Optical collimator based on magnetic particles and low-melting-point glass and manufacturing method thereof

Abstract

The invention discloses a light collimator based on magnetic particles and low-melting-point glass and a manufacturing method thereof. The manufacturing method comprises the following steps: uniformly mixing a low-melting-point glass raw material and the magnetic particles; the melting point of the low-melting-point glass is 300 DEG C to 500 DEG C; placing the obtained mixture in a heating device, and controlling the heating temperature to be within the melting point range of the low-melting-point glass raw material and to be lower than the Curie temperature of the magnetic particles; then adding a dispersing agent; pouring the uniformly mixed solution into a mold, and placing the mold in a uniform magnetic field with an unchanged magnetic field direction, so that the magnetic particles are arranged into a plurality of chain-shaped aggregates parallel to the magnetic field direction under the action of the magnetic field, and the chain-shaped aggregates are parallel to one another; and after complete cooling and solidification, the magnetic field effect is removed, and the optical collimator based on the magnetic particles is manufactured. Therefore, the technical problems that an existing optical collimator is poor in high temperature resistance and corrosion resistance and limited in light-transmitting wave band are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of light collimation, and particularly relates to a light collimator based on magnetic particles and low-melting-point glass and a manufacturing method thereof. BACKGROUND

[0002] In light imaging technology, a collimator is often used to limit stray light that is not transmitted through a measured object to reduce noise.

[0003] Existing collimators mainly include a multi-leaf collimator and a micro-channel plate collimator for X-ray imaging. The multi-leaf collimator adjusts the shape of a radiation beam by driving each leaf to move. A commonly used Varian collimator is composed of 60 pairs of multi-leaf collimators, and the thickness of the leaves is at least 5 mm. The thinner the leaf, the more accurate the generated sub-field, but the structure is also more complex, and the price is more expensive. The multi-leaf collimator is more prone to leakage problems. In practice, it is difficult to balance the contradiction between design precision and clinical application. Moreover, the multi-leaf collimator is often driven by a motor, and the speed of the leaf movement is limited, which is not flexible enough.

[0004] In 1980, researchers first proposed the application of a micro-channel plate to X-ray collimation. The micro-channel plate collimator is made of high-lead glass and contains several micron-sized collimation channels in the interior. The high-lead content and the high-roughness inner wall of the channels are used to absorb stray X-rays. Compared with the traditional leaf collimator, the micro-channel collimator has higher resolution, smaller volume, lighter weight, and can be arrayed and spliced to achieve large-area collimation. However, the manufacturing process of the micro-channel plate is complex, the micro-holes are prone to blockage and deformation, and the stability of the glass material cannot be considered. The long-term stability is poor. In the existing glass-based collimator related technology, there is still a lack of solutions that can simplify the process and ensure stability. Moreover, the existing light collimator has poor high-temperature resistance, poor corrosion resistance, and limited light transmission band. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a light collimator based on magnetic particles and low-melting-point glass and a manufacturing method thereof, thereby solving the technical problems of poor high-temperature resistance, poor corrosion resistance, and limited light transmission band of the existing light collimator.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a manufacturing method of a light collimator based on magnetic particles and low-melting-point glass is provided, comprising the following steps: (1) uniformly mixing low-melting-point glass raw materials and magnetic particles; the melting point of the low-melting-point glass raw materials is 300℃-500℃; (2) placing the mixture obtained in step (1) in a heating device, and controlling the heating temperature to be higher than the melting point range of the low-melting-point glass raw materials and lower than the Curie temperature of the magnetic particles; (3) after the low melting point glass raw material is completely melted into liquid state, a dispersing agent is added to make the magnetic particles and the dispersing agent uniformly dispersed in the glass melt; (4) the mixed solution is poured into a mold, and the mold is placed in a uniform magnetic field with unchanging magnetic field direction, so that the magnetic particles are arranged into several chain-like aggregates parallel to the magnetic field direction under the action of the magnetic field, and each chain-like aggregate is parallel to each other; (5) after the mixed solution in the mold is completely cooled and solidified, the magnetic field is removed, and a light collimator based on magnetic particles is prepared.

[0007] Preferably, the magnetic particles are rare earth element-containing magnetic particles or FePt nanoparticles.

[0008] Preferably, the rare earth element-containing magnetic particles are or .

[0009] Preferably, the particle size of the magnetic particles is 0.1 nm to 100 μm.

[0010] Preferably, the surface of the magnetic particles is coated with heavy metals.

[0011] Preferably, the heavy metals are selected from one or more of tungsten, gold, bismuth, molybdenum and antimony.

[0012] Preferably, the low melting point glass raw material is selected from bismuth borate glass, phosphate glass or fluoride glass.

[0013] Preferably, the mass ratio of the low melting point glass raw material to the magnetic particles is 100: (0.05-35).

[0014] Preferably, the dispersing agent is selected from nano-silicon dioxide, nano-aluminum oxide and silane coupling agent; and the mass ratio of the dispersing agent to the magnetic particles is 0.1%-5%.

[0015] Preferably, the uniform magnetic field with unchanging magnetic field direction is generated by a permanent magnet; and the magnetic field strength of the magnetic field is 1000 Gauss to 5000 Gauss.

[0016] Preferably, the mold is a cuvette; the solidification temperature is 10-30℃, and the solidification time is 24-72 h.

[0017] Preferably, in step (2), the heating rate is 5℃ / min to 15℃ / min.

[0018] According to another aspect of the present application, a light collimator based on magnetic particles and low melting point glass prepared by the manufacturing method is provided.

[0019] According to another aspect of the present application, a method for collimating light by using the light collimator is provided, wherein a light source is irradiated to the light collimator, and the irradiation direction of the light source is parallel to the chain-like aggregate formed by the magnetic particles in the light collimator, so as to realize light collimation.

[0020] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects: 1、The low-melting-point glass raw material is added in the light collimator to fix the magnetic particles, compared with the materials used in the prior art, the low-melting-point glass raw material used in the present application is more resistant to high temperature, corrosion and has stronger stability, will not deform or degrade in performance due to excessive temperature, can resist the corrosion of most chemicals, and maintain the integrity of its own structure and optical performance, thereby continuously and stably collimating light to ensure the normal operation of the optical system; and the light collimator prepared by using the low-melting-point glass raw material has a more extensive light transmission band, the electronic structure of the atoms and molecules in the glass causes less light absorption in a specific wavelength range, allowing more bands of light to pass through.

[0021] 2、The magnetic particles selected in the present application are rare earth element-containing magnetic particles or FePt nanoparticles, which can maintain magnetism during the high-temperature melting process of the glass, ensuring the formation of stable chain-like aggregates under the action of a magnetic field and realizing effective collimation of light.

[0022] 3、The present application controls the heating temperature to be higher than the melting point range of the low-melting-point glass raw material and lower than the Curie temperature of the magnetic particles, which aims to ensure that the glass raw material is in a molten liquid state on the one hand, and to avoid demagnetization of the magnetic particles due to high temperature on the other hand.

[0023] 4、The surface of the magnetic particle powder in the present application is coated with heavy metals, which can absorb radiation, allowing transmitted light to pass through, and the light scattered in other directions and the original incident light have a directional difference, which will be absorbed by the magnetic particles when passing through the collimator, rather than passing through the collimator from the gap like the transmitted light, and the heavy metals can absorb more radiation, i.e., can strengthen the filtering of stray light.

[0024] 5、The materials used in the present application are low-cost magnetic particle powder and low-melting-point glass raw material, and the manufacturing process is simple, which can be completed through steps such as heating and melting, stirring and mixing, and cooling and solidification in a magnetic field, and the size and shape required for clinical application can be flexibly manufactured according to actual needs. The glass light collimator manufactured by solidification is convenient to use, and the glass material and the chain-like aggregate structure of the magnetic particles have strong stability, which does not need to be cleaned and maintained like a micro-channel plate, and does not need to be calibrated before each use like a multi-leaf collimator, and can be used to collimate light of multiple wavelength bands. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1This is a schematic diagram illustrating the fabrication method of the optical collimator based on magnetic particles and low-melting-point glass according to the present invention.

[0026] Figure 2 This is a schematic diagram of the optical collimator structure based on magnetic particles and low-melting-point glass of the present invention.

[0027] Figure 3 This is a schematic diagram of the collimation principle of the optical collimator based on magnetic particles and low-melting-point glass in this invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Example 1 like Figure 1 As shown, the present invention provides a method for manufacturing an optical collimator based on magnetic particles and low melting point glass, which includes the following steps.

[0030] Step S1: Mix 10g of bismuth borate glass raw material and 0.01g of magnetic particle powder with a particle size of 10μm. Place it in a ceramic crucible and stir to mix thoroughly.

[0031] Step S2: Place the ceramic crucible in the heating device and slowly heat it at a rate of 10℃ / min to avoid localized overheating or uneven heating of the glass melt, while reducing the generation of bubbles in the glass melt. Control the heating temperature within the glass melting point range and below the Curie temperature of the magnetic particles to prevent the magnetic particles from losing magnetism due to high temperature. The heating temperature is 450℃, which melts the bismuth borate glass powder without causing the magnetic particles to lose their magnetism.

[0032] Step S3: After the glass has completely melted and become liquid, add 0.01 mg of dispersant nano silica and stir in the same direction with a high-temperature resistant stirring rod to make the magnetic particles evenly dispersed in the glass melt.

[0033] Step S4: Pour the well-mixed solution into a cuvette, which is 12.5 mm long, 12.5 mm wide, and 45 mm high. Place it in a magnetic field, where the magnetic field strength is generated by a pair of cylindrical permanent magnets. The magnetic field strength is 5000 Gauss and has good uniformity. Under the action of the magnetic field, the particles are arranged into chain-like aggregates parallel to the direction of the magnetic field.

[0034] Step S5, waiting for the sample to completely cool and solidify, the cooling and solidification ambient temperature is room temperature 25℃, the solidification time is 72 hours; after the solidification is completed, the magnetic field effect is removed, and a light collimator based on magnetic particles and low melting point glass is prepared. The chain direction formed in the light collimator is consistent with the direction of the magnetic field, the chain cross-sectional size is in the order of microns, and the length size is in the order of millimeters. The prepared light collimator is as shown in Figure 2 .

[0035] Under the external magnetic field, the magnetic particles are attracted in the direction parallel to the magnetic field and are repelled in the direction perpendicular to the magnetic field. When the external magnetic field is applied, the originally randomly oriented particles gather to form chains arranged along the direction of the magnetic field, and are secondarily gathered in the transverse direction to form thicker columns. The transmission light parallel to the chain direction can pass through the collimator, and the light perpendicular to the chain direction can hardly pass through. The larger the included angle between the collimator chain and the light direction, the better the filtering effect on the non-transmission light, so that the stray light is limited by controlling the included angle.

[0036] Figure 3 is a schematic diagram of the light collimation principle of the light collimator based on magnetic particles and low melting point glass of the present application. In use, the light source is irradiated to the light collimator, so that the light source irradiation direction is parallel to the chain-shaped aggregate formed by the magnetic particles in the light collimator, so that light collimation is realized.

[0037] Example 2 As shown in Figure 1 , the present application provides a manufacturing method of a light collimator based on magnetic particles and low melting point glass, comprising the following steps: Step S1, put 10g of phosphate glass raw materials and 0.01g of magnetic particles FePt nanoparticles with a particle size of 0.1nm into a ceramic crucible, and stir and mix uniformly. The surface of the magnetic particles FePt nanoparticles is coated with tungsten metal which can absorb radiation.

[0038] Step S2, place the ceramic crucible in a heating device, slowly heat at a heating rate of 5℃ / min, control the heating temperature in the glass melting point range, and lower than the Curie temperature of the magnetic particles, so as to avoid demagnetization of the magnetic particles due to high temperature. The heating temperature is 400℃, so that the glass powder is melted and the magnetic particles do not lose magnetism.

[0039] Step S3, after the glass is completely melted into a liquid state, 0.05mg of dispersant nano-alumina is added and stirred in the same direction by a high-temperature resistant stirring rod, so that the magnetic particles are uniformly dispersed in the glass melt.

[0040] Step S4, pour the mixed solution into a cuvette, the size of the cuvette is 12.5mm long, 12.5mm wide, and 45mm high. Place the cuvette in a magnetic field, so that the magnetic particles arrange into chain-like aggregates parallel to the direction of the magnetic field under the action of the magnetic field. The magnetic field strength is generated by a pair of cylindrical permanent magnets, the magnetic field strength is 1000 Gauss, and the uniformity is good.

[0041] Step S5, wait for the sample to completely cool and solidify, remove the magnetic field, and make a magnetic particle and low-melting-point glass-based optical collimator. The cooling and solidification environment temperature is room temperature 25℃, and the solidification time is 48 hours. The chain direction formed in the optical collimator is consistent with the direction of the magnetic field, the chain cross-sectional size is in the order of microns, and the length size is in the order of millimeters.

[0042] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for fabricating a magnetic particle and low melting point glass based light collimator, characterized by, The method comprises the following steps: (1) mixing low-melting-point glass raw materials and magnetic particles uniformly; the low-melting-point glass raw materials have a melting point of 300-500℃; (2) placing the mixture obtained in step (1) in a heating device, and controlling the heating temperature to be higher than the melting point range of the low-melting-point glass raw materials and lower than the Curie temperature of the magnetic particles; (3) after the low-melting-point glass raw materials are completely melted into a liquid state, adding a dispersing agent to uniformly disperse the magnetic particles and the dispersing agent in the glass melt; (4) pouring the uniformly mixed solution into a mold, and placing the mold in a uniform magnetic field with an unchanged magnetic field direction, so that the magnetic particles are arranged into a plurality of chain-like aggregates parallel to the magnetic field direction under the action of the magnetic field, and each chain-like aggregate is parallel to each other; (5) after the mixed solution in the mold is completely cooled and solidified, removing the magnetic field to obtain a light collimator based on magnetic particles.

2. A method of fabricating a magnetic particle and low melting point glass based optical collimator as claimed in claim 1, wherein, The magnetic particles are rare earth element-containing magnetic particles or FePt nanoparticles; the rare earth element-containing magnetic particles are or ; and the particle size of the magnetic particles is 0.1 nm to 100 μm.

3. The method of claim 1, wherein the low melting point glass is a glass having a melting point of 500 °C or less. The surface of the magnetic particles is coated with heavy metals; the heavy metals are selected from one or more of tungsten, gold, bismuth, molybdenum, and antimony.

4. The method of claim 1, wherein the low melting point glass is a glass having a melting point of 500 °C or less. The low-melting-point glass raw materials are selected from bismuth borate glass, phosphate glass, or fluoride glass.

5. The method of claim 1, wherein the low melting point glass is selected from the group consisting of PbO, Bi2O3, and a mixture thereof. The mass ratio of the low-melting-point glass raw materials to the magnetic particles is 100: (0.05-35).

6. The method of claim 1, wherein the low melting point glass is a glass having a melting point of 500 °C or less. The dispersing agent is selected from nano-silicon dioxide, nano-aluminum oxide, or a silane coupling agent; the mass ratio of the dispersing agent to the magnetic particles is 0.1%-5%.

7. The method of claim 1, wherein the low melting point glass is a glass having a melting point of 500 °C or less. The uniform magnetic field with an unchanged magnetic field direction is generated by a permanent magnet; the magnetic field strength of the magnetic field is 1000-5000 gauss.

8. The method of claim 1, wherein the low melting point glass is a glass having a melting point of 500 °C or less. The mold is a cuvette; the solidification temperature is 10-30℃, and the solidification time is 24-72h.

9. The light collimator based on magnetic particles and low-melting-point glass prepared by the method according to any one of claims 1-8.

10. A method of collimating light using the light collimator of claim 9, characterized in that, A light source is irradiated to the light collimator, the irradiation direction of the light source is parallel to the chain-like aggregates formed by the magnetic particles in the light collimator, so that light collimation is achieved.

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