KR20140032669A

KR20140032669A - X-ray grid and its fabrication method

Info

Publication number: KR20140032669A
Application number: KR1020120099238A
Authority: KR
Inventors: 조수제
Original assignee: 조수제
Priority date: 2012-09-07
Filing date: 2012-09-07
Publication date: 2014-03-17

Abstract

The present invention relates to an X-ray grid used for taking an X ray and includes irradiating photosensitive glass at a specific angle with a ultraviolet stepper or a ultraviolet laser, thermally treating the photosensitive glass exposed to ultraviolet, chemically etching a crystallized part after thermal treatment, and filling a chemically etched part with an X ray shielding member or forming the X ray shielding member on the wall of the chemically etched part. According to the present invention, in addition to a typical stripe-shaped X-ray gird, various shapes such as a quadrilateral shape, a circular shape, and a honeycomb shape may be taken, and it is possible to fabricate a high-resolution X-ray grid. There is an effect in that it is possible to fabricate an X-ray grid having high-resolution and various shapes in simpler and more precise fashions when compared to a typical method of fabricating a stripe type by sequentially cutting and bonding lead and aluminum or a synthetic resin film.

Description

X-ray grid and its fabrication method

Medical Industrial Radiography

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to diagnostic radiography, which is widely used in the medical field, and more particularly, to an x-ray scattering prevention grid for improving the contrast of an image during x-ray imaging.

During X-ray imaging, the x-rays penetrate an object such as a human body from the x-ray source. Some of the transmitted radiation passes directly through the object to reach the X-ray detector, producing an X-ray image on the photosensitive film or other suitable detector. However, some other radiation scattered from the object reaches the x-ray detector in a path that is significantly different from the original path.

When the scattered radiation reaches the X-ray detector of the other part, the distorted information is obtained by the scattered radiation and adversely affects the contrast of the image.

To compensate for the drop in contrast characteristics, the radiation dose is also increased, which can increase anxiety for a person. When the scattered radiation is reduced or eliminated, the amount of radiation projected on the human body is reduced, and the contrast of the image can be improved.

In order to achieve this effect, an X-ray grid is usually installed on the back of the object to remove scattered x-rays.

X-ray grids are generally manufactured by bonding sheets of high-density material, such as lead, which shields the x-rays, and sheets of low-density material, such as aluminum, which transmits the x-rays, and then cutting the cut pieces to a predetermined width and arranging them according to the angle at which the x-rays are incident. .

In this manner, a stripe-shaped X-ray grid is produced. In this case, scattering to the wall surface is prevented, but scattering to the side surface occurs.

This is illustrated in [Fig. 1].

The X-rays 1-2 are irradiated from the X-ray light source 1-1 in each direction, and the irradiated X-rays penetrate the object 1-3 (for example, the human body) and pass through the grid 1-4 to detect at the detection stage. Will be detected. The X-ray grid is mainly composed of a transmissive material (1-4_1; for example, aluminum or polymer sheet) and a shielding material (1-4_2) that transmit X-rays. In the transmissive material, X-rays passing through the human body pass through the human body information at the detection stage. In the X-ray shield, it serves to shield the scattered signal of the X-rays passing through the human body. Therefore, the x-ray shielding material must be aligned with the x-ray direction coming from the x-ray light source. That is, each X-ray shield 1-4_2 is inclined at a predetermined angle according to the distance between the X-ray light source and the grid as shown in the figure.

The X-ray grid of the Linear Focused method (1-6), which is the most widely used method, is shown here. The X-ray shields constituting the X-ray grid are all standing vertically (1-5). In this case, since each X-ray should be irradiated in parallel, it is inevitably small size or expensive in terms of apparatus.

The Criss Cross-based X-ray grid was created to mitigate the adverse effects of scattering along the wall of the x-ray shield.

In order to solve problems in the manufacturing process and to manufacture a more precise x-ray grid, US Patent US005418833 shows the manufacture of a photolithography-based x-ray grid. As is well known, when the photolithography process is used, there is an advantage of manufacturing grids of various shapes that can be drawn in the drawings. As shown in the figure, the silicon is etched to an arbitrary depth using a photolithography process and an etching technique, and then the X-ray shield is coated on the wall to transmit the X-ray through the silicon portion and the etched portion without the shield, Where there is a shield, scattered x-rays are absorbed.

In the past, the etching method of silicon used to vertically dig when etching a silicon wafer having 110 crystal directions with potassium hydroxide or the like, but recently, technologies for forming very fine holes by anisotropic etching of silicon in semiconductor processes, etc. It is developed and used, and various X-ray grids using this method are attempting in various forms.

In the case of making an X-ray grid using such silicon, there is an advantage in that an X-ray grid having an arbitrary drawing such as a stripe shape, a rectangle, or a circle can be manufactured. Since it is difficult to process inclined to match the X-ray apparatus, it can be applied only to limited fields such as a compact X-ray apparatus or a method of scanning X-rays.

In addition, the size of silicon is only 12 inches, which is a problem in the large area of the X-ray grid.

Korean Patent Publication No. 10-2011-0090275 is one of the patents for providing the X-ray grid of various shapes by the photolithography process. This is by adhering or coating the X-ray shielding layer on the X-ray transmissive layer, making an X-ray transmissive pattern by a photolithography process, and then stacking several sheets. When manufacturing a product in such a form, it can cope with various shapes such as stripe shape, square shape, honeycomb shape, etc., but the problem of having to align at a very fine angle between the shielding material pattern that requires a fine line width and laminating thin sheets When dealing with this, there are various problems including handling difficulties.

An object of the present invention is to provide a method that can be produced in a variety of forms, such as a stripe shape, square shape, circular shape, honeycomb shape, which is derived from such a background and corresponding to the angle at which the X-ray is projected.

The object of the present invention is to more precisely produce an X-ray grid having a predetermined angle corresponding to the projected X-rays.

To this end, the photosensitive glass is irradiated with an ultraviolet lamp or a laser, and the photosensitive glass is irradiated. Filling the x-ray shield.

According to the present invention, it is possible to provide not only the existing linear X-ray grid but also various types of high precision grids such as square, circle, honeycomb, and the like. In addition, it is possible to implement a linear parallel X-ray grid with parallel light ultraviolet rays, and it is possible to adjust the tilt angle of the grid by arbitrarily adjusting the tilt angle at which the laser is irradiated to correspond to the irradiation angle of the X-ray directly incident from the X-ray light source. It is effective to provide X-ray grid of Linear Focused type.

In addition, the manufacturing process is simplified, defect rate is reduced, and the X-ray grid of high resolution is provided.

[Figure 1]
1-1 X-Ray Light Source X-Ray Generated by 1-2 X-Ray Light Source
1-3 Subjects 1-4 X-ray Grid
[Figure 2]
11 silicon 12 etching surface
13 x-ray shield
[Figure 3]
3-1 Photosensitive Glass 3-2 Ultraviolet Light Source
3-5 Forms left at the center after etching on both sides 3-6 Forms left at the bottom by etching on one side 3-7 Forms etched through
3-8 X-ray Shield Filled
[Figure 4]
4-1 Photosensitive glass 4-2 Laser light
4-4 Crystallized State after Exposure and Heat Treatment
4-5 Etched After Exposure
4-6 X-ray Shield Filled

Photosensitive glass technology was discovered in 1947 by Dr. Stucky of Corning, USA, and has been widely used in vessels such as Corel and Corningware.

However, as advanced micro-machining technology is required throughout the industry today, it has recently been developed into various core components for high-tech devices.

The technique uses a phenomenon in which ultraviolet rays of a specific wavelength are irradiated on a glass and then heat-treated to crystallize the irradiated portion, and the crystallization site is selectively removed from an aqueous hydrofluoric acid solution to enable extremely fine micromachining.

The inventor has published a paper in the International Material Society and HARMST Society confirming that the part that does not receive light, which is the opposite of the existing one, can be crystallized, and that more precise micromachining is possible. The process of crystallizing and etching the light-receiving part is called a positive photosensitive glass method, and the phenomenon in which the part not receiving light is crystallized and etched is called a negative photosensitive glass method.

In order to manufacture the X-ray grid using the photosensitive glass, the present invention shows a method of manufacturing using the positive photosensitive glass method in a cross-sectional view [Fig. 3].

When the ultraviolet light 3-2 generated in the photosensitive glass 3-1 by a parallel light exposure machine such as an aligner is irradiated through the photomask on which the chromium pattern 3-3_2 is formed on the quartz glass 3-3_1, It becomes possible to generate an invisible photosensitive phenomenon in the exposed portion. When the exposed glass is heat-treated in this way, fine crystals grow on the exposed portions 3-4.

In this way, when the exposed portion is etched glass on both sides of the glass, it is possible to etch leaving the center portion as in (3-5). In addition, if one side is blocked and etched, it is also possible to etch only a part of the lower part as shown in (3-6). When etched through a rectangular, circular, or honeycomb shape, it is possible to create a penetrated shape as in (3-7).

When the groove is made in this way, the groove is filled with the X-ray shielding material. As the x-ray shielding material, lead is mainly used, but various materials having high density may be used, and relatively dense materials such as lead, tungsten, gold, silver, copper, and nickel and alloys thereof may be used. .

As a method of filling the shielding material, like a dielectric paste commonly used in plasma display panels, materials such as lead and tungsten, which are X-ray shielding materials, are made into fine powder and then filled into pastes or filled and baked and filled with semiconductors today. Electroplating methods, such as the copper electrode filling method of the via hole, which are commonly used in the process, and materials such as lead have a low melting point, and thus may be melted and filled only with the channel part.

In the case of filling with electroplating, plating is performed after forming a thin thin film through which electricity flows. When molten lead or lead alloy is melted and filled, materials such as lead do not have good wettability with glass and are poorly filled. Therefore, it is preferable to coat a thin film of nickel, gold, copper, silver, or an alloy containing at least one of them in advance by etching, such as by sputtering, to improve wettability and to fill the melt.

When the shielding material is filled in this way, when the X-ray grid is made, the reinforcing material is attached to the upper and lower parts as necessary.

The X-ray grid can be manufactured in this manner, but in the vertical X-ray grid, there is a problem that the X-ray grid can be used only for the X-ray grid of the linear parallel type in which the X-ray runs parallel to the groove.

In this respect, as shown in FIG. 4, a technique capable of manufacturing individual electromagnetic shielding fillers having an angle of characteristics as follows.

First, prepare photosensitive glass 4-1 to make an X-ray grid. The laser 4-2 is irradiated here at a desired angle. Through various experiments, it was confirmed that the photosensitive glass was exposed to the laser having a wavelength of 355 nm. In addition, it was confirmed that even a UV laser having a shorter wavelength of 280 nm was exposed.

As the laser proceeds to glass in air, refraction occurs. When manufacturing the X-ray grid, the laser should be irradiated in consideration of such refraction. In other words, the laser should be inclinedly exposed to the X-ray that reaches the X-ray detector directly from the X-ray light source, and should be compensated and exposed in consideration of the refraction according to the path. In other words, if the angle before the laser reaches the photosensitive glass is the angle a in FIG. 4, the actual exposed angle b should be equal to the angle of the X-ray that reaches the grid directly from the X-ray light source. That is, in consideration of refraction, the irradiation angle must be corrected. (4-3) shows photosensitive glass. The glass remains transparent to the eye, but light reactions have occurred inside.

When the temperature is raised to a temperature of about 580 degrees and heat-treated, crystallization (4-4) is achieved and the color is changed opaquely.

When this is etched in a hydrofluoric acid solution (4-5), etching forms of various shapes as shown in Fig. 3 can be obtained.

The etched photosensitive glass portion is filled with an electromagnetic shielding material.

In this way, the scattering line of the X-rays is shielded at the portion filled with the electromagnetic shielding material, and the X-rays having the information of the subject passing through the desired object are transmitted at other portions, so that accurate X-ray imaging results can be obtained.

In the present invention, the X-ray grid is manufactured by a positive photosensitive glass process in which a portion of light is etched. However, it is not necessary to describe the X-ray grid even if a negative process in which the portion of light is etched is used.

Claims

X-ray grid and manufacturing method comprising the step of exposing the photosensitive glass to ultraviolet light, the step of heat-treating the exposed photosensitive glass, the step of etching the heat-treated photosensitive glass after the exposure, and the step of filling the etched photosensitive glass portion with the X-ray shielding material

The X-ray grid according to claim 1, wherein the ultraviolet rays used for exposure are ultraviolet rays generated by a parallel light exposure machine or an ultraviolet laser.

The X-ray grid of claim 1, wherein the etching is performed on both sides of the photosensitive glass during etching, and the X-ray grid is manufactured by filling an X-ray shielding material in the etched portion with the center portion left.

The X-ray grid of claim 1, wherein the etching is performed in one direction of the photosensitive glass, and the X-ray grid is manufactured by filling an etched portion with an X-ray shielding material while leaving the opposite surface.

The X-ray grid and manufacturing method of claim 1, wherein the photosensitive glass is etched and the through-hole is made after the etching, and the X-ray shield is filled in the hole.

The X-ray grid according to claim 3 or 4, wherein the pattern of the etched pattern seen from the top has a stripe shape, a square shape, a circle shape, a honeycomb shape, and the like.

6. The x-ray grid and manufacturing method according to claim 5, wherein the surface shape of the hole has a circle, square, honeycomb shape.

In the manufacture of an x-ray grid having an inclined x-ray shield in the form of a linear focused, the x-ray grid and a method for manufacturing the x-ray grid characterized by exposing the laser to an x-ray that reaches the x-ray detector directly from the x-ray light source.

The X-ray grid of claim 8, wherein the laser has a wavelength within 280nm to 355nm.

The method of claim 1, wherein the x-ray shielding material is lead, tungsten, gold, copper, nickel or an alloy containing at least one of them.

The method of claim 1, wherein the filling method of the X-ray shielding material is filled by pulverizing and pasting the X-ray shielding material into fine powder or sintering the filled paste, and a method of manufacturing the same.

The method of claim 1, wherein the filling method of the X-ray shielding material is filled with the X-ray shielding material by the electroplating method X-ray grid and its manufacturing method

The method of claim 1, wherein the filling method of the X-ray shielding material is filled into the etched X-ray shielding material in the etching portion and then cured, characterized in that the X-ray grid and manufacturing method

14. The x-ray grid and its manufacturing method according to claim 13, wherein the x-ray shield is lead and its alloy.

The X-ray grid of claim 13, further comprising coating a lead or an alloy thereof such as nickel, copper, gold, silver, and the like with a wettable material on the wall surface of the etching portion.