for example, is applied to the output surface 9 of the secondary electron multiplier 3 to the output fluorescent light source 4.

When the light beam 11 enters the input window 2, a light image is formed on the photocathode 1, and photoelectrons are emitted from the photocathode 1 depending on the strength of the light depending on the location.

These photoelectrons are accelerated by the electric field and rush into the channel 10 of the secondary electron multiplier plate 3.

The photoelectrons entering the channel 10 emit a large number of secondary electrons each time they collide with the wall surface, and as they move away from the entrance, the electron density increases and reaches the exit.

This multiplied electron flow is accelerated and focused by a so-called proximity focusing method, and is caused to collide with the output phosphor screen 4 to emit light, producing a bright image.

In this way, an optical image that is multiplied tens of thousands of times relative to the incident light is obtained.

By the way, in conventional electron tubes, it was sufficient space to incorporate pulse or current-carrying getters, but with proximity tubes, it was difficult to incorporate these getters in terms of space, and channel image inte... In an electron tube such as a Siphire, the electron density is high and a high electric field is applied between the tube and the output surface of the secondary electron multiplier 3, so the probability of ion generation is very high.

Furthermore, since the phosphor screen is bombarded with a large amount of electrons, a large amount of gas is generated, so deterioration of the vacuum inside the tube is an unavoidable problem.

Therefore, there are disadvantages such as rapid deterioration of characteristics and extremely short service life.

This invention was made in view of the above circumstances, and provides a proximity type image tube (proximity tube) that has stable characteristics and a long life by adsorbing the released gas inside the tube and improving the degree of vacuum. The purpose is to

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

This invention improves the secondary electron multiplier plate in order to eliminate the above-mentioned conventional drawbacks.The secondary electron multiplier plate built into the image tube of the present invention is constructed as shown in FIG. There is.

That is, the same parts as in the conventional example (FIGS. 1 and 2) are denoted by the same reference numerals.The output surface 9 of the secondary electron multiplier plate 3 is coated with a titanium Ti thin film 13.

In this case, in manufacturing, after the metal vapor deposition film that will become the output surface 9 is vapor-deposited on the end surface of the substrate 7, the Ti thin film 13 may be deposited in an overlapping manner.

Note that the Ti thin film 13 is coated only on the output surface 9, and the inside of the channel 10 is not coated.

In addition, 14 in the figure is a metal back. The image tube of the present invention has the same structure as the conventional example (FIGS. 1 and 2) except that the output surface 9 is coated with the Ti thin film 13 as described above.
Detailed explanation will be omitted.

The image tube of the present invention is constructed as described above and shown in the drawings, and the output surface 9 of the secondary electron multiplier plate 3 is covered with the Ti thin film 13, so that the generated ions are transferred to the output surface 9 and the output phosphor screen 4. The electric field applied between the Ti thin film 1
I'm drawn to 3.

Then, Ti is blown off by colliding with the Ti thin film 13 with high energy, and at this time, released gas inside the tube is adsorbed, improving the degree of vacuum.

As a result, the image tube has stable characteristics and a long life.

Note that Ti is sputtered due to ion collision,
Although some of the Ti may adhere to the metal back surface of the phosphor screen, since Ti belongs to a metal category that has relatively good electron transparency, it will not adversely affect the brightness of the output phosphor screen.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional image tube and a conventional image tube used to explain the present invention, FIG. 2 is a cross-sectional view showing an enlarged secondary electron multiplier in a conventional image tube, and FIG. FIG. 2 is a sectional view showing a main part (near a secondary electron multiplier plate) of an image tube according to an embodiment of the present invention. 3... Secondary electron multiplier plate, 9... Output surface, 13... Ti thin film.

Claims (1)

[Claims] 1. An image tube incorporating a secondary electron multiplier, characterized in that the output surface of the secondary electron multiplier is coated with a Ti thin film.