阅读说明：本技术 一种用于多碱光电阴极基底的导电及封接薄膜及制备方法 (Conductive and sealing film for multi-alkali photocathode substrate and preparation method thereof ) 是由 陈超 龚燕妮 陈坤杨 高海鹏 李晓峰 张春先 潘治云 常乐 王光凡 杜木林 于 2021-01-14 设计创作，主要内容包括：本发明公开了一种用于多碱光电阴极基底的导电及封接薄膜及制备方法,该薄膜为在基底上的多层结构的金属薄膜,其自基底向外分别是铬层薄膜、铜层薄膜和银层薄膜,各层薄膜的厚度分别为和基于铬对玻璃材料的粘接性最好,用铬层作为最底层,蒸镀在基底表面,并用于连接多碱光电阴极引出阴极电流。铜和铬、银两种金属都具有良好的粘接性,用铜层作为中间层,蒸镀在铬层边缘位置,用于导电和粘接铬层和银层。银与铜、铟锡合金拥有良好的粘接性,用银层作为金属薄膜表面层,蒸镀位置与铜层一致,用于导电和管壳封接,保证微光像增强器的高真空度。本发明的薄膜具备良好的导电性,同时与铟锡合金具有良好的粘接性,也解决铟封漏气问题。(The invention discloses a conductive and sealing film for a multi-alkali photocathode substrate and a preparation method thereof And the chromium layer is used as the bottom layer, is evaporated on the surface of the substrate and is used for connecting a multi-alkali photocathode to extract cathode current. Copper, chromium and silver have good adhesion, and a copper layer is used as an intermediate layer and is evaporated at the edge position of a chromium layer for conducting electricity and adhering the chromium layer and the silver layer. The silver layer is used as the surface layer of the metal film, the evaporation position is consistent with the copper layer, and the silver-copper-indium-tin alloy is used for conducting and sealing the tube shell, so that the high vacuum degree of the low-light-level image intensifier is ensured. The film of the invention has good conductivity, good adhesiveness with indium-tin alloy, and solves the problem of indium sealing and gas leakage.)

1. A conducting and sealing film for a multi-alkali photocathode substrate is characterized in that:

the film is a chromium layer film, a copper layer film and a silver layer film which are evaporated on the substrate;

the chromium layer film is evaporated on the surface of the substrate and covers 4mm from the edge of the substrate to the inner side of the central step;

the copper layer film is evaporated and plated right above the chromium layer film, and the coverage range extends inwards by 6mm from the edge of the substrate;

and the silver layer film is evaporated on the surface of the copper layer film to completely cover the copper layer film.

2. The conductive and sealing film for a polybase photocathode substrate according to claim 1, wherein:

the thickness of the chromium layer film is

3. The conductive and sealing film for a polybase photocathode substrate according to claim 2, wherein:

the thickness of the copper layer film is

4. The conductive and sealing film for a polybase photocathode substrate according to claim 3, wherein:

the thickness of the silver layer film is

5. The method for preparing a conductive and sealing film for a polybase photocathode substrate according to any one of claims 1 to 4, characterized by comprising the steps of:

putting a multi-alkali photocathode substrate into a chromium plating fixture, putting a chromium source into a film plating machine, putting the fixture with the cathode substrate into the film plating machine, setting the film plating thickness, and starting film plating;

and secondly, taking out the cathode substrate plated with the chromium layer, putting the cathode substrate into a copper plating fixture, putting a copper source and a silver source into a film plating machine, setting the program of the film plating machine as a copper plating layer, setting to evaporate a silver layer after copper plating is finished, and then evaporating the silver layer.

Technical Field

The invention relates to the field of manufacturing of low-light-level image intensifiers, in particular to a conductive and sealing film for a multi-alkali photocathode substrate and a preparation method thereof.

Background

The micro-light image intensifier is a core component of the micro-light night vision device, belongs to a high vacuum device, and the conductivity and the sealing effect between a multi-alkali photocathode substrate and a tube shell of the micro-light image intensifier can directly influence the performance of the micro-light image intensifier.

When the micro-optical image intensifier works, a stable voltage needs to be applied to the cathode to obtain a stable electric field. Under the action of an electric field, electrons generated by the multi-alkali photocathode impact the microchannel plate to carry out secondary electron emission, thereby realizing electron multiplication.

When the multi-alkali photocathode is manufactured, the alkali source evaporation current is controlled according to the collected cathode photocurrent change curve, and then the manufacturing of the multi-alkali photocathode is controlled. Therefore, a good conductivity is required for the polyalkali photocathode substrate.

The low-light-level image intensifier mainly comprises an anode fluorescent screen, a tube shell and a multi-alkali photoelectric cathode, and the tightness of the multi-alkali photoelectric cathode substrate and the tube shell is an important reason for influencing the vacuum degree of the low-light-level image intensifier. The photocathode substrate is sealed with the tube shell by an indium sealing method, so that the polyalkali photocathode substrate and the indium-tin alloy are required to have good adhesion.

The sealing method of the multi-alkali photocathode substrate and the tube shell generally adopts an indium sealing method, although the indium tin alloy and the glass material have good adhesion, the proportion of air leakage of the indium sealing is still high in the actual production.

Disclosure of Invention

The multi-alkali photocathode substrate is made of glass materials and has no conductivity. Therefore, on one hand, a metal film needs to be evaporated on the surface of the multi-alkali photocathode substrate, so that the substrate has conductivity; on the other hand, in order to reduce the leakage rate of the image intensifier due to the indium sealing method, the vapor-deposited metal film for the base of the polyalkali photocathode is required to have not only good conductivity but also good adhesion to indium-tin alloy, thereby solving the problem of the leakage of the indium seal.

In order to solve the technical problems in the prior art and meet the requirements of the two aspects, the invention adopts the technical scheme that: the metal films with the multi-layer structure are evaporated on the base of the multi-alkali photocathode, so that the metal films have good conductivity on the premise of meeting the requirement of having good adhesion.

The film is a chromium layer film, a copper layer film and a silver layer film which are evaporated on the substrate, wherein the chromium layer film is evaporated on the substrate surface, the copper layer film is evaporated on the edge position of the chromium layer film, and the silver layer film is evaporated on the surface layer.

The thicknesses of the chromium layer film, the copper layer film and the silver layer film are respectivelyAnd

the preparation method of the film comprises the following steps:

putting a multi-alkali photocathode substrate into a chromium plating fixture, putting a chromium source into a film plating machine, putting the fixture with the cathode substrate into the film plating machine, setting the film plating thickness, and starting film plating;

and secondly, after the coating is finished, taking out the cathode substrate plated with the chromium layer, putting the cathode substrate into a copper plating fixture, putting a copper source and a silver source into a coating machine, setting the program of the coating machine as a copper plating layer, setting to evaporate a silver layer after the copper plating is finished, and then evaporating the silver layer.

The principle and the beneficial effects of the invention are as follows:

the chromium has the best adhesion to the glass material, so the chromium layer is selected as the bottom layer, is evaporated on the surface of the substrate and is used for connecting the multi-alkali photocathode to extract cathode current. Copper and chromium and silver have good adhesion, so that a copper layer is selected as an intermediate layer and is evaporated at the edge position of a chromium layer for conducting electricity and adhering the chromium layer and the silver layer. Silver, copper and indium-tin alloy have good adhesion, a silver layer is selected as a metal film surface layer, and the evaporation position is consistent with a copper layer, so that the low-light-level image intensifier is used for conducting and sealing a tube shell, and the high vacuum degree of the low-light-level image intensifier is ensured.

Description of the drawings:

FIG. 1: schematic diagram of the conductive sealing film layer of the photocathode substrate.

FIG. 2: the photoelectric cathode substrate conductive sealing film.

In the figure: 1-a multi-alkali photocathode substrate, 2-a chromium layer, 3-a copper layer, and 4-a silver layer.

Detailed Description

As shown in figures 1 and 2, the conductive and sealing film for the multi-alkali photocathode substrate comprises a chromium layer film, a copper layer film and a silver layer film which are evaporated on the substrate, wherein the chromium layer is evaporated on the substrate surface and covers from the edge of the substrate to the edge of the substrate4mm in the central step plane. The copper layer is evaporated right above the chromium layer film, and the coverage range extends inwards 6mm from the edge of the substrate. The silver layer is evaporated on the surface of the copper layer film to completely cover the copper layer. The thicknesses of the chromium layer film, the copper layer film and the silver layer film are respectivelyAnd

the preparation method of the film comprises the following steps:

putting a multi-alkali photocathode substrate into a chromium plating fixture, putting a chromium source into a film plating machine, putting the fixture with the cathode substrate into the film plating machine, and setting the film plating thickness to beStarting film coating;

secondly, after the film coating is finished, taking out the cathode substrate plated with the chromium layer, putting the cathode substrate into a copper plating fixture, putting a copper source and a silver source into a film coating machine, and setting the program of the film coating machine as plating firstlyAnd after copper plating of the copper layer is finished, waiting for 10min and then carrying out vapor deposition on the silver layer. The thickness of the evaporated silver layer is set to

The prior sealing technology directly uses chromium as a conducting layer and a sealing film, and uses indium tin alloy as a substrate sealing material. 400 samples are sealed by two sealing methods respectively, the existing single chromium layer conductive sealing film is used for sealing, 17 air leakage products exist in a finished product, the air leakage ratio is 4.25%, and the test resistance is 0.1 omega. When the chromium-copper-silver conductive sealing film is used for sealing, only 6 air leakage products exist in a finished product, the air leakage ratio is 1.5%, and the air leakage ratio is obviously reduced compared with that of the existing single-chromium-layer conductive sealing film. The resistance of the alloy is 0.02 omega, and the resistance value is obviously reduced compared with the resistance value of the existing method.