A micro heater and its application

Abstract

The present application provides a micro heater, comprising an electrode and a diamond substrate; the diamond substrate comprises a substrate region and a resistance region; the resistance region is in a continuous linear shape; the electrode contacts both ends of the resistance region to form a loop. It has a temperature sensing function while heating. The micro heater is made on a diamond substrate using a laser-induced graphitization method. The micro heater described in the present application is based on all-carbon materials and does not contain metal. The diamond substrate used can provide fast thermal response and heat conduction capabilities. This micro heater also has a temperature measurement function, and there is no need to configure a temperature sensor separately.

Description

Technical Field

[0001] The invention relates to the field of micro heaters, and in particular to a micro heater. Background Art

[0002] Micro heating devices are a key component in sensors and measuring instruments such as gas sensors, micro calorimeters, gas flow meters, infrared light sources, etc. due to their many advantages such as low power, small size, fast response, low price and easy integration. They play a key role in industries and fields such as environmental monitoring, production safety, smart terminals, and wearable products.

[0003] The key to preparing micro heaters lies in structural design and material selection. The selection of materials mainly includes substrate materials and heating resistor materials. In order to improve the performance of micro heaters, the materials used must be resistant to high temperatures, corrosion, and able to withstand changes caused by thermal stress. Taking the micro-electromechanical system (MEMS) micro heater as an example, it is mainly composed of two parts: substrate material and heating resistor. The substrate material plays a mechanical support role, and usually uses materials with good insulation and mechanical properties. The function of the heating resistor is to provide a heat source. By energizing the heating resistor, the current flows through the resistor, generating Joule heat to heat the heater to a predetermined temperature. At present, the heating resistors of micro heaters on the market are mostly made of metal materials and semiconductor materials, and tungsten, titanium, platinum, nickel, polysilicon or alloy materials are more commonly used. This type of micro heater generally has the disadvantages of poor stability, short life, and complex manufacturing process. The metal heating element is easily oxidized or corroded in an air environment or certain chemical atmosphere conditions, or in a high temperature environment, resulting in a shorter life or poorer stability of the micro heater. In addition, this type of metal heating element usually uses a coating or electroplating method to cover the heating element on the substrate material. In order to produce a heating element with a specific structure, a mask and photolithography process are also required. The production method and process are relatively complex and costly. Usually, in order to better control the heating temperature, the micro heater also requires a temperature sensor to achieve the purpose of temperature measurement and feedback. Summary of the invention

[0004] In view of the shortcomings and problems of the above-mentioned existing micro-heaters, the present invention provides a simple, reliable, and excellent micro-heater and a preparation method thereof. The substrate material of the micro-heater is an artificial diamond material. Artificial diamond has good mechanical properties, corrosion resistance, and high temperature resistance. The heating resistor is a graphite material with conductivity formed by laser-induced diamond. This graphite material is prepared by laser action on a diamond substrate, and the process is relatively simple, without the need for complex processes and expensive equipment. The micro-heater is a full-carbon material and does not require a metal or alloy heating element, which can effectively avoid the shortcomings and disadvantages of metal elements and improve the stability and service life of the device. At the same time, since the graphite heating element is a thermal resistor sensitive material, its resistance value changes regularly with temperature. On the basis of calibrating the relationship between the resistance and temperature of the heating element, by testing the resistance of the heating element, the micro-heater can also have the function of a temperature sensor.

[0005] According to one aspect of the present application, a micro heater is provided.

[0006] The invention comprises an electrode, a diamond substrate and a graphite resistor embedded in the diamond substrate;

[0007] The graphite resistor is obtained by in-situ conversion of diamond material through laser action;

[0008] The graphite resistor embedded in the diamond substrate is in the shape of a continuous line;

[0009] The electrodes are in contact with both ends of the graphite resistor embedded in the diamond substrate to form a loop.

[0010] The diamond substrate is selected from single crystal or polycrystalline diamond;

[0011] The thickness of the diamond substrate is 0.05-5 mm;

[0012] Optionally, the diamond substrate has a thickness of 0.1-2 mm.

[0013] Optionally, the diamond substrate is grown and prepared by a chemical vapor deposition process;

[0014] Optionally, the diamond substrate is grown and prepared by a high temperature and high pressure process;

[0015] The line shape is a broken line shape or a curved line shape;

[0016] Optionally, the fold line shape includes a tooth shape or a sawtooth shape;

[0017] Optionally, the curved shape comprises a spiral shape.

[0018] The following steps are involved:

[0019] The diamond substrate is scanned by laser, and the scanning path is the continuous line shape, so that the diamond on the surface of the diamond substrate passed by the scanning path is converted into graphite, and electrodes are placed on the surface of the diamond substrate. The electrodes are in contact with the graphite resistors at both ends of the line shape to form a loop, thereby obtaining the micro heater.

[0020] The laser emitting the laser is selected from one of a continuous laser, a nanosecond laser, a picosecond laser or a femtosecond laser;

[0021] The wavelength of the laser is selected from one of 355nm, 532nm, 800nm, 1064nm or 10600nm.

[0022] The temperature for converting the diamond on the surface of the diamond substrate into graphite is 700-3550°C.

[0023] The diamond substrate is placed on a moving platform;

[0024] The laser beam is fixed;

[0025] The position where the laser scans the diamond substrate is moved by moving the moving platform.

[0026] Optionally, the diamond substrate is fixed;

[0027] The laser beam is irradiated onto the diamond substrate through an optical galvanometer;

[0028] The position where the laser scans the diamond substrate is moved by adjusting the optical galvanometer.

[0029] Specifically, the micro heater described in the present application is obtained by the following process:

[0030] (1) Prepare a diamond substrate.

[0031] (2) Design the shape of the heating resistor. Typically, the heating resistor has a meandering shape.

[0032] (3) Laser-induced graphitization is selectively performed on the diamond substrate according to the designed shape of the heating resistor. The diamond in the laser action area is converted into graphite material to form a heating resistor of the desired shape.

[0033] (4) The laser-induced graphitization process of diamond material is achieved by scanning the laser on the diamond surface.

[0034] (5) Laser acts on diamond to cause it to undergo a phase change and transform into graphite material.

[0035] (6) Make electrodes at both ends of the heating element for connecting the heating power supply.

[0036] (7) Calibrate the relationship between the resistance value and temperature of the graphite heating element.

[0037] According to another aspect of the present application, an application of the above-mentioned microheater or the microheater prepared by the above-mentioned preparation method is provided, which is used in the fields of environmental monitoring, production safety, smart terminals, and wearable products.

[0038] The advantages of this application are: the micro heater described in this application is based on all-carbon materials, does not contain metal, and the diamond substrate used can provide fast thermal response and heat conduction capabilities. This micro heater also has a temperature measurement function, and no additional temperature sensor is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic structural diagram of the micro heater in Example 1 (top view);

[0040] Figure 2 is a schematic structural diagram of the micro heater in Example 1 (side view);

[0041] Figure 3 This is a physical picture of the micro heater in Example 1;

[0042] Figure 4 This is a graph showing the relationship between the temperature of the micro heater and the voltage across the electrodes in Example 1;

[0043] Figure 5 Graph showing the relationship between the temperature and resistance value of the micro heater in Example 1.

[0044] List of components and reference numerals: 1: diamond substrate, 2: graphite resistor embedded in diamond substrate, 3: electrode. DETAILED DESCRIPTION

[0045] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0046] Example 1

[0047] A 355 nm nanosecond laser is used as the laser light source, and an optical galvanometer is used to achieve laser scanning. First, the shape of the graphite resistor is designed, such as Figure 1 A piece of chemical vapor deposition (CVD) diamond with a thickness of 1 mm is placed on a carrier platform, and then an optical galvanometer is used to scan the diamond surface according to the designed shape to transform the diamond material in the laser action area from diamond phase to graphite phase, that is, a diamond is formed in situ. Figure 1 Shaped graphite heating resistors, Figure 3The actual resistor shape formed after laser scanning is shown. Electrodes are made at both ends of the graphite resistor by plating or coating with conductive materials.

[0048] Connect a DC power supply to both ends of the electrode, adjust the power supply voltage, and measure the heater temperature at the same time. The relationship between the heater temperature and the applied voltage can be calibrated, such as Figure 4 shown.

[0049] By measuring the current passing through the graphite resistor and the voltage applied to both ends of the electrode at the same time, the resistance value of the graphite resistor can be calculated. By measuring and calculating the resistance value at different temperatures, the relationship curve between resistance and temperature can be calibrated, such as Figure 5 According to this curve, the temperature measurement function can be realized by measuring the resistance.

[0050] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a micro heater, characterized in that: The following steps are involved: Scanning a diamond substrate with a laser, wherein the scanning path is a continuous line shape, so that the diamond on the surface of the diamond substrate passing through the scanning path is converted into graphite, and placing an electrode on the surface of the diamond substrate, wherein the electrode contacts the graphite resistors at both ends of the line shape to form a loop, thereby obtaining the micro heater; The wavelength of the laser is selected from one of 355nm, 532nm, 800nm, 1064nm or 10600nm; The micro heater comprises an electrode, a diamond substrate and a graphite resistor embedded in the diamond substrate; The graphite resistor is obtained by in-situ conversion of diamond material through laser action; The graphite resistor is in the shape of a continuous line; The electrodes are in contact with two ends of the graphite resistor to form a loop; The diamond substrate is selected from single crystal or polycrystalline diamond.

2. The preparation method according to claim 1, characterized in that: The thickness of the diamond substrate is 0.05-5 mm.

3. The preparation method according to claim 1, characterized in that: The thickness of the diamond substrate is 0.1-2 mm.

4. The preparation method according to claim 1, characterized in that: The line shape is a broken line shape or a curved line shape.

5. The preparation method according to claim 4, characterized in that: The broken line shape is a tooth shape.

6. The preparation method according to claim 4, characterized in that: The broken line shape is a sawtooth shape.

7. The preparation method according to claim 4, characterized in that: The curved shape includes a spiral shape.

8. The preparation method according to claim 1, characterized in that: The diamond substrate is grown and prepared by a chemical vapor deposition process.

9. The preparation method according to claim 1, characterized in that: The diamond substrate is grown and prepared by a high temperature and high pressure process.

10. The preparation method according to claim 1, characterized in that: The laser emitting the laser light is selected from one of continuous laser, nanosecond laser, picosecond laser or femtosecond laser.

11. The preparation method according to claim 1, characterized in that: The temperature for converting the diamond on the surface of the diamond substrate into graphite is 700-3550°C.

12. The preparation method according to claim 1, characterized in that: The diamond substrate is placed on a moving platform; The laser beam is fixed; The position where the laser scans the diamond substrate is moved by moving the moving platform.

13. The preparation method according to claim 1, characterized in that: The diamond substrate is fixed; The laser beam is irradiated onto the diamond substrate through an optical galvanometer; The position where the laser scans the diamond substrate is moved by adjusting the optical galvanometer.

14. An application of a micro heater prepared by the preparation method according to any one of claims 1 to 13, characterized in that: Used in environmental monitoring, production safety, smart terminals or wearable products.

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