A method for fabricating a microchannel with adjustable tilt angle inside quartz glass

Abstract

The application discloses a method for preparing a microchannel with adjustable inclination angle in quartz glass, comprising the following steps: placing the quartz glass so that the upper surface and the lower surface of the quartz glass are both in contact with air; vertically irradiating a nanosecond infrared laser on the upper surface of the quartz glass, and setting the laser focus point of the nanosecond infrared laser on the lower surface of the quartz glass through a focusing lens; setting different scanning speeds, and making the nanosecond infrared laser focus on the lower surface of the quartz glass to scan a set distance, so that the microchannel extending from the lower surface of the quartz glass to the upper surface of the quartz glass is obtained and the inclination angle of the microchannel is adjustable. The application uses the nanosecond infrared laser to prepare the microchannel in the quartz glass, greatly reduces the preparation cost, has a high processing speed, is suitable for industrial application, does not need to design a special photoetching template, does not need other components to cooperate, has a high preparation efficiency, and realizes a low requirement. By controlling the scanning speed of the nanosecond infrared laser, the microchannel with different inclination angles can be obtained according to requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microfluidic channel preparation, and particularly to a method for preparing a microchannel with an adjustable inclination angle in a quartz glass. BACKGROUND

[0002] A microchannel is a channel structure with a micron scale, and its size range is generally between 10 microns and 1000 microns. The microchannel can be used for precise control and processing of fluids, gases and the like, and has multiple functions such as analysis, synthesis, detection and filtration. The microchannel can exist alone or form a multi-stage pipeline or a network structure.

[0003] The preparation method of the microchannel mainly includes photolithography, imprinting and transfer printing technologies, but the preparation steps of these technologies are relatively complex and the preparation efficiency is low.

[0004] A femtosecond laser is an ultrashort pulse laser with extremely narrow (10 -15 s) pulse width and extremely high peak power. Compared with long pulse laser processing, femtosecond laser processing has high precision, small heat affected zone, and can also process transparent materials. It is expected that the femtosecond laser micro-processing technology can overcome the various difficulties faced by the above-mentioned traditional processing technologies, and directly process a real microchannel in the glass material. However, the femtosecond laser is expensive and difficult to mass-produce, and the angle of the microchannel cannot be adjusted during the preparation process. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a method for preparing a microchannel with an adjustable inclination angle in a quartz glass by using a nanosecond infrared laser. The method has high preparation efficiency and low requirements, and the inclination angle of the microchannel can be adjusted during the preparation process.

[0006] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0007] A method for preparing a microchannel with an adjustable inclination angle in a quartz glass, comprising:

[0008] Placing the quartz glass so that the upper surface and the lower surface of the quartz glass are in contact with air;

[0009] The nanosecond infrared laser is incident perpendicular to the upper surface of the quartz glass, and the laser focus of the nanosecond infrared laser is set on the lower surface of the quartz glass through a focusing lens;

[0010] Different scanning speeds are set to allow the nanosecond infrared laser to focus on the lower surface of the quartz glass and scan a set distance, thereby obtaining a microchannel extending from the lower surface of the quartz glass to the upper surface of the quartz glass with an adjustable inclination angle.

[0011] Compared with femtosecond laser micro-processing technology, the technical scheme utilizes nanosecond infrared laser to prepare micro-channels in quartz glass, greatly reduces the preparation cost, and has high processing speed, and the direct writing speed can reach 100 mm / s, which is suitable for industrial application.

[0012] Compared with photoetching, stamping, and other technologies, the technical scheme does not need to design a special photoetching template, does not need other components to cooperate, has high preparation efficiency, and has low implementation requirements.

[0013] Moreover, by controlling the scanning speed of the nanosecond infrared laser, micro-channels with different inclination angles can be obtained as required. The greater the scanning speed, the more inclined the angle.

[0014] Further, in the process of focusing the nanosecond infrared laser on the lower surface of the quartz glass for scanning, a low scanning speed is first adopted to accumulate heat energy, so that a spatial non-uniform temperature field is generated on the quartz glass to form a thermal stress for reducing the strength of the quartz glass, thereby reducing the difficulty of ablation of the micro-channels in the quartz glass.

[0015] Further, the low scanning speed is 1-60 mm / s, and the amount of accumulated heat energy is 1-5 joules.

[0016] Further, different scanning speeds are set to let the nanosecond infrared laser focus on the lower surface of the quartz glass to scan a set distance, so as to obtain a micro-channel extending from the lower surface of the quartz glass to the upper surface of the quartz glass and having an adjustable inclination angle. Specifically, the damaged area ablated by the laser continuously absorbs laser energy to generate plasma moving against the propagation direction of the laser beam, the scanning speed is changed to change the component speed of the plasma along the scanning direction, and then the resultant speed of the plasma is changed to ablate micro-channels with different inclination angles. The set distance refers to the length of the micro-channel to be formed projected on the lower surface of the quartz glass.

[0017] Further, the relationship between the inclination angle and the scanning speed is as follows:

[0018] y=-0.0067x 2 -0.6600x+89.0670

[0019] Wherein, y is the inclination angle, and x is the scanning speed.

[0020] Further, the scanning speed of the nanosecond infrared laser is 1-100 mm / s.

[0021] Further, the average laser power of the nanosecond infrared laser is greater than 16 W.

[0022] Further, the laser repetition frequency of the nanosecond infrared laser is greater than 20 kHz.

[0023] Further, the placing of the quartz glass refers to the quartz glass being elevated by the gasket.

[0024] Compared with the prior art, the technical scheme has the following principles and advantages:

[0025] 1. Compared with the femtosecond laser micro-processing technology, the technical scheme uses nanosecond infrared laser to prepare micro-channels in the quartz glass, greatly reduces the preparation cost, and has a fast processing speed, with a direct writing speed of 100 mm / s, which is suitable for industrial application.

[0026] 2. Compared with the photoetching, imprinting and transfer printing technologies, the technical scheme does not need to design a special photoetching template and does not need other components to cooperate, has a high preparation efficiency, and realizes a low requirement.

[0027] 3. By controlling the scanning speed of the nanosecond infrared laser, micro-channels with different inclination angles can be obtained as needed. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the services required to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 The principle flow chart of the method for preparing a micro-channel with adjustable inclination angle in the quartz glass according to the present application;

[0030] Figure 2 The schematic diagram of using nanosecond infrared laser to process quartz glass (A is nanosecond infrared laser, B is quartz glass, C is gasket, and D is workbench);

[0031] Figure 3 The schematic diagram of the nanosecond infrared laser focus being set at the lower surface of the quartz glass and generating plasma in the damage area (E is plasma);

[0032] Figure 4 (a) to (d) are schematic diagrams of the process of scanning the nanosecond infrared laser focused on the lower surface of the quartz glass (the scanning speed is 1 mm / s);

[0033] Figure 5 The schematic diagram of the nanosecond infrared laser focused on the lower surface of the quartz glass scanning (the scanning speed is 3 mm / s);

[0034] Figure 6 and Figure 7 The local topography diagram of the micro-channel under the scanning electron microscope. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to specific embodiments:

[0036] like Figure 1 As shown in this embodiment, a method for fabricating microchannels with adjustable tilt angles inside quartz glass includes the following steps:

[0037] S1. Elevate the quartz glass piece (20mm × 50mm × 5mm) using shims, ensuring both the upper and lower surfaces of the quartz glass are in contact with air to eliminate the influence of the worktable. Figure 2 As shown;

[0038] S2. A nanosecond infrared laser is incident perpendicularly to the upper surface of the quartz glass, and its focal point is set on the lower surface of the quartz glass by a focusing lens.

[0039] The average laser power and laser repetition frequency of the nanosecond infrared laser were set to 20W and 40kHz, respectively.

[0040] S3. Set different scanning speeds, specifically 1 to 100 mm / s, and focus the nanosecond infrared laser on the lower surface of the quartz glass to scan a set distance (referring to the length of the microchannel to be formed projected onto the lower surface of the quartz glass), thereby obtaining a microchannel extending from the lower surface of the quartz glass to the upper surface of the quartz glass with an adjustable tilt angle.

[0041] In the above process, the nanosecond infrared laser first scans at a low speed of 1 mm / s, allowing heat energy to accumulate continuously. When the accumulated heat reaches 3 joules, a spatially non-uniform temperature field is generated on the quartz glass, resulting in different thermal expansion rates in different areas and the formation of thermal stress. The damaged area ablated by the laser continuously absorbs laser energy, and plasma is continuously generated, such as... Figure 3 As shown. On the one hand, thermal stress reduces the strength of quartz glass, thereby reducing the difficulty of ablating microchannels inside the quartz glass; on the other hand, due to the low scanning speed, the plasma inside the glass has enough time to continuously accumulate and absorb laser energy, and finally the high-temperature and high-pressure plasma burns out microchannels in the quartz glass.

[0042] like Figure 4 As shown, Figure 4 (b) to (d) illustrate the process of forming microchannels in quartz glass after plasma formation; Figure 4 In (b), plasma is formed and continuously absorbs laser energy, exhibiting a velocity component Vt against the direction of laser beam propagation and a velocity component Vs' caused by the laser scanning speed Vs. Figure 4 In (c), both the nanosecond infrared laser beam and the plasma moved a certain distance, and the plasma formed a microchannel as it moved along the path. Figure 4In (d), the plasma is about to break out from the upper surface of the quartz glass to form a microchannel.

[0043] Specifically, after the plasma is formed in the quartz glass, the plasma will continuously absorb the laser energy and move against the direction of the laser beam propagation, at this time, there is a velocity Vt along the thickness direction of the quartz glass. Since the laser beam is moving and scanning, the plasma also has a component velocity along the scanning direction of the laser beam.

[0044] In order to make the angle of the microchannel of the quartz glass controllable, the component velocity of the plasma along the scanning direction can be changed by changing the scanning speed, so as to change the resultant velocity of the plasma and ablate microchannels with different inclination angles. For example, as shown in FIG. 4, the nanosecond infrared laser is scanned at a speed of 3 mm / s, which gives the plasma a greater component velocity Vs', and the inclination angle of the microchannel obtained is more inclined than that in FIG. 3. Figure 5 Figure 4

[0045] The relationship between the inclination angle and the scanning speed is as follows:

[0046] y = -0.0067x 2 -0.6600x + 89.0670

[0047] wherein y is the inclination angle and x is the scanning speed.

[0048] Figure 6 and Figure 7 are the local morphology diagrams of the microchannels under the scanning electron microscope.

[0049] In addition, the inclination angle of the microchannel can be adjusted by adjusting different laser powers, laser pulse widths, repetition frequencies and scanning speeds to adapt to the internal preparation of the quartz glass with different thicknesses. For example, longer microchannels can be machined in thicker transparent materials by increasing the laser power or pulse width.

[0050] The above-described embodiments are only the preferred embodiments of the present application, and do not limit the scope of the present application. Any changes made according to the shape and principle of the present application should be covered within the protection scope of the present application.​​

Claims

1. A method for fabricating a microchannel with an adjustable tilt angle inside a quartz glass, characterized in that, The application relates to a method for manufacturing a microchannel in a quartz glass, comprising the following steps: placing the quartz glass so that the upper surface and the lower surface of the quartz glass are both in contact with air; vertically irradiating a nanosecond infrared laser on the upper surface of the quartz glass, and setting the laser focus of the nanosecond infrared laser on the lower surface of the quartz glass through a focusing lens; setting different scanning speeds to make the nanosecond infrared laser focus on the lower surface of the quartz glass to scan a set distance, so that a microchannel extending from the lower surface of the quartz glass to the upper surface of the quartz glass and having an adjustable inclination angle is obtained; in the process of making the nanosecond infrared laser focus on the lower surface of the quartz glass to scan, a low scanning speed is adopted first to accumulate heat energy, so that a spatially non-uniform temperature field is generated on the quartz glass to form a heat-induced stress for reducing the strength of the quartz glass; the low scanning speed is 1-60 mm / s, and the accumulated heat energy reaches 1-5 joules; setting different scanning speeds to make the nanosecond infrared laser focus on the lower surface of the quartz glass to scan a set distance, so that a microchannel extending from the lower surface of the quartz glass to the upper surface of the quartz glass and having an adjustable inclination angle is obtained, wherein the damaged area ablated by the laser continuously absorbs laser energy to generate plasma moving against the propagation direction of the laser beam; the scanning speed is changed to change the component speed of the plasma along the scanning direction, and then change the resultant speed of the plasma, so that microchannels with different inclination angles are ablated; the set distance refers to the length of the microchannel to be formed projected on the lower surface of the quartz glass.

2. The method of claim 1, wherein the method is characterized by: The scanning speed of the nanosecond infrared laser is 1-100 mm / s.

3. The method of claim 1 or 2, wherein the method is characterized by, The average laser power of the nanosecond infrared laser is greater than 16 W.

4. The method for making an adjustable-tilt-angle microchannel in quartz glass according to claim 1 or 2, characterized in that, The laser repetition frequency of the nanosecond infrared laser is greater than 20 kHz.

5. The method for making a microchannel with adjustable tilt angle inside quartz glass according to claim 1, characterized in that, The quartz glass is placed by means of a gasket to elevate the quartz glass.

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