Terahertz wave band liquid crystal device preparation method based on additive manufacturing technology

Abstract

The invention discloses a terahertz wave band liquid crystal device preparation method based on an additive manufacturing technology, and relates to the field of liquid crystal preparation, and the terahertz wave band liquid crystal device preparation method comprises the following steps: carrying out modeling through SolidWorks to obtain an upper substrate model and a lower substrate model; printing the upper substrate model and the lower substrate model to obtain an upper resin substrate and a lower resin substrate; detecting the upper resin substrate and the lower resin substrate, and cleaning the upper resin substrate and the lower resin substrate; spin-coating transparent electrode layers on the surfaces of the upper resin substrate and the lower resin substrate; the edges of the upper resin substrate and the lower resin substrate are externally connected with silver wire electrodes; spin-coating orientation layers on the surfaces of the upper resin substrate and the lower resin substrate, and rubbing the orientation layers; splicing the resin upper substrate and the resin lower substrate to obtain a resin box; liquid crystal is poured into the resin box, the resin box is sealed, and the liquid crystal device is obtained; efficient, low-cost and integrated manufacturing of the terahertz liquid crystal device is achieved, and the terahertz liquid crystal device has higher design flexibility.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal preparation, and particularly to a method for preparing a terahertz band liquid crystal device based on additive manufacturing technology. Background Art

[0002] Terahertz wave THz refers to an electromagnetic wave with a frequency between 0.1 THz and 10 THz, which lies between microwaves and infrared light. In recent years, terahertz technology has shown great application potential in fields such as imaging, communication, and sensing. However, the development of terahertz devices still faces many challenges, and one of the key challenges is the lack of efficient, low-cost, and easy-to-process terahertz functional materials.

[0003] As a tunable medium, liquid crystal materials have been widely used in the visible light and microwave bands. In recent years, researchers have begun to explore the application potential of liquid crystal materials in the terahertz band. Traditional terahertz liquid crystal devices usually use quartz or silicon as the substrate material, and use techniques such as photolithography and spin coating to prepare transparent electrodes and alignment layers.

[0004] However, although quartz or silicon substrates have high terahertz transmittance and surface flatness, they also have some limitations. First, quartz or silicon substrates are hard and brittle materials, making it difficult to realize the design of non-planar or complex three-dimensional structures, and they are prone to damage under complex environments or mechanical stresses, which limits the adaptability of terahertz liquid crystal devices in special application scenarios. Second, the processing of quartz or silicon substrates relies on micro-nano processing techniques such as photolithography and etching, which are expensive in equipment and cumbersome in process steps, making it difficult to achieve low-cost and rapid manufacturing. Finally, when preparing a sandwich structure, it is necessary to accurately align and bond multiple layers of materials together, and the high hardness and low toughness of quartz wafers make the alignment and bonding process difficult.

[0005] Therefore, a method for preparing a terahertz band liquid crystal device based on additive manufacturing technology is provided to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a terahertz band liquid crystal device based on additive manufacturing technology, which combines traditional liquid crystal device preparation processes to achieve efficient, low-cost, and integrated manufacturing of terahertz liquid crystal devices, while improving the flexibility of design.

[0007] To achieve the above purpose, the present invention provides a method for preparing a terahertz band liquid crystal device based on additive manufacturing technology, including the following steps: S1: Modeling through SolidWorks to obtain an upper substrate model and a lower substrate model; S2: Printing the upper substrate model and the lower substrate model to obtain a resin upper substrate and a resin lower substrate; S3: Detect the upper resin substrate and the lower resin substrate, and clean the upper resin substrate and the lower resin substrate; S4: Spin-coat a transparent electrode layer on the surfaces of the upper resin substrate and the lower resin substrate; S5: Connect silver wire electrodes to the edges of the upper resin substrate and the lower resin substrate; S6: Spin-coat an alignment layer on the surfaces of the upper resin substrate and the lower resin substrate, and perform rubbing treatment on the alignment layer; S7: Join the upper resin substrate and the lower resin substrate to obtain a resin cell; S8: Pour liquid crystal into the resin cell, seal the resin cell, and obtain a liquid crystal device.

[0008] Preferably, in step S1, the sizes of the upper substrate model and the lower substrate model are both set to 2 cm × 2 cm × 1 mm. Four cylindrical holes are provided on the upper substrate model, and four columnar bodies corresponding to the cylindrical holes are provided on the lower substrate model. Bold fonts are provided between the four columnar bodies and the lower substrate model, and the size of the bold font is set to 2 mm × 2 mm × 0.31 mm.

[0009] Preferably, step S2 specifically includes the following steps: S21: Export the upper substrate model and the lower substrate model as.stl files; S22: Perform slicing on the.stl files through the software of the printer to obtain slice files; S23: Import the slice files into the printer for printing to obtain the upper resin substrate and the lower resin substrate.

[0010] Preferably, step S3 specifically includes the following steps: S31: Soak the upper resin substrate and the lower resin substrate with isopropyl alcohol. After the uncured resin is dissolved, take out the upper resin substrate and the lower resin substrate; S32: Detect the quality of the upper resin substrate and the lower resin substrate, and select the upper resin substrate and the lower resin substrate with high surface flatness, no texture, and no model defects; S33: Ultrasonically clean the upper resin substrate and the lower resin substrate with deionized water, ethanol, and isopropyl alcohol respectively. The cleaning time is set to 10 minutes. After cleaning, dry the upper resin substrate and the lower resin substrate with nitrogen, and store the upper resin substrate and the lower resin substrate away from dust.

[0011] Preferably, step S4 specifically includes the following steps: S41: Spin-coat a transparent electrode layer on the surfaces of the upper resin substrate and the lower resin substrate through a spin coater. The transparent electrode layer is set as a mixed solution of DMSO and PEDOT:PSS. The rotation speed of the spin coater is set to 2000 - 4000 revolutions per minute, and the spin coating time is set to 40 - 60 seconds; S42: Heat the transparent electrode layer using a heating stage. Set the temperature of the heating stage to 80 - 100 °C and the heating time to 10 minutes.

[0012] Preferably, step S5 specifically includes the following steps: S51: Coat a long strip of silver paste on the edges of the upper resin substrate and the lower resin substrate, and insert a silver wire into the long strip of silver paste; S52: Heat the long strip of silver paste using a heating stage. Set the temperature of the heating stage to 90 °C and the heating time to 10 - 20 minutes.

[0013] Preferably, step S6 specifically includes the following steps: S61: Spin - coat an alignment layer on the surfaces of the upper resin substrate and the lower resin substrate. The alignment layer is set as a 6.0% DL - 2194 low - temperature curing TN - type liquid crystal alignment agent; S62: Heat the alignment layer using a heating stage for the first and second times. Set the temperature for the first heating to 80 - 90 °C and the first heating time to 30 minutes. Set the temperature for the second heating to 100 - 120 °C and the second heating time to 1.5 hours; S63: Rub the alignment layer using a flannel cloth. The rubbing direction of the alignment layer on the upper resin substrate is opposite and parallel to the rubbing direction of the alignment layer on the lower resin substrate.

[0014] Preferably, step S7 specifically includes the following steps: S71: Fix and connect the upper resin substrate and the lower resin substrate through a cylindrical hole and a column body, and add a Teflon gasket at the edge of the gap; S72: Seal three sides of the upper resin substrate and the lower resin substrate using AB glue to obtain a resin cell.

[0015] Preferably, step S8 specifically includes the following steps: S81: Infuse liquid crystal into the unsealed side of the resin cell. The liquid crystal is set as the TN - type mixed liquid crystal HYJYLC3A400 - 300; S82: Heat the liquid crystal using a heating stage. Set the temperature of the heating stage to 100 °C and the heating time to 1 - 2 hours; S83: Cool the liquid crystal to room temperature, and seal the unsealed side of the resin cell using AB glue to obtain a liquid crystal device.

[0016] Therefore, by adopting the above - mentioned method for preparing a terahertz - band liquid crystal device based on additive manufacturing technology, the present invention has the following beneficial effects: (1) The 3D printing design of the present invention is flexible, capable of manufacturing liquid crystal devices with more complex structures, and expanding the application scenarios of liquid crystal devices; (2) The high-temperature resistant resin selected in the present invention can avoid the high-temperature damage caused in the subsequent box-making process to a certain extent, and it has certain hydrophilicity, which is convenient for the spin coating of the subsequent mixed solution. (3) By designing the mortise and tenon structure, the present invention can reduce the addition of thickness-maintaining components such as spacers or gaskets, reduce the operation difficulty of the box-making steps, and simplify the preparation process of the liquid crystal cell. (4) By fabricating the resin substrate through 3D printing and combining with the traditional liquid crystal device preparation process, the present invention realizes the preparation of a novel terahertz liquid crystal device, and has the advantages of low cost and high plasticity of the substrate.

[0017] The method solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0018] Figure 1 It is a structural diagram of the upper substrate model and the lower substrate model in the embodiment of the present invention. Figure 2 It is a top view of the upper substrate model and the lower substrate model in the embodiment of the present invention. Figure 3 It is a side view of the upper substrate model and the lower substrate model in the embodiment of the present invention. Figure 4 It is a terahertz time-domain spectrogram of the liquid crystal device in the embodiment of the present invention. Figure 5 It is a voltage-phase modulation diagram of the liquid crystal device in the embodiment of the present invention.

[0019] Wherein: 1. Upper substrate model; 2. Lower substrate model; 3. Cylindrical hole; 4. Column body; 5. Bold font. Specific Embodiments

[0020] The method solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the method terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention belongs.

[0022] In the present invention, words such as "including" or "comprising" mean that the elements before this word cover the elements listed after this word, and do not exclude the possibility of also covering other elements. The orientation or positional relationship indicated by terms such as "inside", "outside", "above", "below", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In the present invention, unless otherwise clearly specified and defined, terms such as "attachment" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Embodiment As Figures 1-3 shown, the present invention provides a preparation method of a terahertz-band liquid crystal device based on additive manufacturing technology, including the following steps: S1: Modeling is carried out through SolidWorks to obtain an upper substrate model and a lower substrate model; In step S1, the sizes of the upper substrate model 1 and the lower substrate model 2 are both set to 2 cm × 2 cm × 1 mm, and the sizes of the upper substrate model 1 and the lower substrate model 2 can be adjusted according to actual needs; Four cylindrical holes 3 are provided on the upper substrate model 1, and four columnar bodies 4 corresponding to the cylindrical holes 3 are provided on the lower substrate model 2. Reinforced bodies 5 are provided between the four columnar bodies 4 and the lower substrate model 2, and the size of the reinforced body 5 is set to 2 mm × 2 mm × 0.31 mm.

[0024] The upper substrate model 1 and the lower substrate model 2 can be spliced together through the tenon and mortise structure composed of the cylindrical holes 3 and the columnar bodies 4, which reduces the difficulty of the final sealing step of the liquid crystal device. At the same time, a gap for pouring liquid crystal is left in the middle, and the height of the reinforced body 5 can be adjusted according to actual needs to adjust the thickness of the gap.

[0025] S2: Print the upper substrate model and the lower substrate model to obtain a resin upper substrate and a resin lower substrate; Step S2 specifically includes the following steps: S21: Export the upper substrate model and the lower substrate model in the form of a.stl file; S22: Slice the.stl file through the printer software to obtain a sliced file. During the slicing process, default parameters can be used, or the parameters can be adjusted according to the type of resin. S23: Import the sliced file into the printer for printing to obtain the resin upper substrate and the resin lower substrate.

[0026] Combining 3D printing technology with the traditional liquid crystal device manufacturing process realizes a new method for manufacturing terahertz liquid crystal devices.

[0027] S3: Detect the resin upper substrate and the resin lower substrate, and clean the resin upper substrate and the resin lower substrate. Step S3 specifically includes the following steps: S31: Immerse the resin upper substrate and the resin lower substrate in isopropyl alcohol. After the uncured resin is dissolved, take out the resin upper substrate and the resin lower substrate. S32: Detect the quality of the resin upper substrate and the resin lower substrate, and select the resin upper substrate and the resin lower substrate with high surface flatness, no texture, and no model defects for the subsequent liquid crystal device manufacturing steps. S33: Ultrasonically clean the resin upper substrate and the resin lower substrate with deionized water, ethanol, and isopropyl alcohol respectively. Set the cleaning time to 10 minutes. After cleaning, dry the resin upper substrate and the resin lower substrate with nitrogen, and store the resin upper substrate and the resin lower substrate away from dust to ensure the cleanliness of the surfaces of the resin upper substrate and the resin lower substrate.

[0028] S4: Spin-coat a transparent electrode layer on the surfaces of the resin upper substrate and the resin lower substrate. Step S4 specifically includes the following steps: S41: Spin-coat a transparent electrode layer on the surfaces of the resin upper substrate and the resin lower substrate through a spin coater. The transparent electrode layer is set as a mixed solution of DMSO and PEDOT:PSS. Set the rotation speed of the spin coater to 2000 - 4000 revolutions per minute, and set the spin-coating time to 40 - 60 seconds. S42: Heat the transparent electrode layer through a heating stage. Set the temperature of the heating stage to 80 - 100 °C, and set the heating time to 10 minutes to cure the mixed solution of DMSO and PEDOT:PSS.

[0029] S5: Connect silver wire electrodes externally to the edges of the resin upper substrate and the resin lower substrate. Step S5 specifically includes the following steps: S51: Coat a long strip of silver paste on the edges of the resin upper substrate and the resin lower substrate. The width of the long strip of silver paste should be appropriate and should not cover the cylindrical holes and the columns. Insert a silver wire of appropriate length into the long strip of silver paste as an external electrode. S52: Heat the long strip of silver paste using a heating stage. Set the temperature of the heating stage to 90 °C and the heating time to 10 - 20 minutes to cure the long strip of silver paste.

[0030] S6: Spin-coat an alignment layer on the surfaces of the upper resin substrate and the lower resin substrate, and perform a rubbing treatment on the alignment layer; Step S6 specifically includes the following steps: S61: Spin-coat an alignment layer on the surfaces of the upper resin substrate and the lower resin substrate. To avoid damaging the upper resin substrate and the lower resin substrate at high temperatures, the alignment layer is set to a 6.0% DL-2194 low-temperature curing TN-type liquid crystal aligning agent; S62: Perform the first heating and the second heating on the alignment layer using a heating stage. Set the temperature of the first heating to 80 - 90 °C and the first heating time to 30 minutes. Set the temperature of the second heating to 100 - 120 °C and the second heating time to 1.5 hours; S63: Rub the alignment layer using a flannel cloth. The rubbing direction of the alignment layer on the upper resin substrate is opposite and parallel to the rubbing direction of the alignment layer on the lower resin substrate.

[0031] S7: Join the upper resin substrate and the lower resin substrate to obtain a resin cell; Step S7 specifically includes the following steps: S71: Fix and connect the upper resin substrate and the lower resin substrate through a cylindrical hole and a columnar body. During the joining process, the long strip of silver paste on the upper resin substrate and the long strip of silver paste on the lower resin substrate need to be staggered and not electrically connected. Add a bar-shaped Teflon gasket of appropriate size at the edge of the gap; S72: Seal three sides of the upper resin substrate and the lower resin substrate using AB glue to obtain a resin cell.

[0032] S8: Pour liquid crystal into the resin cell and seal the resin cell to obtain a liquid crystal device.

[0033] Step S8 specifically includes the following steps: S81: Pour liquid crystal into the unsealed side of the resin cell. Set the pouring tool to a syringe, and set the pouring method to pour with the syringe needle close to the edge to avoid air entering the resin cell. The liquid crystal is set to TN-type mixed liquid crystal HYJYLC3A400-300; S82: Heat the liquid crystal using a heating stage. To avoid damaging the upper resin substrate and the lower resin substrate at high temperatures, set the temperature of the heating stage to 100 °C and the heating time to 1 - 2 hours; S83: Cool the liquid crystal to room temperature, seal the unsealed side of the resin cell using AB glue, and let it stand for the glue to cure to obtain a liquid crystal device.

[0034] The liquid crystal device is tested using a terahertz time-domain spectroscopy test system and analyzed through a MATLAB program to obtain a data graph. As Figure 4 shown, the liquid crystal device has a phase modulation effect. When the low voltage is 6.16V, the signal is on the far right. As the voltage increases in the range of 15 - 20V, the signal gradually moves towards the air signal side. The overall terahertz wave transmittance is about 20%. Reducing the thickness of the upper and lower resin substrates can effectively improve the terahertz transmittance. However, it should also be considered that too thin a resin will soften under high-temperature heating, which is not conducive to the subsequent spin-coating process. As Figure 5 shown, the phase modulation amount of the liquid crystal device for terahertz waves of different frequencies changes with voltage. For example, the maximum modulation amount at 0.5THz can reach 98°, and the driving voltage is less than 25V.

[0035] Therefore, the present invention adopts the above-mentioned method for preparing a terahertz-band liquid crystal device based on additive manufacturing technology. Using a 3D printing resin material with high temperature resistance and hydrophilicity as the substrate and combining with the traditional liquid crystal device preparation process, it realizes the efficient, low-cost, and integrated manufacturing of terahertz liquid crystal devices, and has higher design flexibility, providing a new idea and method for the development of terahertz liquid crystal devices, and having important scientific significance and application value.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the method of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the method of the present invention, and these modifications or equivalent replacements cannot make the modified method deviate from the spirit and scope of the method of the present invention.

Claims

1. A preparation method of a terahertz-band liquid crystal device based on additive manufacturing technology, characterized in that, It includes the following steps: S1: Model by SolidWorks to obtain the upper substrate model and the lower substrate model; S2: Print the upper substrate model and the lower substrate model to obtain the resin upper substrate and the resin lower substrate; S3: Detect the resin upper substrate and the resin lower substrate, and clean the resin upper substrate and the resin lower substrate; S4: Spin-coat a transparent electrode layer on the surfaces of the resin upper substrate and the resin lower substrate; S5: Connect silver wire electrodes to the edges of the resin upper substrate and the resin lower substrate; S6: Spin-coat an alignment layer on the surfaces of the resin upper substrate and the resin lower substrate, and perform rubbing treatment on the alignment layer; S7: Splice the resin upper substrate and the resin lower substrate to obtain a resin cell; S8: Pour liquid crystal into the resin cell, seal the resin cell, and obtain a liquid crystal device.

2. The preparation method of a terahertz band liquid crystal device based on additive manufacturing technology according to claim 1, wherein In step S1, the sizes of both the upper substrate model and the lower substrate model are set to 2 cm × 2 cm × 1 mm. Four cylindrical holes are provided on the upper substrate model, and four upright columns corresponding to the cylindrical holes are provided on the lower substrate model. Bold parts are provided between the four upright columns and the lower substrate model, and the size of the bold part is set to 2 mm × 2 mm × 0.31 mm.

3. A method for preparing a terahertz-band liquid crystal device based on additive manufacturing technology according to claim 1, characterized in that Step S2 specifically includes the following steps: S21: Export the upper substrate model and the lower substrate model as.stl files; S22: Perform slicing on the.stl files through the software of the printer to obtain sliced files; S23: Import the sliced files into the printer for printing to obtain the resin upper substrate and the resin lower substrate.

4. A method for preparing a terahertz band liquid crystal device based on additive manufacturing technology according to claim 1, characterized in that Step S3 specifically includes the following steps: S31: Immerse the resin upper substrate and the resin lower substrate in isopropyl alcohol. After the uncured resin is dissolved, take out the resin upper substrate and the resin lower substrate; S32: Detect the quality of the resin upper substrate and the resin lower substrate, and select the resin upper substrate and the resin lower substrate with high surface flatness, no texture, and no model defects; S33: Ultrasonically clean the resin upper substrate and the resin lower substrate with deionized water, ethanol, and isopropyl alcohol respectively. The cleaning time is set to 10 minutes. After cleaning, blow dry the resin upper substrate and the resin lower substrate with nitrogen, and store the resin upper substrate and the resin lower substrate to avoid dust.

5. A method for preparing a terahertz-band liquid crystal device based on additive manufacturing technology according to claim 1, characterized in that, Step S4 specifically includes the following steps: S41: Spin-coat a transparent electrode layer on the surfaces of the resin upper substrate and the resin lower substrate through a spin coater. The transparent electrode layer is set as a mixed solution of DMSO and PEDOT:PSS. The rotation speed of the spin coater is set to 2000 - 4000 revolutions per minute, and the spin-coating time is set to 40 - 60 seconds; S42: Heat the transparent electrode layer through a heating table. The temperature of the heating table is set to 80 - 100 °C, and the heating time is set to 10 minutes.

6. The preparation method of a terahertz band liquid crystal device based on additive manufacturing technology according to claim 1, wherein Step S5 specifically includes the following steps: S51: Coat long silver paste on the edges of the resin upper substrate and the resin lower substrate, and insert silver wires into the long silver paste; S52: Heat the long silver paste through a heating table. The temperature of the heating table is set to 90 °C, and the heating time is set to 10 - 20 minutes.

7. A method for preparing a terahertz band liquid crystal device based on additive manufacturing technology according to claim 1, characterized in that Step S6 specifically includes the following steps: S61: Spin-coat an alignment layer on the surfaces of the resin upper substrate and the resin lower substrate. The alignment layer is set as a 6.0% DL-2194 low-temperature curing TN-type liquid crystal aligning agent; S62: The alignment layer is heated for the first time and the second time through a heating stage. The temperature for the first heating is set to 80 - 90 °C, the time for the first heating is set to 30 minutes, the temperature for the second heating is set to 100 - 120 °C, and the time for the second heating is set to 1.5 hours; S63: The alignment layer is rubbed through a flannelette. The rubbing direction of the alignment layer on the upper resin substrate is opposite and parallel to that of the alignment layer on the lower resin substrate.

8. The method for preparing a terahertz-band liquid crystal device based on additive manufacturing technology according to claim 2, wherein, Step S7 specifically includes the following steps: S71: The upper resin substrate and the lower resin substrate are fixedly connected through a cylindrical hole and a column body, and a Teflon gasket is added at the edge of the gap; S72: The upper resin substrate and the lower resin substrate are sealed on three sides with AB glue to obtain a resin box.

9. A method for preparing a terahertz-band liquid crystal device based on additive manufacturing technology according to claim 1, wherein, Step S8 specifically includes the following steps: S81: Liquid crystal is poured into the unsealed side of the resin box. The liquid crystal is set as the TN - type mixed liquid crystal HYJYLC3A400 - 300; S82: The liquid crystal is heated through a heating stage. The temperature of the heating stage is set to 100 °C, and the heating time is set to 1 - 2 hours; S83: The liquid crystal is cooled to room temperature, and the unsealed side of the resin box is sealed with AB glue to obtain a liquid crystal device.

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