JPS62254338A - Microchannel plate and manufacture thereof - Google Patents

Abstract

PURPOSE:To simplify a manufacturing process, by radiating ultraviolet rays to a photosensitive glass base body which is crystallized after being irradiated by the ultraviolet rays through a mask, and forming plural microchannels through a prosess of eliminating the irradiated portion by etching. CONSTITUTION:A plate type photosensitive glass base body 11 made of a material crystallized by ultraviolet rays is diagonally irradiated by the ultraviolet rays 16 through a mask 15, and plural microchannels are formed along its thickness direction by eliminating the irradiated portion by etching. Then, the secondary electron emission faces 23 are formed on the inside face of the microchannels 12 by processes of plating of metal film and oxidation and also, acceleration electrodes 13 are formed on both faces of the base body 11 by a lift off method. And the microchannel plates which work as the secondary electron multiplicator are constituted. Thus, a manufacturing process can be simplified and the product of either a large area or a different shape can be obtained easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a microchannel plate, which is a type of secondary electron multiplier, and a method for manufacturing the same.

(Prior Art) A microchannel plate multiplies secondary electrons using minute pores called microchannels.

Figure 3 shows an image intensification system using a microchannel plate. Photoelectrons 3 emitted from the photocathode 2 excited by the input light 1 are accelerated by one of the photocathode 1 and the microchannel plate 4. After being accelerated by the voltage E1 applied between it and the electrode 6a, it obliquely enters the microchannel 5.

A secondary electron emitting surface is formed on the inner surface of the microchannel 5, and the secondary electrons emitted from this secondary electron emitting surface are transferred to the electrodes 6a on both sides of the microchannel plate 4.
, 6b, and the collisions are repeated within the microchannel 5 as shown in FIG.

The multiplied secondary electrons 7 outputted from the microchannel plate 4 are imaged by the voltage E3 on the fluorescent screen 8, which also serves as an anode, to form a visible image.

Here, in the conventional microchannel plate, the microchannel 5 has an inner diameter of 15 μmφ and a length of ~1.5 yr.
It is made of glass capillary tubes with a diameter of about 100 nm, and is composed of a large number of capillary tubes bundled together. A secondary electron emitting surface on which PbO is deposited is formed on the inner surface of the capillary tube.

To explain the manufacturing process of such a conventional microchannel plate, first, a core is inserted into a glass cylindrical body that becomes a capillary tube, and the core is heated and expanded to form an elongated shape. Next, a large number of these are bundled and fused together, heated and stretched again, fused and integrated, sliced thinly and polished, and then the core portion is removed by etching. Then, PbO is deposited on the inner surface of the capillary tube by heat treatment, and then an acceleration electrode is deposited.

This method not only requires complex steps to form the individual capillary tubes, but also complex steps to integrate them.

Therefore, productivity is poor and costs are high, and if a large area is to be obtained, an extremely large number of capillary tubes must be prepared, which significantly deteriorates productivity.

Furthermore, there is a problem in that it is difficult to create a wide variety of shapes because there are restrictions on how the capillary tubes can be bundled.

(Problems to be Solved by the Invention) As described above, conventional microchannel plates have had problems in that the manufacturing process is complicated and it is difficult to increase the area and diversify the shapes.

The present invention solves the problems of the prior art, and provides a microchannel plate and its manufacturing method that have a simple IT manufacturing process, can easily be made into a large area, and can be made into any shape. With the goal.

[Structure of the Invention] (Means for Solving the Problems) The microchannel plate according to the present invention uses a plate-shaped photosensitive glass as a base, and forms a plurality of microchannels along the thickness direction on the plate-like photosensitive glass. A secondary electron emitting surface is formed on the inner surface of the microchannel formed on the photosensitive glass substrate, and furthermore, acceleration electrodes are provided on both sides of the photosensitive glass substrate so as to partially electrically contact the secondary electron emitting surface. According to the present invention, the microchannel plate having the above structure is manufactured by the following steps. That is, a plate-shaped photosensitive glass substrate made of a material that crystallizes when irradiated with ultraviolet rays is prepared, and the substrate is exposed to ultraviolet rays through a mask having multiple pores, thereby etching the portions irradiated with ultraviolet rays. is removed to form a plurality of microchannels along the thickness direction. After forming secondary electron emitting surfaces on both surfaces of the photosensitive glass substrate and the inner surface of the microchannel, acceleration electrodes are formed on the secondary electron emitting surfaces on both surfaces of the photosensitive glass substrate by a lift-off method.

(Function) Since the microchannel plate according to the present invention has a plurality of microchannels formed on the same photosensitive glass substrate and has an integral structure, during manufacturing, capillary tubes constituting the individual microchannels are formed. There is no need for a process to integrate them, and there is also no need for a process to integrate them. That is, in the manufacturing process of the microchannel plate according to the present invention, a large number of microchannels are simultaneously formed by irradiating the photosensitive glass substrate with ultraviolet rays through a mask and etching away the portions irradiated with the ultraviolet rays. It is also possible to form each microchannel at the same time through processes such as plating and oxidizing a metal film. Furthermore, since the acceleration electrode is formed by a lift-off method, the acceleration electrode material does not adhere to the inner surface of the microchannel and damage the secondary electron emission surface.

(Example) The first factor is a diagram showing an outline of a microchannel plate according to an example of the present invention. As shown in the figure, a microchannel 12 consisting of a large number of pores is formed along the thickness direction of a circular plate-shaped photosensitive glass substrate 11. A secondary electron emitting surface is formed on the inner surface of the microchannel 12, and acceleration electrodes 13 are formed on both surfaces of the photosensitive glass substrate 11 to be in electrical contact with the secondary electron emitting surface.

In the microchannel 12, electrons incident from a direction perpendicular to the photosensitive glass substrate 11 pass through the microchannel 12.
2, so that the generated secondary electrons can collide with the secondary electron emitting surface many times without passing through, and the generated secondary electrons can repeatedly collide with the secondary electron emitting surface many times. It is formed.

The peripheral edges 11a of both sides of the photosensitive glass substrate 11 have a thickness of 1 to several μm.
It protrudes by a height of about m. This requires strict alignment of the microchannels formed in each microchannel plate by forming a gap of several micrometers between them when multiple microchannel plates are stacked. This is to transmit the secondary electrons to the next stage microchannel plate without any interference.

Next, a method for manufacturing a microchannel plate according to the present invention will be explained with reference to FIG.

First, as shown in FIG. 2, a mask 15 made of a metal such as CR or an emulsion having a large number of pores 14 is provided on one surface of a circular plate-shaped photosensitive glass substrate 11. The surface of the photosensitive glass substrate 11 is irradiated with parallel ultraviolet light 1i116 obliquely. The photosensitive glass substrate 11 is a known material made of a material that changes from amorphous to crystalline upon irradiation with ultraviolet rays. Through this step, the ultraviolet irradiated portion of the photosensitive glass substrate 11 where microchannels are to be formed is crystallized.

The photosensitive glass substrate 11 that has been selectively exposed by the irradiation with the ultraviolet rays 16 is chemically etched to remove the ultraviolet irradiated portion, resulting in a diameter of 15 mm as shown in FIG. 2(b).
Pores on the order of μm, that is, microchannels 12 are formed. This microchannel 12 is oblique to the surface of the base 11.

Next, as shown in FIG. 2(C), a ring-shaped mask 17 made of the same material as the mask 15 used in the step of FIG. 2(a) is placed on one surface of the photosensitive glass substrate 11. ,
Parallel ultraviolet rays 18 are irradiated perpendicularly to the surface of the base 11 through this mask 17 . Then, chemical etching is performed in the same manner to remove only the surface layer of the portions exposed to ultraviolet rays. In order to remove only the surface layer of the photosensitive substrate 11 in this manner, the irradiation time of the ultraviolet rays 18 or the etching time may be made shorter than that in the step of forming the microchannels 12.

Similar steps are performed on the opposite side of the base 11 as well. As a result, as shown in FIG. 2(d), the surface of both sides of the photosensitive glass substrate 110 excluding the peripheral edge 11a is removed by a predetermined thickness, thereby obtaining a shape in which the peripheral edge 11a protrudes. .

Next, in order to form a secondary electron emitting surface on the inner surface of the microchannel 12, the photosensitive glass substrate 11 is first degreased to remove organic matter adhering to the surface, and then as shown in FIG.
As shown in the figure, a CLI film 19 is formed on the entire surface of the substrate 11 by electroless plating, and then Pb1l! 20 is formed by electrolytic plating.

Electroless plating of Cu is performed as follows.

After sensitizing the photosensitive glass substrate 11 by immersing it in a 3nCffi2 solution, PdCji! Activate the surface by soaking it in the Z solution. For surface activation, in addition to the substrate 1
1 can also be immersed in a mixed colloidal solution of PbCQ2 and PdCβ2. Next, the substrate 11 is washed with water and then immersed in an electroless plating solution to form a Cu film 19 with a thickness of about several μm. The plating solution used at this time is copper sulfate and formalin.

A mixed solution of sodium hydroxide, sodium carbonate, nickel chloride, Rochelle's salt, EDTA, triethanolamine, thiourea, and 2-mercaptobenzothianol (however, the six components after nickel chloride may not be included) ), and its composition shall be selected appropriately.

On the other hand, electrolytic plating of Pb1120 is performed as follows. That is, an electrode is added to CIJIII9 and connected to one terminal of a DC power supply, and the other terminal of the same power supply is connected to PB.
Connect the boards. Then, by immersing the substrate 11 and the PB board in plating in a lead borofluoride bath or a lead sulfamine bath, and applying electricity from a DC power source, Cut! Pb 1120 with a thickness of about several μm is formed on 119 by electrolytic plating.

Next, CLJII! The substrate 11 on which the I9 and Pb films 20 are formed is oxidized by heating in an oxygen atmosphere, and the Cu2O film 21 and Pi)OjI! 22. The PbO film 22 forms a secondary electron emission surface 23.

Next, an acceleration electrode is formed by a lift-off method. That is, as shown in FIG. 2(f), a photoresist (negative resist) 24 is applied to a thickness of several μm on one surface of the substrate 11, and this resist 24 is coated with a microscopic resist from the other surface of the substrate 11. After exposure is performed by irradiating light 25 through channel 12, development is performed. Through this step, the resist 24 is applied only on the microchannel 12 as shown in FIG.
It remains like a lid covering 2.

Then, as shown in FIG. 2(h), the photosensitive glass substrate 1
The acceleration electrode 13 is placed on the surface on which the resist 24 of No. 1 is formed.
For example, a Fe-Cr film or a C
An r-Ni film is deposited by vacuum evaporation. Next, the resist 24 and the metal film 26 thereon are removed by immersing the entire body in a resist stripping solution.
As shown in i), only the portion other than the upper portion of the microchannel 12 remains, and this forms the acceleration electrode 13.

Hereinafter, the photosensitive glass substrate 11 is turned upside down and shown in FIG.
By repeating the steps f) to (i), Figure 2 (j)
As shown in FIG.
form. In this way, the microchannel plate shown in FIG. 1 is completed.

By combining this microchannel plate with a photocathode 2 and an anode/phosphor screen 8 as shown in FIG. 3, an image intensification system can be constructed.

In addition, in the present invention, the secondary electron emitting surface 23 is the above-mentioned P
21 of bO/Cu2O! The structure is not limited, and any material may be used as long as it can be attached to the photosensitive glass substrate 11 and has a secondary electron emission function. Acceleration electrode 13
The constituent materials are also not limited to those mentioned above.

Further, in the embodiment, the shape of the photosensitive glass substrate 11, that is, the outer shape of the microchannel plate is circular, but any shape such as square, rectangle, polygon, etc. can be selected depending on the application.

By changing the mask, the microchannels 12 can be formed to have various diameters, aperture ratios, or shapes such as circular or rectangular shapes. Furthermore, by changing the irradiation angle of the ultraviolet rays 16 in the exposure step with the ultraviolet rays 16 shown in FIG. 2(a), it is also possible to change the angle of the microchannels 12 with respect to the surface of the photosensitive glass substrate 11. .

In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] According to the present invention, a microchannel plate having a large number of microchannels can be manufactured at low cost through a simple manufacturing process. In addition, since there are no particular restrictions on the size and shape of the photosensitive glass substrate used, large areas and various shapes can be easily realized.Furthermore, the shape, dimensions, and angle of the microchannels can be controlled by the exposure mask. Various selections can be made depending on the irradiation angle of ultraviolet rays, etc.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the schematic structure of a microchannel plate according to an embodiment of the present invention, and FIGS. 2(a) to (j)
3 is a schematic diagram of an image intensification system using a microchannel plate, and FIG. FIG. 3 is a diagram for explaining the principle of secondary electron multiplication. 1... Input light, 2... Photocathode, 3... Photoelectron,
4... Microchannel plate, 5... Microchannel, 6a, 6b... Acceleration electrode, 7...
Secondary electron, 8... L pole and fluorescent screen, 11... Photosensitive glass substrate, 12... Microchannel, 13...
1iffi for acceleration, 14... Pore, 15... Mask, 16... Ultraviolet light, 17... Mask, 18... Ultraviolet light, 19... Cu1l, 20... Pb1l, 2
1-cU20 membrane, 22...PboIl! , 23...
Secondary electron emission surface, 24... Negative resist, 25...
Light, 26...metal film. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 1 Figure 2 (1) Figure 2 (2)

Claims (5)

[Claims] (1) A plate-shaped photosensitive glass substrate in which a plurality of microchannels are formed along the thickness direction, a secondary electron emitting surface formed on the inner surface of the microchannels of this photosensitive glass substrate, and a secondary electron emitting surface formed on the inner surface of the microchannels of this photosensitive glass substrate; A microchannel plate comprising acceleration electrodes formed on both sides of the photosensitive glass substrate so as to partially electrically contact the electron emitting surface. (2) A plate-shaped photosensitive glass substrate made of a material that crystallizes when irradiated with ultraviolet rays is irradiated with ultraviolet rays through a mask with multiple pores, and the portions irradiated with ultraviolet rays are etched away and etched along the thickness direction. a step of forming a plurality of microchannels; a step of forming a secondary electron emitting surface on both surfaces of the photosensitive glass substrate and an inner surface of the microchannel; and a step of forming a secondary electron emitting surface on both surfaces of the photosensitive glass substrate. A method for manufacturing a microchannel plate, comprising the steps of: forming an acceleration electrode by a lift-off method. (3) In the step of forming the secondary electron emission film, a Cu film is formed on both sides of the photosensitive glass substrate and the inner surface of the microchannel by electroless plating, and a Pb
A method for manufacturing a microchannel plate according to claim 2, characterized in that the film is formed by electrolytic plating and then the Cu film and Pb film are oxidized to form a secondary electron emitting surface. . (4) The method for manufacturing a microchannel plate according to claim 3, characterized in that the Cu film and the Pb film are oxidized by heating in an oxygen atmosphere. (5) In the step of forming the acceleration electrode, a negative resist is formed on one surface of the photosensitive glass substrate, and this resist is exposed from the other surface of the photosensitive glass substrate through the microchannel. By developing,
Claim 2, characterized in that the resist is left on the microchannel, a metal film serving as an acceleration electrode is deposited thereon, and then the resist and the metal film thereon are removed. A method for manufacturing a microchannel plate.