Thin-line-width polymer dispersed liquid crystal (PDLC) film and laser processing method and device thereof

Abstract

The invention provides a thin-line-width PDLC (polymer dispersed liquid crystal) film and a laser processing method and device thereof, and the laser processing method comprises the following steps: S1, flatly placing the PDLC film on a vacuum adsorption platform; and S2, a femtosecond laser is adopted to emit laser, a laser light path is adjusted, the laser penetrates through the PET layer on the surface of the PDLC film and is focused on the ITO layer close to the PET layer, and laser etching scribing is carried out on the ITO layer according to a preset path. According to the method, high-energy and high-precision ultra-short pulse femtosecond laser is focused on the ITO layer in the PDLC film for etching and scribing, the scribing width can reach 20 microns or below, the scribing precision is improved, possibility is provided for partition control and high-precision optical performance of the PDLC film, higher image resolution and definition can be achieved, and the method is suitable for large-scale popularization and application. And more complex patterns or circuits can be carved in the same area, so that the material utilization rate is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of PDLC film processing, and in particular relates to a thin-line width PDLC film and a laser processing method and device thereof. Background Art

[0002] As a material with unique optical properties, PDLC film (polymer dispersed liquid crystal) has shown broad application prospects in the fields of smart windows, projection displays, optical switches, etc. The emergence of the PDLC film laser scribing patent provides an innovative solution for the precise processing and performance optimization of this material. Figure 1 As shown in the figure, the basic structure of PDLC film usually includes liquid crystal layer, conductive layer (ITO), and substrate (PET). The liquid crystal layer is mainly composed of liquid crystal molecules and is the core part of the PDLC film. The arrangement direction of the liquid crystal molecules can be controlled by applying an electric field, thereby changing the optical properties of the film; the conductive layer provides an electric field for the liquid crystal molecules, thereby controlling the arrangement direction of the liquid crystal molecules; the substrate provides support and protection for the PDLC film.

[0003] The thinner line width of the PDLC film can reduce light scattering and diffraction, enhance the directional transmission of light, improve the contrast and brightness uniformity of the image, thereby achieving higher image resolution and clarity, making the pattern or information displayed on the PDLC film more delicate and realistic, improving the visual effect and display quality; and the thin line width is conducive to improving the space utilization of the PDLC film. In the same area, more and more complex patterns or lines can be engraved, thereby increasing the functionality and application range of the PDLC film. Therefore, the thinner the line width of the PDLC film, the more conducive it is to improving its performance and application value. However, the existing PDLC film scribing process is mainly based on long pulse width laser processing, and its scribing width is greater than 50μm. Summary of the invention

[0004] The purpose of the present invention is to provide a laser processing method for a thin line width PDLC film, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A laser processing method for a thin line width PDLC film comprises the following steps:

[0007] S1. Place the PDLC film flat on a vacuum adsorption platform;

[0008] S2. Use a femtosecond laser to emit laser and adjust the laser light path so that the laser is focused on the ITO layer close to the PET layer through the PET layer on the surface of the PDLC film, and laser etching and marking are performed on the ITO layer according to a preset path.

[0009] Furthermore, the laser wavelength emitted by the femtosecond laser is 300-400nm, the laser pulse width is less than 1000fs, the laser frequency is 100-2000KHz, the laser energy is 0.8-1.2μJ, and the scanning speed is 50-200mm / s.

[0010] Furthermore, the laser focused spot is located inside the ITO layer and at a distance of 0.1 to 0.15 mm from the upper / lower surface of the ITO layer.

[0011] Furthermore, the laser focusing spot diameter is 5 to 20 μm.

[0012] Furthermore, the line width of the line etched by the laser on the ITO layer inside the PDLC film is less than 20 μm.

[0013] Furthermore, the temperature of the vacuum adsorption platform is controlled within the phase transition temperature range of the liquid crystal material of the liquid crystal layer inside the PDLC film.

[0014] Furthermore, the surface level error of the PDLC film on the vacuum adsorption platform is less than 20 μm.

[0015] In addition, the present invention also provides a thin-line width PDLC film, which adopts the above-mentioned laser processing method system of the thin-line width PDLC film.

[0016] The present invention also provides a laser processing device for a fine-line width PDLC film, comprising a femtosecond laser, an optical path adjustment component, and a vacuum adsorption platform for adsorbing and fixing the PDLC film. The laser beam emitted by the femtosecond laser passes through the optical path adjustment component and is focused on the PDLC film on the vacuum adsorption platform.

[0017] Furthermore, the optical path adjustment component includes a 45° reflector 1, an adjustable beam expansion and collimation unit, a 45° reflector 2, an aperture, a 45° reflector 3, a galvanometer scanning unit and a focusing lens which are sequentially arranged along the laser optical path.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses a high-energy, high-precision ultrashort pulse femtosecond laser to focus on the ITO layer inside the PDLC film to perform etching and marking. The width of the marking can reach less than 20 μm, which improves the marking accuracy, provides the possibility for the partition control and high-precision optical performance of the PDLC film, and can achieve higher image resolution and clarity. More and more complex patterns or circuits can be engraved in the same area, thereby improving material utilization.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the PDLC film in the present invention;

[0022] Figure 2 Schematic diagram of a laser processing device for a fine line width PDLC film in an embodiment of the present invention.

[0023] Explanation of the reference numerals: 1. PET layer; 2. ITO layer; 3. Liquid crystal layer; 4. Femtosecond laser; 5. 45° reflector one; 6. Adjustable beam expansion and collimation unit; 7. 45° reflector two; 8. Aperture; 9. 45° reflector three; 10. Galvanometer scanning unit; 11. Focusing lens; 12. Vacuum adsorption platform. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are 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, and therefore cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0028] Embodiment 1:

[0029] This embodiment provides a laser processing method for a thin line width PDLC film, comprising the following steps:

[0030] S1. Place the PDLC film flat on a vacuum adsorption platform.

[0031] Among them, the PDLC film can be prepared using existing technologies, such as Figure 1 As shown, the PDLC film includes a liquid crystal layer 3, two conductive (ITO) layers 2 and two substrate (PET) layers 1. The two ITO layers 2 are respectively placed on the upper and lower surfaces of the liquid crystal layer 3, and the two PET layers 1 are respectively placed on the surfaces of the two ITO layers 2. In this embodiment, it is necessary to laser etch and mark on the upper ITO layer 2.

[0032] In this embodiment, a vacuum adsorption platform is used to adsorb and fix the PDLC film so that the PDLC film is flat and does not warp. Preferably, the surface level error of the PDLC film on the vacuum adsorption platform is less than 20 μm, ensuring the accuracy of subsequent laser etching and the consistency of the line width.

[0033] Preferably, the temperature of the vacuum adsorption platform is designed to be controllable and controlled within the phase transition temperature range of the liquid crystal material of the liquid crystal layer to prevent liquid crystal abnormalities caused by ambient temperature fluctuations. Specifically, in this embodiment, the temperature of the vacuum adsorption platform is controlled at 20±5°C.

[0034] S2. Use a femtosecond laser to emit laser and adjust the laser light path so that the laser is focused on the ITO layer close to the PET layer through the PET layer on the surface of the PDLC film, and laser etching and marking are performed on the ITO layer according to a preset path.

[0035] Specifically, the laser wavelength emitted by the femtosecond laser is 300-400nm. This specific laser wavelength is selected based on the absorption characteristics of the liquid crystal material of the liquid crystal layer, which is conducive to efficient energy coupling and avoids unnecessary photothermal reaction. At the same time, the laser pulse width is designed to be less than 1000fs, the laser frequency is 100-2000KHz, the laser energy is 0.8-1.2μJ, and the scanning speed is 50-200mm / s. Since the femtosecond laser pulse is extremely short, ultra-high precision processing can be achieved, and extremely fine and complex process structures can be manufactured. In addition, the femtosecond laser pulse has a short duration and a small thermal effect, which effectively avoids the influence of heat diffusion on surrounding materials, reduces thermal damage and thermal deformation, and ensures the quality and performance of the processing area.

[0036] Furthermore, the spot diameter after laser focusing is controlled to be in the micrometer level, preferably 5 to 20 μm, to ensure that the laser energy density is highly concentrated on the scribing position.

[0037] In some embodiments, the height between the femtosecond laser and the vacuum adsorption platform can be adjusted so that the laser can pass through the PET layer on the surface of the PDLC film and focus on the upper ITO layer, so that the laser energy is completely absorbed by the ITO layer to form a uniformly cleaned line, while the PET layer is not damaged by the laser.

[0038] In this embodiment, the effect of different focusing positions of the laser inside the ITO layer on the scribing effect of the PDLC film was investigated experimentally, wherein the femtosecond laser processing parameters were set as follows: laser wavelength 355nm, laser frequency 800KHz, laser energy 1μJ, scanning speed 100mm / s, laser spot size 10μm after focusing; the results are shown in Table 1.

[0039] Table 1:

[0040]

[0041] From the results in Table 1, it can be seen that the laser focused spot is located inside the ITO layer and at a distance of 0.1 to 0.15 mm from the upper / lower surface of the ITO layer, which can make the PDLC film scribing width less than 20 μm, and the scribing effect is clear and the line width is uniform.

[0042] This embodiment also investigates the effect of different laser energies on the scribing effect of the PDLC film, wherein the femtosecond laser processing parameters are set as follows: laser wavelength 355nm, laser frequency 800KHz, scanning speed 100mm / s, laser spot size 10μm after focusing, and the laser focusing position is located at a distance of 0.1mm from the lower surface of the ITO layer; the results are shown in Table 2.

[0043] Table 2:

[0044]

[0045] From the results in Table 2, it can be seen that when the laser energy parameter is set at 0.8-1.2 μJ, the width of the PDLC film line can be less than 20 μm, and the line effect is clear, the line width is uniform, and the surface PET substrate is not damaged.

[0046] In addition, this embodiment also investigates the effect of different scanning speeds on the scribing effect of the PDLC film, wherein the femtosecond laser processing parameters are set as follows: laser wavelength 355nm, laser frequency 800KHz, laser energy 1μJ, laser focusing spot 10μm, laser focusing at a distance of 0.1mm from the lower surface of the ITO layer; the results are shown in Table 3.

[0047] Table 3:

[0048]

[0049]

[0050] From the results in Table 3, it can be seen that when the scanning speed is 50-200 mm / s, that is, when the spot overlap rate is 97.5-99.4%, the PDLC film line width can be less than 20 μm, and the line effect is clear, the line width is uniform, and the surface PET substrate is not damaged.

[0051] Therefore, by using the laser processing method of this embodiment in which the high-energy, high-precision ultrashort pulse femtosecond laser is focused on the ITO layer inside the PDLC film for etching and marking, the width of the internal markings of the PDLC film can reach less than 20μm, thereby improving its marking accuracy, providing the possibility for the partition control and high-precision optical performance of the PDLC film, and achieving higher image resolution and clarity. More and more complex patterns or circuits can be engraved within the same area, thereby improving material utilization.

[0052] Embodiment 2:

[0053] like Figure 2 As shown, this embodiment provides a laser processing device for a fine-line width PDLC film, which is used for the laser processing of the above-mentioned fine-line width PDLC film, and specifically includes a femtosecond laser 4, an optical path adjustment component, and a vacuum adsorption platform 12 for adsorbing and fixing the PDLC film. The laser beam emitted by the femtosecond laser 4 passes through the optical path adjustment component and is focused on the PDLC film on the vacuum adsorption platform 12.

[0054] Specifically, the optical path adjustment component includes a 45° reflector 1 5, an adjustable beam expansion and collimation unit 6, a 45° reflector 2 7, an aperture 8, a 45° reflector 3 9, a galvanometer scanning unit 10 and a focusing lens 11, which are sequentially arranged along the laser optical path. The laser beam emitted by the femtosecond laser 4 passes through the high-precision beam expansion and collimation unit, and is matched with a high-speed galvanometer scanning unit and a precision focusing lens to ensure the collimation and roundness of the laser, so that the beam quality achieves the best effect.

[0055] Preferably, the laser processing device also includes an energy monitoring feedback module (not shown in the figure) for real-time monitoring of laser energy, which automatically adjusts the laser output power according to a preset laser energy threshold to cope with batch differences of PDLC films and ensure processing consistency.

[0056] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A laser processing method for a thin line width PDLC film, characterized in that: The steps include: S1. Place the PDLC film flat on a vacuum adsorption platform; S2. Use a femtosecond laser to emit laser and adjust the laser light path so that the laser is focused on the ITO layer close to the PET layer through the PET layer on the surface of the PDLC film, and laser etching and marking are performed on the ITO layer according to a preset path.

2. The laser processing method of the thin line width PDLC film according to claim 1, characterized in that: The laser wavelength emitted by the femtosecond laser is 300-400nm, the laser pulse width is less than 1000fs, the laser frequency is 100-2000KHz, the laser energy is 0.8-1.2μJ, and the scanning speed is 50-200mm / s.

3. The laser processing method of the thin line width PDLC film according to claim 1, characterized in that: The laser focused spot is located inside the ITO layer and at a distance of 0.1 to 0.15 mm from the upper / lower surface of the ITO layer.

4. The laser processing method of a thin line width PDLC film according to claim 1, characterized in that: The laser focusing spot diameter is 5-20 μm.

5. The laser processing method of a thin line width PDLC film according to claim 1, characterized in that: The line width of the laser-etched lines on the ITO layer inside the PDLC film is less than 20 μm.

6. The laser processing method of a thin line width PDLC film according to claim 1, characterized in that: The temperature of the vacuum adsorption platform is controlled within the phase transition temperature range of the liquid crystal material of the liquid crystal layer inside the PDLC film.

7. The laser processing method of a thin line width PDLC film according to claim 1, characterized in that: The surface level error of the PDLC film on the vacuum adsorption platform is less than 20 μm.

8. A fine line width PDLC film, characterized in that: A laser processing method system for a thin line width PDLC film according to any one of claims 1 to 7 is adopted.

9. A laser processing device for a fine line width PDLC film, characterized in that: The invention comprises a femtosecond laser, an optical path adjustment component and a vacuum adsorption platform for adsorbing and fixing a PDLC film. The laser beam emitted by the femtosecond laser passes through the optical path adjustment component and is focused on the PDLC film on the vacuum adsorption platform.

10. The laser processing device for a thin line width PDLC film according to claim 9, characterized in that: The optical path adjustment component comprises a 45° reflector 1, an adjustable beam expansion collimation unit, a 45° reflector 2, an aperture, a 45° reflector 3, a galvanometer scanning unit and a focusing lens which are sequentially arranged along the laser optical path.

Images