阅读说明：本技术 一种基于x射线微像素单元的平板x射线源及其制备方法 (Flat-panel X-ray source based on X-ray micro-pixel unit and preparation method thereof ) 是由 陈军 黄佳 邓少芝 许宁生 佘峻聪 于 2019-11-12 设计创作，主要内容包括：本申请公开了一种基于X射线微像素单元的平板X射线源,包括阴极基板、阳极基板及高压绝缘隔离体；所述阴极基板和所述阳极基板相对平行设置,所述高压绝缘隔离体设置于所述阴极基板和所述阳极基板之间以将两者隔离开,还公开了一种基于X射线微像素单元的平板X射线源的制备方法,包括制作阴极基板,制作阳极基板和组装,绝缘层覆盖法可有效降低了底部阴极电极条的边缘电场,减少放电现象发生的可能,从而实现阳极电压的进一步提高,同时,可以改善器件工作稳定性,延长器件使用寿命,阳极基板上的圆形金属靶排布并与顶部阴极电极及生长源薄膜一一对应,构成阵列式排布的X射线微像素单元阵列,从而使得平板X射线源具有空间分辨率。(The application discloses a flat panel X-ray source based on an X-ray micro-pixel unit, which comprises a cathode substrate, an anode substrate and a high-voltage insulating isolator; the cathode substrate and the anode substrate are arranged in parallel relatively, the high-voltage insulation isolator is arranged between the cathode substrate and the anode substrate to isolate the cathode substrate and the anode substrate, and the preparation method of the flat-panel X-ray source based on the X-ray micro-pixel unit comprises the steps of manufacturing the cathode substrate, manufacturing the anode substrate and assembling, wherein the insulating layer covering method can effectively reduce the fringe electric field of the bottom cathode electrode strip and reduce the possibility of discharge phenomenon, so that the anode voltage is further improved, meanwhile, the working stability of the device can be improved, the service life of the device is prolonged, the circular metal targets on the anode substrate are arranged and correspond to the top cathode electrode and the growth source film one by one, and the X-ray micro-pixel unit array arranged in an array mode is formed, so that the flat-panel X-ray source has spatial resolution.)

1. A flat X-ray source based on X-ray micro-pixel units comprises a cathode substrate, an anode substrate and a high-voltage insulating isolator; the cathode substrate and the anode substrate are arranged in parallel relatively, the high-voltage insulating separator is arranged between the cathode substrate and the anode substrate to separate the cathode substrate and the anode substrate,

the cathode substrate comprises a cathode substrate, more than two bottom cathode electrode strips arranged on the cathode substrate in parallel, an insulating layer covering the bottom cathode electrode strips, etching through holes formed in the insulating layer and used for enabling the bottom cathode electrode strips to be partially exposed, a top cathode electrode formed on the insulating layer, and a growth source film arranged on the top cathode electrode, wherein a nanowire cold cathode is grown on the growth source film, and the top cathode electrode is connected with the bottom cathode electrode strips through the etching through holes;

the anode substrate comprises an anode substrate, more than two anode electrode strips arranged on the anode substrate in parallel and a circular metal target manufactured on the anode electrode strips,

each anode electrode strip and each bottom cathode electrode strip are vertically crossed in space and provided with a cross point, the top cathode electrode and the growth source film are located at the cross point, the top cathode electrodes are arranged on the bottom cathode electrode strips in an array mode, the circular metal targets are located at the cross point, the circular metal targets are arranged on the anode electrode strips in an array mode, and the growth source film and the circular metal targets form an X-ray micro-pixel unit.

2. The X-ray micro-pixel cell based flat panel X-ray source of claim 1, wherein the nanowire cold cathode is a zinc oxide nanowire, a copper oxide nanowire, a tungsten oxide nanowire, a molybdenum oxide nanowire, an iron oxide nanowire, a titanium oxide nanowire, or a tin oxide nanowire.

3. The flat panel X-ray source based on X-ray micro-pixel units of claim 1, wherein the shape of the growth source thin film is a symmetrical figure, and the diameter or side length of the growth source thin film is 5 μm-500 μm.

4. The flat panel X-ray source based on X-ray micro-pixel units of claim 3, wherein the distance between adjacent growing source films is 0.1-10 times the diameter or side length.

5. The X-ray micro-pixel cell based flat panel X-ray source of claim 1, wherein the bottom cathode electrode strips and the top cathode electrode each have a thickness in the range of 0.1 μ ι η -2 μ ι η, and the top cathode electrode is circular or polygonal in shape.

6. The X-ray micro-pixel cell based flat panel X-ray source of claim 1, wherein the thickness of the anode electrode strips is in the range of 0.1-2 μ ι η.

7. The X-ray micro-pixel cell based flat panel X-ray source of claim 1, wherein the circular metal target has a thickness of 0.2 μ ι η -1000 μ ι η.

8. A preparation method of a flat panel X-ray source based on an X-ray micro-pixel unit is characterized by comprising the following steps:

s1, manufacturing a cathode substrate and an anode substrate:

the cathode substrate comprises the following steps:

manufacturing a bottom cathode electrode strip on a cathode substrate;

covering an insulating layer on the bottom cathode electrode strip;

etching the insulating layer to manufacture an etched through hole positioned on the bottom cathode electrode strip;

manufacturing a top cathode electrode connected with the bottom cathode electrode strip on the etched through hole;

depositing a growth source film;

carrying out thermal oxidation on the growth source film to grow a nanowire cold cathode to obtain a cathode substrate;

the preparation steps of the anode substrate are as follows:

manufacturing an anode electrode strip on an anode substrate;

manufacturing a circular metal target array on the anode electrode strip to obtain an anode substrate;

s2, assembling:

arranging the cathode substrate and the anode substrate which are prepared by the steps in parallel relatively, wherein the nanowire cold cathode on the cathode substrate faces the round metal target on the anode substrate, and the growth source films correspond to the round metal target one by one;

and the cathode substrate and the anode substrate are isolated and fixed by adopting a high-voltage insulating isolator, each anode electrode strip and each bottom cathode electrode strip are ensured to be mutually vertical in space and have a cross point, and the top cathode electrode, the growth source film and the round metal target are positioned at the cross point.

9. The production method according to claim 8, wherein the thermal oxidation method comprises a temperature rise process and a temperature maintenance process, and a temperature rise rate of the temperature rise process is 1 ℃/min to 30 ℃/min; the heat preservation temperature in the heat preservation process is 300-600 ℃, the heat preservation time is 1-600 min, and the natural cooling is carried out to the room temperature after the heat preservation is finished.

10. The method according to claim 9, wherein Ar and H are introduced during the temperature raising and maintaining processes₂、N₂、O₂One or two or more of the combined gases.

Technical Field

The invention relates to a flat panel X-ray source based on an X-ray micro-pixel unit and a preparation method thereof.

Background

Chinese patent CN201811178220.8, "an addressable nano cold cathode flat X-ray source and a method for making the same", discloses a flat X-ray source using cathode electrode strips and anode electrode strips directly crossed in space, although the addressing function can be achieved, because the cathode electrode exposed outside can easily cause the problem of electrode edge discharge in high-voltage operation, thereby damaging the device, resulting in insufficient anode voltage, and unable to implement transmission imaging of high-density tissue and metal material, meanwhile, the use of the whole anode electrode strip can cause the flat X-ray source not have spatial resolution, unable to form a true X-ray micro-pixel unit array, the whole anode electrode strip does not implement true one-to-one correspondence with the growth source film, which means that other linear regions will also generate X-rays except the disk region corresponding to the growth source film, in order to maintain the conductivity, the width of the linear area of the anode electrode strip is basically unchanged, and when the number of the arrays is larger, the area of the disk area in the anode metal target electrode strip is smaller and smaller, so that the anode metal target electrode strip is more linear, the flat-plate X-ray source does not have the spatial resolution, and the application of the flat-plate X-ray source in the fields of medical imaging, industrial flaw detection, safety inspection and the like is limited to a certain extent.

Disclosure of Invention

The invention aims to provide a flat panel X-ray source based on an X-ray micro-pixel unit, which can improve the anode voltage and has spatial resolution.

The invention is realized by the following technical scheme:

a flat X-ray source based on X-ray micro-pixel units comprises a cathode substrate, an anode substrate and a high-voltage insulating isolator; the cathode substrate and the anode substrate are arranged in parallel relatively, the high-voltage insulating separator is arranged between the cathode substrate and the anode substrate to separate the cathode substrate from the anode substrate, the cathode substrate comprises a cathode substrate, more than two bottom cathode electrode strips arranged on the cathode substrate in parallel, an insulating layer covering the bottom cathode electrode strips, etching through holes which are formed in the insulating layer and enable the bottom cathode electrode strips to be partially exposed, a top cathode electrode formed on the insulating layer, and a growth source film arranged on the top cathode electrode, wherein nanowire cold cathodes are grown on the growth source film, the top cathode electrode is connected with the bottom cathode electrode strips through the etching through holes, the anode substrate comprises an anode substrate, more than two anode electrode strips arranged on the anode substrate in parallel, and a round metal target formed on the anode electrode strips, each anode electrode strip and each bottom cathode electrode strip are vertically crossed in space and provided with a cross point, the top cathode electrode and the growth source film are located at the cross point, the top cathode electrodes are arranged on the bottom cathode electrode strips in an array mode, the circular metal targets are located at the cross point, the circular metal targets are arranged on the anode electrode strips in an array mode, and the growth source film and the circular metal targets form an X-ray micro-pixel unit.

The growth source film is arranged on the top cathode electrode, and the bottom cathode electrode strip is buried under the insulating layer, so that the bottom cathode electrode strip can be prevented from being directly exposed outside, and the discharge problem caused by the edge of the electrode strip under high voltage is solved. Particularly, the growth source film can completely cover the top cathode electrode, the discharge position of the top cathode electrode is mostly arranged at the edge of the top cathode electrode, and the covering of the top cathode electrode by the growth source film is equivalent to a protection effect on the edge of the top cathode electrode.

The circular metal targets are arranged on the anode electrode strips, the growth source films and the circular metal targets can correspond one to form an X-ray micro-pixel unit, so that other linear areas outside the disc area can not generate X-rays, and when the number of arrays is increased, the arrays can still be kept in a string shape, so that the flat-panel X-ray source has spatial resolution.

The cathode substrate and the anode substrate are oppositely and parallelly arranged, so that each anode electrode strip and each bottom cathode electrode strip are vertically crossed in space and have a cross point, and the plurality of anode electrode strips and the plurality of bottom cathode electrode strips are vertically crossed, so that the cross points are arranged in an array form. The growth source film arranged on the top cathode electrode and the round metal target are positioned on the cross point to jointly form an X-ray micro-pixel unit, so that the addressing function based on the X-ray micro-pixel unit is realized.

During operation, the anode electrode strip is connected with an external high-voltage power supply, the bottom cathode electrode strip is grounded, and the voltage of the external high-voltage power supply is greater than 6 KV. When one or more of the anode electrode strips are connected with an external high-voltage power supply, one or more of the bottom cathode electrode strips are grounded, and X rays are generated at the intersection points of the anode electrode strips connected with the external high-voltage power supply and the grounded bottom cathode electrode strips; further, the external high voltage power supply voltage ranges from 10kV to 150 kV.

The rest anode electrode strips and the bottom cathode electrode strips can be selected not to be connected with an external high-voltage power supply and grounded, namely suspended. X-ray emission can be generated at the crossed position of the anode electrode strip and the cathode electrode strip of the access circuit, and X-ray emission can not be generated in units which are not accessed into the circuit, so that the number of the anode electrode strips and the cathode electrode strips in the access circuit directly influences the number of micro units in the flat-panel X-ray source.

Further, the nanowire cold cathode is a zinc oxide nanowire, a copper oxide nanowire, a tungsten oxide nanowire, a molybdenum oxide nanowire, an iron oxide nanowire, a titanium oxide nanowire or a tin oxide nanowire.

Further, the growth source thin film is prepared from any one of zinc, copper, tungsten, molybdenum, iron, titanium and tin, and the thickness of the growth source thin film ranges from 0.3 μm to 5 μm.

Furthermore, the shape of the growth source film is a symmetrical graph, and the diameter or the side length of the growth source film is 5-500 mu m; the distance between the adjacent growth source films is 0.1-10 times of the diameter or the side length. The growth source film is circular, annular or polygonal in shape.

Furthermore, the cathode substrate is composed of a large-area silicon wafer, glass, quartz glass or ceramic substrate; the bottom cathode electrode strip and the top cathode electrode are prepared by one or a combination of more of Cr, Al, Ti, Cu, ITO, IZO, AZO, FTO and LTFO, and the thickness range of the bottom cathode electrode strip and the top cathode electrode is 0.1-2 μm; the top cathode electrode is circular or polygonal in shape.

Further, the insulating layer is made of any one or a combination of silicon oxide, silicon nitride or aluminum oxide, and the thickness of the insulating layer is 1-5 μm. The number of the insulating layers is one or more, and the insulating film can be prepared by adopting a general film preparation method, such as electron beam evaporation, magnetron sputtering, chemical vapor deposition and the like.

The bottom cathode electrode strip is covered by the insulating layer, so that the direct spatial intersection of the bottom cathode electrode strip and the edge of the anode electrode strip can be avoided, the fringe electric field of the bottom cathode electrode strip is effectively reduced, the possibility of discharge is reduced, the anode voltage is further improved, the working stability of the device is improved, the service life of the device is prolonged, and the practical application of the device in the fields of medical imaging, industrial flaw detection, safety inspection and the like is widened.

Furthermore, the anode substrate is composed of a large-area silicon wafer, glass, quartz glass or ceramic substrate; the anode electrode strip is prepared by one or a plurality of combinations of ITO, IZO, AZO, FTO and LTFO, and the thickness range of the anode electrode strip is 0.1-2 μm; the round metal target is prepared by combining one or more than two of tungsten, molybdenum, rhodium, silver, copper, gold, chromium, aluminum, niobium, tantalum and rhenium, and the thickness of the round metal target is 0.2-1000 mu m. The anode electrode strips only serve as a conductive connection, and the part generating X-rays is a circular metal target.

Further, the anode electrode strip is prepared by a metal shadow mask and a vacuum coating technology, or by a photoetching technology, an etching technology, a vacuum coating technology and a stripping technology, or directly by screen printing or ink-jet printing. The vacuum coating technology comprises magnetron sputtering, electron beam evaporation and vacuum thermal evaporation, and the photoetching technology can adopt ultraviolet photoetching.

Further, the high-voltage insulating spacer is made of glass, quartz, ceramic or insulating plastic; the height of the high voltage insulating spacer is 0.5mm-100 mm.

Another object of the present invention is to provide a method for preparing a flat panel X-ray source based on X-ray micro-pixel cells, comprising the steps of:

s1, manufacturing a cathode substrate and an anode substrate:

the cathode substrate comprises the following steps:

manufacturing a bottom cathode electrode strip on a cathode substrate; covering an insulating layer on the bottom cathode electrode strip; etching the insulating layer to manufacture an etched through hole positioned on the bottom cathode electrode strip; manufacturing a top cathode electrode connected with the bottom cathode electrode strip on the etched through hole; depositing a growth source film; carrying out thermal oxidation on the growth source film to grow a nanowire cold cathode to obtain a cathode substrate;

the preparation steps of the anode substrate are as follows:

manufacturing an anode electrode strip on an anode substrate; manufacturing a circular metal target array on the anode electrode strip to obtain an anode substrate;

s2, assembling, namely arranging the cathode substrate and the anode substrate which are prepared in the steps in parallel relatively, wherein the nanowire cold cathode on the cathode substrate faces to the round metal target on the anode substrate, and the growth source films correspond to the round metal target one by one; the cathode substrate and the anode substrate are isolated and fixed by high-voltage insulating separators, each anode electrode strip and each bottom cathode electrode strip are ensured to be mutually vertical in space and to have a cross point, the top cathode electrode, the growth source film and the circular metal target are positioned at the cross point, and the circular metal target and the growth source film form an X-ray micro-pixel unit.

The bottom cathode electrode strip and the top cathode electrode are prepared by a metal shadow mask and a vacuum coating technology, or by photoetching, etching technology, vacuum coating and stripping technology, or directly by screen printing or ink-jet printing. The vacuum coating technology comprises magnetron sputtering, electron beam evaporation and vacuum thermal evaporation, and the photoetching technology can adopt ultraviolet photoetching. The etched through hole is prepared through an etching process, and general etching methods such as wet etching, reactive ion etching and the like can be adopted. The growth source film can be deposited on the top cathode electrode by a magnetron sputtering method, a vacuum thermal evaporation method or an electron beam evaporation method.

Further, the thermal oxidation method comprises a heating process and a heat preservation process, wherein the heating rate of the heating process is 1-30 ℃/min; the heat preservation temperature in the heat preservation process is 300-600 ℃, the heat preservation time is 1-600 min, and the natural cooling is carried out to the room temperature after the heat preservation is finished.

Further, Ar and H are introduced in the temperature rising process and the heat preservation process₂、N₂、O₂One or two or more of the combined gases. The growth of the zinc oxide nanowire, the copper oxide nanowire, the tungsten oxide nanowire, the molybdenum oxide nanowire, the iron oxide nanowire, the titanium oxide nanowire or the tin oxide nanowire is related to the oxygen concentration, so that the growth of the nanowire can be controlled by introducing gas to change the oxygen concentration.

Compared with the prior art, the invention has the beneficial effects that:

the nano cold cathode flat X-ray source is manufactured by adopting an insulating layer covering method, the bottom cathode electrode strip is covered by the insulating layer, the direct crossing of the bottom cathode electrode strip and the anode electrode strip in space is avoided, the fringe electric field of the bottom cathode electrode strip is effectively reduced, the possibility of discharge phenomenon is reduced, the further improvement of the anode voltage is realized, meanwhile, the working stability of the device can be improved, and the service life of the device is prolonged.

The circular metal targets are arranged on the anode electrode strips, the growth source films can be in one-to-one correspondence with the circular metal targets in the true sense to form X-ray micro-pixel units, so that other linear areas outside the disc area cannot generate X-rays, and when the number of arrays is increased, the linear areas can still be independently distributed, so that the flat X-ray source has spatial resolution, the flat X-ray source can be applied to the fields of medical imaging, industrial flaw detection, safety inspection and the like, and the image definition is facilitated, and the images can be analyzed and reconstructed in the later period.

The top cathode electrodes are arranged on the bottom cathode electrode strips in an array form, the round metal targets are arranged on the anode electrode strips in an array form, and the anode electrodes and the cathode electrodes are vertically arranged in space to emit X rays point by point, line by line and in a partition manner, so that an addressing function is realized.

Drawings

FIG. 1 is a structural cross-sectional view of a flat panel X-ray source based on X-ray micro-pixel units according to the present invention;

FIGS. 2(a) - (g1)/(g2) are diagrams of the steps in the fabrication process of a flat panel X-ray source cathode substrate based on X-ray micro-pixel units;

FIG. 3 is a schematic structural diagram of a cathode substrate of a flat panel X-ray source based on X-ray micro-pixel units according to the present invention;

FIGS. 4(a) - (c) are diagrams of the steps of a manufacturing process of an anode substrate of a flat panel X-ray source based on X-ray micro-pixel units;

FIG. 5 is a schematic structural diagram of an anode substrate of a flat panel X-ray source based on X-ray micro-pixel units according to the present invention;

FIG. 6 is a schematic diagram of the overall structure of a flat panel X-ray source based on X-ray micro-pixel units according to the present invention;

FIG. 7 is a cross-sectional view of another structure of a flat panel X-ray source based on X-ray micro-pixel units according to the present invention;

FIG. 8 is a schematic diagram of the overall structure of a nano-cold cathode flat panel X-ray source of comparative example 1;

description of the reference numerals

A cathode substrate 10, an anode substrate 20, a high voltage insulating spacer 30, a cathode substrate 11, a bottom cathode electrode strip 12, an insulating layer 13, an etched via 14, a top cathode electrode 15, a growth source film 16, a nanowire cold cathode 17, an anode substrate 21, an anode electrode strip 22, a circular metal target 23, a comparative example cathode substrate 110, a comparative example anode substrate 120, a comparative example high voltage insulating spacer 130, a comparative example cathode substrate 111, a comparative example cathode electrode strip 112, a comparative example growth source film 113, a comparative example nanowire cold cathode 114, a comparative example anode substrate 121, a comparative example anode metal target strip 122.

Detailed Description

The present invention will be further described with reference to the following embodiments.