A method of processing a three-dimensional thermal mantle

Abstract

A kind of processing method of three-dimensional heat mantle, using laser to carry out focused line scanning to the front of polyimide film;Potassium hydroxide solution is added dropwise to the front of polyimide film;Polyimide film to which potassium hydroxide solution is added dropwise is subjected to high-temperature crystallization;Crystallization of polyimide film is washed with dilute hydrochloric acid;And clean and dry;The back of polyimide film is scanned using a laser to induce the generation of graphene, obtain a curved heat shield film;Two heat shield films are respectively clamped on the fixed clamp, so that the two heat shield films form a hollow cylinder.By adding potassium hydroxide solution dropwise on polyimide film, it reacts to generate polyimide acid sensitive to water vapor, polyimide film will stretch from curved state to flat state after absorbing moisture;And the graphene on the back of polyimide film can guide the heat flow through the heat shield film to dissipate externally, so as not to affect the electronic components in the center of the heat mantle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat shielding, in particular to a processing method of a three-dimensional heat hood. BACKGROUND

[0002] With the development of society, the functional loss and integration of electronic devices are also constantly improved. The functional loss and integration of electronic devices are improved, and the distribution of heat flow also becomes uneven, which may cause the service life of electronic devices to be shortened, and the reliability during use is greatly reduced. Therefore, effective thermal management of electronic devices is needed, and perfecting the thermal management strategy of electronic devices is particularly important.

[0003] In electronic integrated circuits, due to the thermal effect of current, some electronic components will accumulate too much heat in the range with themselves as the center, causing the local temperature to be too high, and the work of electronic components susceptible to temperature will be affected. For example, the capacitance of electrolytic capacitors will be affected to varying degrees at too high or too low temperatures. The thermal management of electronic devices must have appropriate safety precautions to shield the influence of unstable external temperature, so that electronic components are always in a stable temperature range, which is beneficial to enhance the reliability of electronic components and greatly improve the service life of electronic components, which is very critical in the microelectronics industry. SUMMARY

[0004] In view of the problems in the background art, the purpose of the present application is to provide a processing method of a three-dimensional heat hood, which is used to solve the problem that electronic components are affected by temperature due to the thermal effect of current in electronic integrated circuits, affecting reliability and service life.

[0005] To achieve this purpose, the present application adopts the following technical scheme:

[0006] A processing method of a three-dimensional heat hood, comprising the following steps:

[0007] Step S1, using a laser to perform focused line scanning on the front surface of a polyimide film;

[0008] Step S2, using potassium hydroxide solution to drop onto the front surface of the polyimide film;

[0009] Step S3, high-temperature crystallization of the polyimide film to which the potassium hydroxide solution is added;

[0010] Step S4, using dilute hydrochloric acid to clean the crystallization of the polyimide film; and cleaning and drying the polyimide film;

[0011] Step S5, using a laser to scan the back surface of the polyimide film according to the imported graphene pattern to induce the generation of graphene, and obtain a curved heat shielding film;

[0012] Step S6, the two heat shielding films are respectively clamped on the fixing clamp, so that the two heat shielding films enclose a hollow cylinder, and a three-dimensional heat shield is prepared.

[0013] Preferably, in step S1, the size of the polyimide film is 30mm*45mm*30um;

[0014] The laser is arranged on a Z-direction moving device, an XY moving platform is arranged below the laser, the polyimide film is placed on the XY moving platform, the laser is provided with a CCD camera, and the CCD camera is used for accurately positioning the scanning area of the laser.

[0015] Preferably, in step S1, the laser power of the laser is 6.2W, the laser scanning times of the laser are set to one time, the laser scanning pitch of the laser is 0.08mm, and the laser scanning speed of the laser is 150mm / s.

[0016] Preferably, in step S2, the potassium hydroxide solution with a concentration of 100g / L is spin-coated on the front surface of the polyimide film by using a spin coater, the rotation speed of spin coating is 2500r / min-3200r / min, and the spin coating time is 30s-70s.

[0017] Preferably, in step S3, the crystallization temperature is 70-90℃, and the crystallization time is 10-15min.

[0018] Preferably, in step S4, the crystallized polyimide film is soaked in hydrochloric acid with a concentration of 0.1mol / L, and the soaking time is 5-7min.

[0019] After washing the crystallization on the front surface of the polyimide film, the hydrochloric acid residues on the polyimide film are washed with clean water, and the polyimide film is dried.

[0020] Preferably, in step S5, the required graphene pattern is introduced into the control system of the laser;

[0021] The back surface of the polyimide film is placed on the XY moving platform with the back surface upward, after the laser is positioned and focused on the polyimide film, the laser scans the back surface of the polyimide film according to the introduced pattern.

[0022] Preferably, in step 5, the laser performs two times of laser scanning, and two kinds of graphene with different densities are generated on the back surface of the polyimide film.

[0023] The first laser scanning is applied to a first area of the back surface of the polyimide film, wherein the laser power of the laser is 2.5 W, the laser scanning times of the laser is set to one time, the laser scanning interval of the laser is 0.03 mm, the laser scanning speed of the laser is 300 mm / s, and the laser is defocused downward by 5 mm;

[0024] The second laser scanning is applied to a second area of the back surface of the polyimide film, wherein the laser power of the laser is 7 W, the laser scanning times of the laser is set to one time, the laser scanning interval of the laser is 0.03 mm, the laser scanning speed of the laser is 300 mm / s, and the laser is defocused downward by 5 mm.

[0025] Preferably, the second area is located at the center of the polyimide film, and the first area is located at the periphery of the second area.

[0026] Preferably, in step S6, the fixing clamp comprises a bottom plate and two clamping arms, the two clamping arms are arranged on the top surface of the bottom plate, the two clamping arms are oppositely arranged, and the clamping arms are used for clamping the heat shielding film.

[0027] Compared with the prior art, one of the above technical solutions has the following beneficial effects:

[0028] By dropping potassium hydroxide solution on the polyimide film, polyimide acid sensitive to water vapor is generated, and the polyimide film will relax from the curved state to the flat state after absorbing water; and the graphene on the back surface of the polyimide film can guide the heat flow through the heat shielding film to the outside, so as to not affect the electronic components in the center of the heat tent. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a processing flowchart of a three-dimensional heat tent of the present application;

[0030] Figure 2 is a schematic diagram of a laser processing equipment of the present application;

[0031] Figure 3 is a graphene pattern of a heat shielding film of the present application;

[0032] Figure 4 is a schematic diagram of a fixing clamp of the present application;

[0033] Figure 5 is a structural schematic diagram of a three-dimensional heat tent of the present application (the heat shielding film is in a curved state);

[0034] Figure 6 is a structural schematic diagram of a three-dimensional heat tent of the present application (the heat shielding film is in an unfolded state).

[0035] Wherein: control system 1, laser 2, polyimide film 3, first area graphene 31, second area graphene 32, XY moving platform 4, heat shielding film 5, fixed clamp 6, base plate 61 and clamp arm 62. DETAILED DESCRIPTION

[0036] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components have the same or similar designations throughout the various figures. The embodiments described below are examples of the present application, and are not intended to limit the present application.

[0037] In the description of the present application, it needs to be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0038] In addition, the terms "first", "second" and "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and "third" can explicitly or implicitly include one or more of the features.

[0039] It should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] The technical solutions of the present application are described below in conjunction with the accompanying drawings. Figures 1 to 6 And the technical solutions of the present application are further illustrated by the specific embodiments.

[0041] A processing method of a three-dimensional thermal cloak, comprising the following steps:

[0042] Step S1, using the laser 2 to focus line scanning on the front surface of the polyimide film 3; by using the laser 2 to focus line scanning on the front surface of the imide film 3, the front surface of the polyimide film 3 is modified, and the front and back of the polyimide film 3 is unevenly stressed to present a curved state, and the focused line scanning will not generate laser-induced graphene.

[0043] Step S2, using potassium hydroxide solution drop to the front surface of the polyimide film 3;

[0044] Step S3, the polyimide film 3 to which the potassium hydroxide solution is added is crystallized at high temperature;

[0045] Step S4, using dilute hydrochloric acid to clean the crystallization of the polyimide film 3; and the polyimide film 3 is washed and dried; after the potassium hydroxide solution is added to the surface of the polyimide film 3, the polyimide acid potassium crystal is generated on the surface of the polyimide film 3; the polyimide film 3 generating polyimide acid potassium is soaked in hydrochloric acid, which achieves the effect of cleaning the polyimide acid potassium crystal; after the soaking reaction, the polyimide acid on the surface of the polyimide film 3 which is sensitive to water vapor is generated.

[0046] Step S5, using the laser 2 to scan the back surface of the polyimide film 3 according to the imported graphene pattern to induce the generation of graphene and obtain the heat shielding film 5; by using the laser 2 to scan the back surface of the polyimide film 3, local heating and oxidation reaction are generated on the back surface, which causes the polyimide lattice to vibrate, causing extremely high local temperature (more than 2500℃), which easily breaks the C-O, C=O and N-C bonds, realizes the rearrangement of carbon atoms, and generates laser-induced graphene to obtain the heat shielding film 5.

[0047] Step S6, the two heat shielding films 5 are respectively clamped on the fixed clamp 6, so that the two heat shielding films 5 form a hollow cylinder; since the polyimide film 3 subjected to the focused line scanning is in a curved state, the two curved heat shielding films 5 are clamped on the fixed clamp 6, and the two curved heat shielding films 5 can form a hollow cylinder to constitute a three-dimensional heat cloak (as shown in Figure 5

[0048] The three-dimensional heat cloak prepared by the application is applied to the protection of electronic components which are easily affected by temperature. Specifically, the hollow position of the three-dimensional heat cloak is used to accommodate electronic components. When current passes through the conductor in the integrated circuit, due to the existence of resistance, the electric energy will be converted into heat energy, causing the temperature of the integrated circuit and its surrounding environment to rise. This temperature rise may cause the packaging material of the integrated circuit to release water vapor due to thermal expansion and contraction effect or change of material properties. The water vapor acts on the polyimide acid of the three-dimensional heat cloak (heat shielding film 5), so that the curved heat shielding film 5 is stretched into a horizontal state (as shown in Figure 6 ​At this time, the stretched thermal shielding film 5 can guide the thermal energy to dissipate outward along the graphene structure, so that the thermal energy does not affect the electronic components at the center of the three-dimensional thermal cloak for a long time, thereby achieving protection of the electronic components.

[0049] Further, for electrolytic capacitors, the service life of the electrolytic capacitor is usually 2000 hours in a 105°C environment. The thermal metamaterial can effectively reduce the temperature of the electrolytic capacitor and slow down the capacity decay rate. After using the three-dimensional thermal cloak, the specific service life can be improved by 30%-50%. For power semiconductor elements (such as MOSFET, IGBT), the service life of the power semiconductor element can reach several decades under normal use conditions, but in high-power applications, the power semiconductor element often faces high thermal load, resulting in excessively high junction temperature, thereby affecting the performance and service life of the element. After using the three-dimensional thermal cloak made of thermal metamaterial, the thermal management effect can be significantly improved by optimizing the heat conduction path, reducing the junction temperature of the semiconductor element, and improving the service life by 20%-40%. For pressure sensors, the service life of the pressure sensor may be 5 to 10 years under long-term pressure and temperature changes. After using the three-dimensional thermal cloak made of thermal metamaterial, the service life can be improved by about 20%.

[0050] Further, in step S1, the size of the polyimide film is 30mm x 45mm x 30μm;

[0051] The laser 2 is provided with a Z-direction moving device, and an XY moving platform 4 is arranged below the laser. The polyimide film 3 is placed on the XY moving platform 4. The laser 2 is provided with a CCD camera, which is used for accurate positioning of the scanning area of the laser 2.

[0052] The size of the polyimide film 3 is specified as 30mm x 45mm x 30μm, which helps to ensure that the polyimide film 3 can maintain consistency and predictability in subsequent processing steps, thereby optimizing the performance and quality of the final product. By introducing the Z-direction moving device and the XY moving platform 4, accurate control of the laser 2 in three-dimensional space can be achieved. This high-precision positioning capability is crucial for the laser focusing line scanning step of the laser 2, as it ensures that the laser can accurately act on the predetermined area of the polyimide film 3, thereby achieving uniform modification effect and expected bending state. The laser 2 equipped with a CCD camera can monitor the scanning area in real time, ensuring the accuracy and consistency of laser scanning, which plays an important role in the positioning and focusing of the laser 2.

[0053] Specifically, the polyimide film 3 is laid on a glass sheet (processing carrier), and the glass sheet is placed on the XY moving platform 4, which moves the polyimide film 3 to be focused to the laser 2 (CCD camera) directly below, and the CCD camera feeds back to the control system 1 of the laser according to the information obtained from the polyimide film 3, and controls the Z-direction moving device to drive the laser 2 to move up and down for focusing, so that the laser of the laser 2 can accurately scan on the polyimide film.

[0054] Further, in step S1, the laser power of the laser is 6.2W, the laser scanning times of the laser are set to one time, the laser scanning interval of the laser is 0.08mm, and the laser scanning speed of the laser is 150mm / s.

[0055] By explicitly setting the working parameters of the laser, the modification process of the polyimide film 3 can be accurately controlled. This accuracy helps to ensure that the stress on the front and back of the polyimide film 3 is uniform, thereby obtaining the expected bending state, while avoiding the performance problems caused by excessive modification or insufficient modification.

[0056] Further, in step S2, the uniform coating machine is used to spin coat the potassium hydroxide solution with a concentration of 100g / L on the front surface of the polyimide film, the spin coating speed is 2500r / min-3200r / min, and the spin coating time is 30s-70s.

[0057] The uniform coating machine is used to spin coat the potassium hydroxide solution on the surface of the polyimide film 3 in an atmospheric environment, the spin coating speed is 2500-3200r / min, and the spin coating time is 30-50s. The potassium hydroxide solution is applied by spin coating rather than by direct dropping, in order to uniformly distribute the potassium hydroxide solution on the surface of the polyimide film. The speed and time of the uniform coating machine are controlled mainly to control the film thickness on the polyimide film.

[0058] Preferably, the potassium hydroxide solution with a concentration of 100g / L is dropped on the glass sheet with the polyimide film 3 attached, and the glass sheet is placed in the uniform coating machine for spin coating. Specifically, the corresponding spin coating program is selected on the uniform coating machine, and the speed and time are adjusted to 2000r / min and 50s; the glass sheet with the polyimide film 3 attached is placed on the tray of the uniform coating machine, the potassium hydroxide solution is dropped on the center of the glass sheet using a pipette, the top cover of the uniform coating machine is closed and the vacuum key is pressed, so that the glass sheet is adsorbed on the tray of the uniform coating machine; the uniform coating machine is started to begin spin coating; after spin coating is completed, the vacuum inside the uniform coating machine is released, the top cover of the uniform coating machine is opened, and the glass sheet that has been spin coated is removed.

[0059] Further, in step S3, the crystallization temperature is set to 70-90°C, and the crystallization time is 10-15 minutes.

[0060] Setting the crystallization temperature in the range of 70-90°C can ensure that the material is crystallized at an appropriate temperature, thereby optimizing the crystallization process. This temperature range generally enables the material to achieve the optimal crystallization rate and degree of crystallinity, which helps to improve the quality and performance of the product. Both excessively high and low temperatures can adversely affect the crystallization process of the material. Excessively high temperatures can cause the material to decompose or produce unnecessary side reactions, while excessively low temperatures can make the crystallization process too slow or even lead to incomplete crystallization.

[0061] Setting the crystallization time in the range of 10-15 minutes can ensure that the material has sufficient time to fully crystallize. This helps to form a more complete and compact crystal structure, thereby improving the strength and durability of the product. Reasonable crystallization time not only ensures the quality of the product, but also improves production efficiency. Excessively long crystallization time can lead to prolonged production cycle and increased production cost, while excessively short crystallization time can result in unstable product quality.

[0062] Further, in step S4, the crystallized polyimide film is soaked in hydrochloric acid with a concentration of 0.1 mol / L for 5-7 minutes.

[0063] After washing the crystallized polyimide film on the front side, the remaining hydrochloric acid on the polyimide film is washed with clean water, and the polyimide film is dried.

[0064] Soaking the crystallized polyimide film 3 in hydrochloric acid with a concentration of 0.1 mol / L can effectively remove the polyamide acid potassium crystalline on the surface of the polyimide film 3. These crystalline may affect the performance and appearance of the polyimide film 3, and the soaking treatment with hydrochloric acid can ensure the cleanliness and smoothness of the surface of the polyimide film 3. The soaking time is set to 5-7 minutes, which can ensure sufficient contact and reaction between the hydrochloric acid and the film surface, and avoid unnecessary damage to the film caused by excessive soaking time.

[0065] Washing the remaining hydrochloric acid on the polyimide film 3 with clean water can avoid the influence of hydrochloric acid on the subsequent processing or use of the polyimide film 3, which helps to ensure the quality and stability of the film. Drying the polyimide film 3 can remove the surface moisture and prevent the influence of moisture on the performance of the polyimide film 3. At the same time, drying treatment can also make the polyimide film 3 more stable, improve its durability and service life.

[0066] Further, in step S5, the required graphene pattern is imported into the control system of the laser;

[0067] The back of the polyimide film is placed on the XY moving platform with the back facing up. After the laser is positioned and focused on the polyimide film, the laser performs laser scanning on the back of the polyimide film according to the imported pattern.

[0068] The polyimide film 3 is attached to the glass sheet (processing carrier) with the back facing up, and then the glass sheet is placed on the XY moving platform 4. The CCD camera of the laser 2 is positioned and focused, and the polyimide film 3 is laser scanned according to the pattern signal of the control system 1.

[0069] Further, by importing the required graphene pattern into the control system of the laser, high-precision patterning processing can be achieved. Laser scanning technology can accurately process the polyimide film 3 according to the preset pattern, avoiding errors and irregularities that may be caused by traditional processing methods.

[0070] Further, in step 5, the laser performs two laser scans, and two graphene with different densities are generated on the back of the polyimide film;

[0071] The first laser scan is applied to the first area on the back of the polyimide film, wherein the laser power of the laser is 2.5W, the laser scanning frequency of the laser is set to one time, the laser scanning interval of the laser is 0.03mm, the laser scanning speed of the laser is 300mm / s, and the laser is defocused downward by 5mm;

[0072] The second laser scan is applied to the second area on the back of the polyimide film, wherein the laser power of the laser is 7W, the laser scanning frequency of the laser is set to one time, the laser scanning interval of the laser is 0.03mm, the laser scanning speed of the laser is 300mm / s, and the laser is defocused downward by 5mm.

[0073] Through two laser scans, two graphene with different densities can be generated on the back of the polyimide film 3. Graphene with different densities has different electrical, thermal and mechanical properties. By adjusting the density of graphene, the performance and distribution of graphene in the polyimide film 3 can be optimized, thereby improving the overall performance of the three-dimensional thermal cloak.

[0074] Specifically, after the positioning and focusing of the laser 2 are completed, the processing parameter settings for the first laser scanning of the laser 2 are as follows: the laser power is set to 2.5 W, the laser scanning times are set to 1, the scanning interval is set to 0.03 mm, and the laser scanning speed is set to 300 mm / s, and the laser 2 is defocused downward by 5 mm to avoid excessive power of the laser 2 affecting the processing quality of the sample; after the processing parameter settings are completed, the laser 2 performs laser scanning on the first area on the back of the polyimide film 3 to obtain the first area graphene 31 with a lower thermal conductivity. Then, the processing parameter settings for the second laser scanning of the laser 2 are as follows: the laser power is set to 7 W, the laser scanning times are set to 1, the scanning interval is set to 0.03 mm, and the laser scanning speed is set to 300 mm / s, and the laser 2 is defocused downward by 5 mm; after the processing parameter settings are completed, the laser 2 performs laser scanning on the second area on the back of the polyimide film 3 to obtain the second area graphene 32 with a higher thermal conductivity. Thus, the heat shielding film 5 is obtained.

[0075] Further, the second area is located at the center of the polyimide film 3, and the first area is located at the outer periphery of the second area.

[0076] Since the second area is located at the center of the polyimide film 3 and the high-power laser scanning generates high-density graphene (the second area graphene 32), this area will have a higher thermal conductivity. The high thermal conductivity helps the rapid transfer and diffusion of heat in the central area, thereby improving the thermal response speed and thermal management efficiency of the three-dimensional thermal cloak.

[0077] It is worth noting that among the two types of graphene with different densities generated on the back of the polyimide film 3, the thermal conductivity of the first area is lower, while the thermal conductivity of the laser-induced graphene in the second area located in the central annulus is higher. Such a model is determined based on the theoretical design of heat shielding according to the coordinate transformation thermodynamics theory and the effective medium theory. For the concentric annular pattern in the second area, the obtained heat shielding film 5 has isotropy, which is conducive to more uniform temperature conduction outward.

[0078] Further, in step S6, the fixing clamp 6 includes a bottom plate 61 and two clamp arms 62, the two clamp arms 62 are arranged on the top surface of the bottom plate 61, and the two clamp arms 62 are oppositely arranged, and the clamp arms 62 are used for clamping the heat shielding film 5.

[0079] Through the two oppositely arranged clamp arms 62, precise clamping and positioning of the heat shielding film 5 can be achieved, and the two curved heat shielding films 5 can be enclosed to form a hollow cylinder for accommodating the electrical elements to be protected.

[0080] Preferably, the bottom plate 61 is a 50mm×50mm×10mm cube plate; the clamping arm 62 is composed of two 10mm×50mm rectangular clamping pieces, and the heat shielding film 5 is arranged between the two clamping pieces.

[0081] The present invention is described in more detail below through an embodiment.

[0082] The processing method of the three-dimensional thermal cloak of this embodiment is as follows:

[0083] Step S1:

[0084] Cut a polyimide film 3 of 30mm x 45mm x 30μm and apply it to a glass sheet covered with a blue film using a small roller brush. Use the small roller brush to squeeze out any air between the polyimide film 3 and the glass sheet, ensuring that the polyimide film 3 is completely adhered to the glass sheet. Avoid any bubbles that might affect the surface quality of the laser processing. Place the glass sheet with the polyimide film 3 to be processed on the XY moving platform 4, ensuring a smooth and even processing of the polyimide film 3. Laser 2 captures the position of the polyimide film 3 on the XY moving platform 4 using a CCD camera and transmits this information to control system 1. The XY moving platform 4 then moves along the X and Y axes, ensuring that the polyimide film 3 to be processed is directly below laser 2. Laser 2 is focused by adjusting the Z-axis movement mechanism.

[0085] After adjusting the focal length and accurate positioning, set the processing parameters of laser 2. The specific settings are as follows: the laser power is set to 6.2W, the number of laser scans is set to 1, the scanning interval is set to 0.08mm, and the laser scanning speed is set to 150mm / s. After the processing parameters are set, let the laser 2 focus and line scan the polyimide film 3 (front) to complete the modification of the front of the polyimide film 3, so that the front and back sides of the polyimide film 3 are unevenly stressed and present a curved state.

[0086] Step S2:

[0087] A 100g / L potassium hydroxide solution is dripped onto a glass sheet with a polyimide film 3 attached, and the glass sheet is placed in a spin coater for spin coating. Specifically, the corresponding spin coating program is selected on the spin coater, and the speed and time are adjusted to 2000r / min and 50s respectively. The glass sheet with the polyimide film 3 attached is placed on the spin coater tray. A pipette is used to drip the potassium hydroxide solution onto the center of the glass sheet. The top cover of the spin coater is closed and the vacuum button is pressed to allow the glass sheet to be adsorbed on the spin coater tray. The spin coater is started to begin spin coating. After the spin coating is completed, the vacuum inside the spin coater is removed, the top cover of the spin coater is opened, and the spin-coated glass sheet is removed.

[0088] Step S3:

[0089] The glass sheet with the polyimide film 3 attached after spin coating is placed on the heating table, the temperature of the heating table is set, and the glass sheet is heated at a temperature of 70-90°C for 10-15 min until white crystals appear on the surface of the polyimide film 3, and then the heated glass sheet is removed.

[0090] Step S4:

[0091] 150 mL of 0.1 mol / L hydrochloric acid is poured into a beaker, and then the heated glass sheet with the polyimide film 3 attached is placed in the 0.1 mol / L hydrochloric acid, and the sample is soaked at room temperature for 5-7 min to wash away the white crystals on the sample. After washing, the sample is taken out, the residual hydrochloric acid on the sample is washed with clean water, and the sample is dried on the heating table.

[0092] Step S5:

[0093] Referring to Figure 3 The graphene pattern of the heat shielding film 5 is imported into the control system 1 of the laser.

[0094] The dried polyimide film 3 is carefully peeled off from the glass sheet, and then the polyimide film 3 is flipped over and reattached to the glass sheet. Then the positioning and focusing steps in step S1 are repeated. After positioning and focusing are completed, the laser 2 is set with processing parameters for the first laser scanning, and the specific settings are as follows: the laser power is set to 2.5 W, the laser scanning times are set to 1, the scanning interval is set to 0.03 mm, and the laser scanning speed is set to 300 mm / s. The laser 2 is defocused downward by 5 mm to avoid excessive power of the laser 2 affecting the processing quality of the sample. After the processing parameters are set, the laser 2 performs laser scanning on the first area on the back of the polyimide film 3 to obtain the first area graphene 31 with lower thermal conductivity. Then the laser 2 is set with processing parameters for the second laser scanning, and the specific settings are as follows: the laser power is set to 7 W, the laser scanning times are set to 1, the scanning interval is set to 0.03 mm, and the laser scanning speed is set to 300 mm / s. The laser 2 is defocused downward by 5 mm. After the processing parameters are set, the laser 2 performs laser scanning on the second area on the back of the polyimide film 3 to obtain the second area graphene 32 with higher thermal conductivity. Thus, the heat shielding film 5 is obtained.

[0095] Step S6:

[0096] Referring to Figure 5 The two heat shielding films 5 processed with the same parameters and the same steps are clamped in the fixing clamp 6 to form a hollow cylinder, and a three-dimensional heat cloak is obtained.

[0097] The technical principles of the present application are described above in combination with specific embodiments. These descriptions are only for explaining the principles of the present application, and cannot be interpreted as limiting the protection scope of the present application in any way. Based on the explanations herein, other specific embodiments of the present application can be conceived by those skilled in the art without any creative effort, and these embodiments will all fall within the protection scope of the present application.

Claims

1. A method for processing a three-dimensional thermal cloak, characterized in that: The following steps are involved: Step S1, using a laser to perform focused line scanning on the front surface of the polyimide film; Step S2: adding a potassium hydroxide solution dropwise to the front surface of the polyimide film; Step S3, performing high-temperature crystallization on the polyimide film to which potassium hydroxide solution is added; Step S4: using dilute hydrochloric acid to clean the crystals of the polyimide film; and then cleaning and drying the polyimide film; Step S5: using a laser to perform two laser scans on the back of the polyimide film according to the introduced graphene pattern, thereby inducing the generation of two graphenes with different densities on the back of the polyimide film, thereby obtaining a curved heat shielding film; The first laser scan is applied to the first area on the back side of the polyimide film, wherein the laser power of the laser is 2.5 W, the number of laser scans of the laser is set to one, the laser scanning pitch of the laser is 0.03 mm, the laser scanning speed of the laser is 300 mm / s, and the laser is defocused downward by 5 mm; The second laser scan is applied to the second area on the back side of the polyimide film, wherein the laser power of the laser is 7 W, the number of laser scans of the laser is set to one, the laser scanning pitch of the laser is 0.03 mm, the laser scanning speed of the laser is 300 mm / s, and the laser is defocused downward by 5 mm; Step S6: clamp the two heat shielding films on the fixing fixtures respectively, so that the two heat shielding films are enclosed to form a hollow cylinder, thereby obtaining a three-dimensional heat cloak.

2. The method for processing a three-dimensional thermal cloak according to claim 1, characterized in that: In step S1, the size of the polyimide film is 30 mm × 45 mm × 30 μm; The laser is arranged on a Z-direction moving device, an XY moving platform is arranged below the laser, the polyimide film is placed on the XY moving platform, and the laser is provided with a CCD camera, which is used to accurately locate the scanning area of ​​the laser.

3. The method for processing a three-dimensional thermal cloak according to claim 2, characterized in that: In step S1 , the laser power of the laser is 6.2 W, the number of laser scans of the laser is set to once, the laser scanning pitch of the laser is 0.08 mm, and the laser scanning speed of the laser is 150 mm / s.

4. The method for processing a three-dimensional thermal cloak according to claim 1, characterized in that: In step S2, a spin coater is used to spin-coat the potassium hydroxide solution with a concentration of 100 g / L onto the front surface of the polyimide film. The spin-coating speed is 2500 r / min-3200 r / min, and the spin-coating time is 30 s-70 s.

5. The method for processing a three-dimensional thermal cloak according to claim 1, characterized in that: In step S3, the crystallization temperature is 70° C.-90° C., and the crystallization time is 10 min-15 min.

6. The method for processing a three-dimensional thermal cloak according to claim 1, characterized in that: In step S4, the crystallized polyimide film is soaked in hydrochloric acid with a concentration of 0.1 mol / L for 5 to 7 minutes; After cleaning the crystals on the front side of the polyimide film, the hydrochloric acid residue on the polyimide film is washed off with clean water, and the polyimide film is dried.

7. The method for processing a three-dimensional thermal cloak according to claim 3, characterized in that: In step S5, the desired graphene pattern is introduced into the control system of the laser; The back side of the polyimide film is placed on the XY moving platform, and after the laser positions and focuses the polyimide film, the laser scans the back side of the polyimide film according to the introduced pattern.

8. The method for processing a three-dimensional thermal cloak according to claim 7, characterized in that: The second region is located at the center of the polyimide film, and the first region is located at the periphery of the second region.

9. The method for manufacturing a three-dimensional thermal cloak according to claim 1, characterized in that: In step S6, the fixing fixture includes a bottom plate and two clamping arms, wherein the two clamping arms are provided on the top surface of the bottom plate and are arranged opposite to each other, and the clamping arms are used to clamp the heat shielding film.

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