Device for measuring the thermal diffusivity of materials

Abstract

To overcome the technical challenge of only being able to measure the thermal diffusivity at a single location, we provide a device for measuring the thermal diffusivity of a material. [Solution] The measuring device includes a base, a modulated laser module fixed to the base, a beam shaping and focusing module, and a drive module. Above the beam shaping and focusing module is a vacuum sample chamber module, and above the vacuum sample chamber module is an infrared camera module that can move freely up and down. The drive module drives the infrared camera module to move freely up and down. The modulated laser module emits a laser beam to the beam shaping and focusing module, the beam shaping and focusing module guides the laser beam to the vacuum sample chamber module to irradiate the material, and the infrared camera module acquires a thermal image sequence of the material after heating.

Description

Technical Field

[0001] The present invention relates to the field of material property measurement, and particularly to an apparatus for measuring the thermal diffusivity of materials.

Background Art

[0002] Due to being restricted by measurement apparatuses and calculation models, the prior art mainly focuses on the research of the thermal properties and heat transfer properties of materials at the millimeter level. When the thickness of the material decreases to the micrometer level, the most traditional and common laser flash analyzer cannot accurately evaluate its thermal properties. The laser flash method, that is, the LFA (Laser Flash Analysis) method, is to calculate the thermal diffusivity of a material based on the relationship between temperature rise and time. However, for film materials, the thickness is very thin, the heat transmission time is very short, and the infrared detector has limited sampling frequency and temperature measurement accuracy, so the heat transfer process cannot be effectively captured, and the reliability of the measurement will be significantly reduced.

[0003] Currently, film materials are widely applied in fields such as new energy and chip heat dissipation to realize special functions of industrial parts. Understanding their thermal properties is very important. The known thermal conduction test system for micrometer films can only measure the thermal diffusivity at a certain position of the sample using an infrared single-point detector, and it is necessary to displace the detection device multiple times to detect multiple positions of the sample, so it cannot measure the thermal diffusivity of micrometer-level film materials, and the measurement results are inaccurate.

Summary of the Invention

[0004] In view of the above technical problems, the present invention provides an apparatus for measuring the thermal diffusivity of materials to solve the technical problem that only the thermal diffusivity at a single position can be measured.

[0005] The present invention provides a device for measuring the thermal diffusivity of a material, comprising a base, a modulated laser module, a beam shaping and focusing module, and a drive module fixed to the base, wherein a vacuum sample chamber module is provided above the beam shaping and focusing module, and an infrared camera module that can move freely up and down is provided above the vacuum sample chamber module, the drive module drives the infrared camera module to move freely up and down, the modulated laser module emits a laser beam to the beam shaping and focusing module, the beam shaping and focusing module guides the laser beam to the vacuum sample chamber module to irradiate a material, and the infrared camera module acquires a thermal image sequence of the material after heating.

[0006] In a preferred embodiment, the drive module includes a motor and a moving module, the motor driving the moving module to move the infrared camera module freely up and down along a fixed route.

[0007] In a preferred embodiment, the moving module includes a drag chain and a slide rail, the drag chain being connected to the top of the infrared camera module, and the slide rail guiding the infrared camera module.

[0008] In a preferred embodiment, the drive module further includes an operating joystick, which drives the movement module to move freely up and down by controlling the motor.

[0009] In a preferred embodiment, the infrared camera module includes an infrared main unit and an infrared microscope objective lens, the infrared microscope objective lens being detachably connected to the infrared main unit, and the infrared main unit being fixedly connected to the drive module by a support frame.

[0010] In a preferred embodiment, the infrared microscope objective lens includes a lens converter to which at least one infrared microscope objective lens is attached.

[0011] In a preferred embodiment, the modulated laser module includes a laser and a power supply, and the infrared main unit is connected to the power supply.

[0012] In a preferred embodiment, the modulated laser module includes a laser, a power supply, and a laser output coupling fiber, the laser output coupling fiber being movably mounted on the base.

[0013] In a preferred embodiment, the vacuum sample chamber module includes a vacuum chamber and a bracket supporting the vacuum chamber, wherein the vacuum chamber is connected to a vacuum pump, the vacuum pump evacuates the vacuum chamber, and the bracket is located outside the beam shaping and focusing module.

[0014] In a preferred embodiment, a germanium glass lens is provided above the vacuum chamber, a quartz glass lens is provided on the surface of the vacuum chamber facing the beam shaping and focusing module, and the vacuum chamber is a vacuum bellows.

[0015] In a preferred embodiment, a plurality of sample holders are provided in the vacuum chamber. Preferably, the plurality of sample holders accommodate the materials of various shapes.

[0016] In a preferred embodiment, the sample holder includes single-hole or multi-hole sample holders of various dimensions.

[0017] In a preferred embodiment, the sample holder is manufactured from an insulating material for use in high-temperature environments, or from a metal material for use in room-temperature environments.

[0018] In a preferred embodiment, the beam shaping and focusing module includes a beam expander, a right-angle reflecting prism, and a convex lens, the convex lens being movably mounted above the beam expander and the right-angle reflecting prism.

[0019] In a preferred embodiment, the beam shaping and focusing module further includes an optical connecting rod fixedly connected to the convex lens, a Z-axis displacement stage, the Z-axis displacement stage being connected to the convex lens by the optical connecting rod, and the convex lens being connected to the right-angle reflecting prism by a coaxial connecting rod, and both being in the same optical path.

[0020] In a preferred embodiment, the apparatus for measuring the thermal diffusivity of the material further includes an analysis module, the infrared camera module includes an infrared main unit, the analysis module is connected to the infrared main unit, and the analysis module calculates the thermal diffusivity of the material based on the thermal image sequence.

[0021] In a preferred embodiment, the infrared main unit uses an area array infrared detector.

[0022] This invention uses a drive module to drive an infrared camera module so that it can move freely up and down. The infrared camera module, which can move freely up and down, can acquire surface images of materials in a vacuum sample chamber module, and can acquire a distribution image of the thermal diffusivity of the sample surface in a single measurement. [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic diagram of a device for measuring the thermal diffusivity of a material in one embodiment of the present invention. [Figure 2] This is a schematic diagram of a device for measuring the thermal diffusivity of a material in another embodiment of the present invention. [Figure 3] This is a schematic diagram of an operating joystick for controlling a mobile module in one embodiment of the present invention. [Figure 4]This is a schematic configuration diagram of a vacuum sample chamber module in an embodiment of the present invention. [Figure 5] This is a schematic configuration diagram of a beam shaping and focusing module in an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0024] Hereinafter, while referring to the drawings in the embodiments of the present invention, the technical means in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained on the premise that those skilled in the art do not perform creative labor all belong to the protection scope of the present invention.

[0025] Note that the following embodiments can be combined as long as there is no contradiction.

[0026] As shown in FIGS. 1 and 2, a measuring device for the thermal diffusivity of a material according to the present invention includes a base 7, a modulation laser module 2, a beam shaping and focusing module 3, a drive module, a vacuum sample chamber module 4, an infrared camera module 5, and an analysis module 6. The modulation laser module 2, the beam shaping and focusing module 3, and the drive module are fixed to the base 7, and the infrared camera module 5 is fixed to the drive module. In the embodiment shown in FIG. 1, the base 7 is provided with fixing holes 8 arranged in an array for fixing the above-mentioned respective modules.

[0027] The modulated laser module 2 generates a laser that periodically heats the material to be measured, periodically heating the material (hereinafter, film material will be used as an example) at different laser pulse frequencies. The beam shaping and focusing module 3 optimizes the quality of the modulated laser spot and generates a laser focused spot of appropriate size on the back of the sample. The vacuum sample chamber module 4 mounts and fixes the material to be measured. The infrared camera module 5 records the transient temperature distribution on the surface of the material to be measured and acquires a series of thermal image sequences. The modulated laser module 2 emits a laser beam to the beam shaping and focusing module 3. The beam shaping and focusing module 3 guides the laser beam to the vacuum sample chamber module 4 to irradiate the material. The infrared camera module 5 acquires a series of thermal images of the heated material.

[0028] As shown in Figure 1, a vacuum sample chamber module 4 is provided above the beam shaping and focusing module 3, and an infrared camera module 5 that can move freely up and down is provided above the vacuum sample chamber module 4. The beam shaping and focusing module 3 is located below the vacuum sample chamber module 4, and the modulated laser module 2 is located on one side of the beam shaping and focusing module 3 and can emit a laser beam to the beam shaping and focusing module 3. Multiple of these modules are in the same optical path.

[0029] The infrared camera module 5 includes an infrared main unit 9 and an infrared microscope objective lens 10, and the drive module includes a motor (not shown) and a movement module 11. The drive module drives the infrared camera module 5 to move freely up and down so that the material to be measured is positioned at the focal plane of the infrared camera module 5 (the focal plane of the infrared microscope objective lens 10), thereby enabling the infrared main unit 9 to acquire a clear infrared image.

[0030] In other embodiments, the motor drives the moving module 11 to move the infrared camera module 5 freely up and down along a fixed route. In the embodiment shown in Figure 1, the moving module 11 includes a drag chain 12 and a slide rail 13, the drag chain 12 being connected to the top of the infrared camera module 5, and the slide rail 13 guiding the infrared camera module 5. The drag chain 12 can be moved up and down by controlled unwinding / winding, and the slide rail 13 ensures that the infrared camera module 5 and the vacuum sample chamber module 4 are always in the same optical path by moving up and down while holding the infrared camera module 5 in the same position.

[0031] Furthermore, the drive module further includes an operating joystick, which controls the motor to drive the mobile module to move freely up and down. Therefore, the mobile module can be controlled manually or electrically. When manual control is used, the motor is controlled by the operating joystick (as shown in Figure 3) to drive the mobile module to move freely up and down. When electrically controlled, the motor is connected to a computer controller, and the motor is controlled by host computer software to drive the mobile module to move freely up and down.

[0032] In other embodiments, a motor may be used to drive the movable pair structure to achieve vertical movement of the infrared camera module 5. An electric guide rail can be used as the movable pair structure, and the infrared camera module 5 is fixed to a slide block that slides along the guide rail.

[0033] In this invention, the infrared main unit 9 can acquire a clear infrared image by adjusting the position of the infrared camera module 5 using the drive module so that the material to be measured is positioned at the focal length of the infrared microscope objective lens 10.

[0034] Furthermore, the infrared camera module 5 includes an infrared main unit 9 and an infrared microscope objective lens 10. The infrared main unit performs the function of imaging the surface of the sample to be measured using an area array infrared detector. There are two types of area array infrared detectors: cooled and uncooled. The cooled area array infrared detector has higher detection sensitivity, and specifically, an appropriate area array infrared detector can be selected according to the actual requirements. The infrared microscope objective lens 10 is detachably connected to the infrared main unit 9. Therefore, the infrared microscope objective lens 10 can be selected from various types to meet different measurement requirements. The infrared main unit 9 and the infrared microscope objective lens 10 can move up and down as a single unit. Exemplarily, the infrared main unit 9 is fixed by a support frame 14, and the infrared microscope objective lens 10 is directly connected to the infrared main unit 9. Therefore, the infrared main unit 9 is fixedly connected to the moving module 11 of the drive module by the support frame 14, and the moving module 11 moves the infrared main unit 9 together with the infrared microscope objective lens 10 by moving the support frame 14.

[0035] Furthermore, the modulated laser module 2 includes a laser and a power supply. As the laser, the MGL-F-532-SM type laser from Changchun New Industrial Optoelectronic Technology Co., Ltd. can be selected. This laser supports TTL modulation, meaning that a TTL digital signal is added to the laser power supply, the on / off switching of the laser drive current is controlled by an external signal, and the laser output frequency is further controlled.

[0036] The infrared main unit 9 is connected to the power supply and generates a specific frequency relationship so that when the infrared main unit 9 starts acquiring an image, the modulated laser module 2 emits a laser beam. Since the laser supports TTL modulation, the power supply and the infrared main unit 9 can be connected using a BNC connector cable to transmit the modulation signal, meaning that the laser output frequency is controlled by the image acquisition frequency of the infrared main unit 9. Therefore, this technology can extract phase information by analyzing the thermal wave signal and further calculate the thermal diffusivity of the material being measured using the phase information. The image acquisition frequency of the infrared main unit 9 and the laser output frequency have a 4x relationship, enabling the realization of phase-locked infrared thermography technology. Phase-locked technology includes various thermal wave processing algorithms such as the 4-point algorithm. For example, when using an infrared camera with a sampling frequency of 102.4 Hz, the modulated laser frequency may be 25.6 Hz, 12.8 Hz, 6.4 Hz, 3.2 Hz, 2.56 Hz, etc.

[0037] In embodiments of the present invention, the infrared microscope objective lens 10 is fixed to a lens converter, which may be a manually operated push-type lens converter or an electrically operated turntable-type lens converter. At least one infrared microscope objective lens 10 is attached to the lens converter, and there may be two, three, or four or more infrared microscope objective lenses 10, which can be changed manually or electrically. Different infrared microscope objective lenses 10 have different resolutions and imaging magnifications. When using a single infrared microscope objective lens 10, the single infrared microscope objective lens 10 may be directly connected to an infrared camera.

[0038] The modulated laser module 2 includes a laser, a power supply, and a laser output coupling fiber 16, the laser output coupling fiber 16 being movably mounted on the base 7. As shown in Figure 1, the bottom of the laser output coupling fiber 16 is fixed to a fixing hole 8 in the base 7 by a fixing module, and when set to be movable, it facilitates measurement of various samples and adjustment of the laser output angle.

[0039] Furthermore, the vacuum sample chamber module 4 includes a vacuum chamber and a bracket supporting the vacuum chamber, the bracket being fixed to the base 7. The vacuum chamber is connected to a vacuum pump (not shown), which evacuates the vacuum chamber, for example, a vortex vacuum pump, and the vacuum chamber is a vacuum bellows, and a vacuum rigid tube can be selected if the piping route is short and has no bends.

[0040] The bracket is provided on the outside of the beam shaping and focusing module 3, and as shown in Figure 1, the vacuum chamber is located directly above the beam shaping and focusing module 3. The laser beam passes through the beam shaping and focusing module 3 and is irradiated into the vacuum chamber. A quartz glass lens is provided on the surface of the vacuum chamber facing the beam shaping and focusing module 3, and the quartz glass lens allows the laser to reach the back surface of the sample to be measured. A germanium glass lens is covered above the vacuum chamber, and since the germanium glass lens can transmit infrared light, an infrared camera can image the surface of the sample to be measured.

[0041] Preferably, as shown in Figure 4, the vacuum chamber is provided with a plurality of sample holders 15, and the plurality of sample holders 15 are used to hold the material of various shapes. By providing several sample holders 15 for holding samples in the sample chamber, the function of measuring multiple samples at once can be realized. Multiple sample holders 15 are advantageous for arranging samples of various shapes. A porous sample holder allows for the acquisition of thermal diffusivity distribution images of multiple samples in a single loading. In the embodiment of the present invention, there are at least two sample holders 15.

[0042] Furthermore, the sample holder includes single-hole or multi-hole sample holders of various dimensions. The sample holder may also include a sample holder for use in high-temperature environments, which has the characteristic of using thermal insulation material as a bracket base, and other types include a sample holder for use in room-temperature environments. The sample holder is available in single-hole and multi-hole types with holes of various shapes and dimensions to enable the measurement of the thermal diffusivity of a single sample, multiple samples, or samples of any shape.

[0043] The sample holder is manufactured from an insulating material for use in high-temperature environments, or from a metal material for use in room-temperature environments. For example, insulating materials such as insulating ceramics and calcium silicate are used in high-temperature environments of 150°C to 500°C. Metal materials such as copper and aluminum alloys are used for room-temperature measurements in room-temperature environments of -20°C to 150°C. Preferably, the hole dimensions (length × width) of the sample holder are 5mm × 5mm, 10mm × 10mm, 20mm × 20mm, etc.

[0044] The beam shaping and focusing module 3 includes a beam expander, a right-angle reflecting prism 19, and a convex lens 18, the convex lens 18 being movably mounted above the beam expander and the right-angle reflecting prism 19. The beam expander and the right-angle reflecting prism 19 are fixed to a bottom optical platform (the optical platform is fixed to the base 7) and perform beam expansion and path refraction, while the convex lens 18 focuses the beam.

[0045] In some embodiments, as shown in Figure 5, the convex lens 18 is connected by a coaxial connecting rod 17 to a right-angle reflecting prism 19 and a beam expander (not shown) in the same optical path, and the coaxial connecting rod 17 can be configured as four supports, and the convex lens 18 can slide up and down on the four supports. The beam shaping and focusing module 3 further includes an optical connecting rod 20 fixedly connected to the convex lens 18 and a Z-axis displacement stage 21, the Z-axis displacement stage 21 located to the right of the optical connecting rod 20 and connected to the convex lens 18 by the optical connecting rod 20. The Z-axis displacement stage 21 is fixed to the base 7. An adjustment knob 22 located on the lower right side of the Z-axis displacement stage 21 adjusts the position of the optical connecting rod 20 up and down to ensure that the spot when the beam strikes the back of the material being measured is a focused spot. The Z-axis is in the height direction, and a displacement stage with a known height direction can be selected as the Z-axis displacement stage 21; however, a detailed explanation of its specific structure is omitted.

[0046] Furthermore, the apparatus for measuring the thermal diffusivity of the material further includes an analysis module 6, the infrared camera module 5 includes an infrared main unit 9, and the analysis module 6 is connected to the infrared main unit 9. The analysis module 6 receives and processes the thermal image sequence, and the analysis module 6 calculates the thermal diffusivity of the material based on the thermal image sequence, and since the calculation can be performed using known one-dimensional or multi-dimensional heat wave methods, a detailed explanation is omitted.

[0047] Furthermore, a protective fixed frame 1 is provided on the outside of the device for measuring the thermal diffusivity of the material.

[0048] This invention utilizes a drive module to drive an infrared camera module so that it can move freely up and down. The easily focused and freely movable infrared camera module can acquire surface images of materials in a vacuum sample chamber module, and can acquire an image of the thermal diffusivity distribution on the sample surface in a single measurement, which is advantageous for evaluating material defects and uniformity. The lens converter can use various infrared microscope objective lenses, and the infrared camera module drives the infrared microscope objective lens to match various objective lens focal lengths, enabling detection at multiple positions and acquisition of images of multiple materials to be measured.

[0049] Furthermore, the thermal diffusivity measuring device for materials according to the present invention can be applied not only to film materials but also to other types of materials such as lumps, powders, laminates, and pastes, and measurements can be performed by selecting the sample chamber corresponding to the material.

[0050] The above embodiments are not intended to limit the technical means of the present invention, but are merely illustrative. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical means described in the above embodiments or make equivalent substitutions to some of their technical features. Such modifications or substitutions will not cause the essence of the corresponding technical means to deviate from the spirit and scope of the technical means of each embodiment of the present invention. [Explanation of Symbols]

[0051] 1 Fixed frame 2 Modulated laser modules 3. Beam shaping and focusing module 4. Vacuum Sample Chamber Module 5. Infrared camera module 6 Analysis Modules 7 Base 8 fixing hole 9. Infrared Main Unit 10. Infrared microscope objective lens 11 Mobile Modules 12 Drag chain 13 Slide rails 14 Support Frame 15 Sample holder 16 Laser power coupling fiber 17 Coaxial connection rod 18 convex lenses 19 Right-angle reflecting prism 20 Optical connection rods 21 Z-axis displacement stage 22 Adjustment knobs 23 Lasers 24. Lens converter.

Claims

1. It includes a base, a modulation laser module, a beam shaping and focusing module, and a drive module fixed to the base, Above the beam shaping and focusing module, a vacuum sample chamber module is provided where the material is fixed. An infrared camera module that can move vertically is provided above the vacuum sample chamber module. The drive module drives the infrared camera module to move up and down. The modulated laser module emits a laser beam to the beam shaping and focusing module. The beam shaping and focusing module guides the laser beam to the vacuum sample chamber module to irradiate the material. The infrared camera module acquires a thermal image sequence of the material after heating. The beam shaping and focusing module is A coaxial connecting rod extending in the vertical direction, A right-angle reflecting prism fixed to the aforementioned coaxial connecting rod, A convex lens is located above the right-angle reflecting prism and is supported by the coaxial connecting rod so as to be vertically movable, A device for measuring the thermal diffusivity of a material, characterized by the features described above.

2. The drive module includes a motor and a moving module, The motor drives the moving module to move the infrared camera module up and down along a fixed route. A device for measuring the thermal diffusivity of a material as described in feature 1.

3. The aforementioned moving module includes a drag chain and a slide rail, The drag chain is connected to the top of the infrared camera module, The aforementioned slide rail guides the infrared camera module. A device for measuring the thermal diffusivity of a material as described in feature 2.

4. The drive module further includes an operating joystick, The aforementioned operating joystick drives the movement module to move up and down by controlling the motor. A device for measuring the thermal diffusivity of a material as described in feature 2.

5. The infrared camera module includes an infrared main unit and an infrared microscope objective lens. The infrared microscope objective lens is detachably connected to the infrared main unit. The infrared main unit is fixedly connected to the drive module by a support frame. A device for measuring the thermal diffusivity of a material as described in feature 1.

6. The infrared microscope objective lens includes a lens converter. At least one infrared microscope objective lens is attached to the lens converter. The apparatus for measuring the thermal diffusivity of a material according to feature 5.

7. The modulated laser module includes a laser and a power supply, The infrared main unit is connected to the power supply, A device for measuring the thermal diffusivity of a material according to feature 6.

8. The modulated laser module includes a laser, a power supply, and a laser output coupling fiber. The laser power coupling fiber is movably mounted on the base, A device for measuring the thermal diffusivity of a material according to claim 1 or 6.

9. The vacuum sample chamber module includes a vacuum chamber and a bracket that supports the vacuum chamber. The vacuum chamber is connected to a vacuum pump, The vacuum pump evacuates the vacuum chamber, The bracket is provided on the outside of the beam shaping and focusing module. A device for measuring the thermal diffusivity of a material as described in feature 1.

10. A germanium glass lens is placed above the vacuum chamber. A quartz glass lens is provided on the surface of the vacuum chamber facing the beam shaping and focusing module. The vacuum chamber is a vacuum bellows. A device for measuring the thermal diffusivity of a material as described in feature 9.

11. Multiple sample holders are provided within the vacuum chamber. A device for measuring the thermal diffusivity of a material as described in feature 9.

12. The sample holder includes single-hole or multi-hole sample holders of various dimensions. A device for measuring the thermal diffusivity of a material according to feature 11.

13. The sample holder is manufactured from an insulating material for use in high-temperature environments, or from a metal material for use in room-temperature environments. A device for measuring the thermal diffusivity of a material according to the features of 11 or 12.

14. Further includes analysis modules, The infrared camera module includes an infrared main unit, The analysis module is connected to the infrared main unit, The analysis module calculates the thermal diffusivity of the material based on the thermal image sequence. A device for measuring the thermal diffusivity of a material as described in feature 1.

15. The aforementioned infrared main unit uses an area array infrared detector. A device for measuring the thermal diffusivity of a material according to feature 14.

Images