Sample preparation method for cross-sectional microstructure morphology analysis of optical films

Abstract

This invention provides a sample preparation method for analyzing the cross-sectional microstructure morphology of optical films, relating to the field of optical film technology. The method comprises: first, covering the microstructure surface of the optical film sample to be tested with a transparent PET protective film; then, using a sharp blade to cut the protected optical film, quickly obtaining a sample with a clear and complete cross-sectional microstructure morphology. Compared with traditional metallographic sample preparation methods, this application, by utilizing a transparent PET protective film to prepare the microstructure surface of the optical film sample to be tested, effectively shortens the sample preparation time, improves operational and analytical efficiency, and alleviates the problems of cumbersome and time-consuming sample preparation processes in existing metallographic analysis, featuring fast sample preparation efficiency and high cross-sectional quality.

Description

Technical Field

[0001] This invention relates to the field of optical film technology, and in particular to a sample preparation method for analyzing the cross-sectional microstructure morphology of optical films. Background Technology

[0002] The optical films in the backlight modules of common liquid crystal display (LCD) modules generally include diffusion films, brightness enhancement films, and composite films made up of these two types of films. The brightness enhancement film typically consists of a first substrate layer, a second scratch-resistant coating layer deposited on one side, and a third prism layer deposited on the other side. By utilizing the light-converging effect of the microstructures in the prism layer, the brightness of the backlight module at the forward viewing angle is effectively increased, thereby improving the overall energy efficiency of the LCD module. In particular, the period, apex angle, and other structural parameters of the prism layer microstructure are key factors affecting the light-converging effect.

[0003] Therefore, microstructure parameters are an important optical indicator in the manufacturing process of brightness enhancement films. At the same time, considering that brightness enhancement films are generally manufactured using a roll-to-roll continuous production process, ensuring the timeliness of testing and minimizing material waste are also key considerations.

[0004] Metallographic analysis is a common method in materials science for analyzing the microstructure, elements and composition of materials. It is also applicable to the morphological analysis of optical film microstructures. However, the samples to be tested and analyzed first need to be prepared by metallographic sampling, and then gold sputtered and placed in an electron microscope for observation, analysis and measurement.

[0005] Existing metallographic sample preparation methods typically include the following four steps:

[0006] First, cut larger samples (such as optical films with plastic films as substrates (polymethyl methacrylate PMMA, cellulose triacetate TAC, super phase retardation film SRF, and polyethylene terephthalate PET, etc.) to obtain samples of appropriate size.

[0007] Second, place the sample obtained from step one into a commercial mounting machine that has been filled with resin;

[0008] Third, after the resin has fully cured, remove the resin containing the sample from the mold;

[0009] Fourth, the sample obtained in step three is ground and polished using a grinding and polishing machine or by hand to prepare the metallographic sample to be observed.

[0010] Typically, epoxy resin is used to mount samples during metallographic sample preparation. It takes 6-8 hours to fully cure at room temperature, and even with high-temperature curing, it still takes 2-4 hours.

[0011] Therefore, although metallographic sample preparation can yield high-quality metallographic samples, the preparation process is cumbersome, time-consuming, and has low analytical efficiency. It is not conducive to obtaining test data quickly and cannot meet the requirements of analytical characterization efficiency in industrial production.

[0012] In view of this, the present invention is hereby proposed. Summary of the Invention

[0013] The purpose of this invention is to provide a sample preparation method for the analysis of the microstructure morphology of optical film cross sections. Compared with traditional metallographic sample preparation methods, the sample preparation method effectively shortens the sample preparation time, improves the efficiency of operation and analysis, and alleviates the problems of cumbersome and time-consuming sample preparation processes in existing metallographic analysis. It has the characteristics of fast sample preparation efficiency and high cross section quality.

[0014] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0015] This invention provides a sample preparation method for analyzing the cross-sectional microstructure morphology of optical films, the sample preparation method comprising:

[0016] S1: Provide the optical film sample to be tested and the PET protective film;

[0017] S2: Remove the release layer of the PET protective film, and then attach the adhesive layer of the PET protective film to the microstructure morphology surface of the optical film sample to be tested to obtain the coated sample to be tested.

[0018] The PET protective film comprises a transparent protective film layer, an adhesive layer, and a release layer arranged sequentially.

[0019] The transparent protective film layer of the PET protective film has a transmittance of >89% and a haze of <2%, and the viscosity of the PET protective film is 3~25gf / 25mm;

[0020] S3: Microscopic observation confirms the extension direction of the microstructure on the coated sample, and optical film strips are cut along the extension direction of the microstructure.

[0021] S4: Secure the optical film template to the cutting pad, then fix two L-shaped supports above the template. Adjust the position of one of the L-shaped supports to 90° between the blade and the film. Use a 1kg weight to quickly drop it from top to bottom from about 5-10cm directly above the blade, with an acceleration of 2.5-5cm / s². 2 The cut optical film strips were obtained;

[0022] During the cutting process, a transparent protective film layer is placed under the optical film sample to be tested;

[0023] S5: Peel off the transparent protective film layer to obtain an optical film sample with cross-sectional microstructure.

[0024] Furthermore, the optical film sample to be tested includes any one of the following: a 3D grating film with a microstructure, a wide-viewing-angle film, a light-diffusing film, and a brightness-enhancing film.

[0025] Furthermore, the thickness of the transparent protective film layer of the PET protective film is 38~100μm.

[0026] Furthermore, the adhesive layer thickness of the PET protective film is 5~20μm.

[0027] Furthermore, the adhesive system of the PET protective film is one of acrylic, polyurethane, or silicone.

[0028] Preferably, the adhesive system of the PET protective film is a polyurethane system.

[0029] Furthermore, the peel force of the PET protective film after being bonded to the optical film sample under test at 180° is 3~25gf / 25mm.

[0030] Furthermore, the optical film strip has a size of 100mm*10mm.

[0031] The sample preparation method for optical film cross-sectional microstructure morphology analysis provided by this invention is applied in the analysis of optical film cross-sectional microstructure morphology.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention provides a sample preparation method for analyzing the cross-sectional microstructure morphology of optical films. The method involves first covering the microstructure surface of the optical film sample to be tested with a transparent PET protective film, and then using a sharp blade to cut the protected optical film, quickly obtaining a sample with a clear and complete cross-sectional microstructure morphology. Compared with traditional metallographic sample preparation methods, this method effectively shortens the sample preparation time, improves operational and analytical efficiency, and alleviates the problems of cumbersome and time-consuming sample preparation processes in existing metallographic analyses. It features fast sample preparation efficiency and high cross-sectional quality. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1This is a schematic diagram of the optical film sample to be tested, the transparent PET protective film, and the transparent glass required for the sample preparation method provided in Embodiment 1 of the present invention;

[0036] Figure 2 These are schematic diagrams of the side and top views of the optical film sample to be tested after it has been fixed, as provided in Embodiment 1 of the present invention.

[0037] Figure 3 This is a schematic diagram of the process of applying a PET protective film to an optical film according to Embodiment 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the sample provided in Embodiment 1 of the present invention, which is covered with a PET protective film and an optical film, and cut into strips.

[0039] Figure 5 This is a schematic diagram of the structure of the cut optical film strip provided in Embodiment 1 of the present invention;

[0040] Figure 6 This is a schematic diagram of the structure for fixing and testing optical film strips provided in Embodiment 1 of the present invention.

[0041] Icons: 01-Optical film; 01a-Microstructure; 01b-Brightening film substrate; 01c-Back coating; 02-PET protective film; Release film-02a; 02b-Adhesive layer; 02c-Protective film substrate; 03-Flat transparent glass; 04-Laminating platform; 05-Transparent tape; 06-Handheld bonding roller; 07-Mechanical roller; 08-Cut and coated strip; 09-L-shaped fixing bracket; 10-Blade; 11-Cut pad; 12-Weight; 13-Cut strip. Detailed Implementation

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] According to one aspect of the present invention, a sample preparation method for morphological analysis of the cross-sectional microstructure 01a of an optical film 01 is provided, the sample preparation method comprising:

[0044] S1: Provide the optical film 01 sample to be tested and the PET protective film 02;

[0045] S2: Remove the release layer of the PET protective film 02, and then attach the adhesive layer 02b side of the PET protective film 02 to the microstructure 01a morphology surface of the optical film 01 sample to be tested, to obtain the coated sample to be tested.

[0046] The PET protective film 02 includes a transparent protective film layer, an adhesive layer 02b, and a release layer arranged sequentially.

[0047] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%. The adhesion of the PET protective film 02 to the test sample is 3~25gf / 25mm.

[0048] S3: Microscopic observation confirms the extension direction of microstructure 01a on the coated sample to be tested, and optical film 01 strip is obtained by cutting along the extension direction of microstructure 01a.

[0049] S4: Attach the optical film 01 template to the cutting pad and fix it in place. Then, fix two L-shaped supports above the optical film 01 template. Adjust the position of one of the L-shaped supports to adjust the angle between the blade 10 and the film to 90°. Use a 1kg weight 12 to quickly drop it from top to bottom from about 5-10cm directly above the blade 10. The acceleration of the blade 10 upon impact should be 2.5-5cm / s². 2 The cut optical film 01 spline was obtained;

[0050] During the cutting process, a transparent protective film layer is placed under the optical film 01 sample to be tested;

[0051] S5: Peel off the transparent protective film layer to obtain the optical film 01 template with cross-sectional microstructure 01a.

[0052] This invention provides a sample preparation method for analyzing the morphology of the cross-sectional microstructure 01a of an optical film 01. The method involves first covering the microstructure 01a surface of the optical film 01 sample to be tested with a transparent PET protective film 02, and then using a sharp blade 10 to cut the protected optical film 01, quickly obtaining a sample with a clear and complete cross-sectional microstructure 01a morphology. Compared with traditional metallographic sample preparation methods, this method effectively shortens the sample preparation time, improves operational and analytical efficiency, and alleviates the problems of cumbersome and time-consuming sample preparation processes in existing metallographic analyses. It features fast sample preparation efficiency and high cross-sectional quality.

[0053] Meanwhile, the method and process used in this invention are simple, and samples with high-quality cross-sectional microstructure morphology can be prepared after simple training of the sample preparation personnel.

[0054] It should be noted that the PET protective film 02 used in this application is a PET protective film with high transmittance and low haze, so as to more clearly determine the extension direction of the microstructure 01a after it needs to be marked.

[0055] Preferably, the PET protective film 02 has a transmittance > 89% and a haze < 2%. When the transmittance of the PET protective film 02 is < 89% or the haze is > 2%, it is not conducive to confirming the extension direction of the microstructure 01a of the coated optical film 01.

[0056] In a preferred embodiment of the present invention, the optical film sample to be tested 01 includes any one of a 3D grating film, a wide-viewing-angle film, a light-diffusing film, and a brightness-enhancing film having a microstructure 01a.

[0057] In a preferred embodiment of the present invention, the thickness of the transparent protective film layer of the PET protective film 02 is 38~100μm, and the thickness of the adhesive layer 02b of the PET protective film 02 is 5~20μm.

[0058] As a preferred embodiment, the thickness of the above-mentioned transparent protective film layer and adhesive layer 02b can, on the one hand, fully fix the microstructure 01a, and on the other hand, avoid excessive adhesive layer 02b overflowing during the cutting process and causing contamination of the microstructure 01a.

[0059] In a preferred embodiment of the present invention, the adhesion of the PET protective film 02 is 3-25gf / 25mm.

[0060] In a preferred embodiment of the present invention, the adhesive system of the PET protective film 02 is one of acrylic, polyurethane or silicone systems;

[0061] In the preferred embodiment described above, the adhesive system of the PET protective film 02 is a polyurethane system.

[0062] As a preferred embodiment, the PET protective film 02 of the present invention is preferably a polyurethane system or a silicone system PET protective film 02. The polyurethane system PET protective film 02 has good air venting performance, which can effectively avoid the formation of fine air bubbles after coating, making it impossible to clearly identify the extension direction of the microstructure 01a under a microscope, and thus causing deviations in the sample preparation process.

[0063] More preferably, in order to facilitate the differentiation of the extension direction of the microstructure 01a after bonding, a silicone system with a lower refractive index is preferred as the protective film adhesive system used in this invention, so as to improve the identification of the PET protective film 02 adhesive layer 02b and the microstructure 01a under a microscope.

[0064] In a preferred embodiment of the present invention, the peel force of the PET protective film 02 after being bonded to the optical film 01 sample at 180° is 3~25gf / 25mm. This peel force selection effectively avoids the protective film peeling off during the alignment, cutting, and transfer of the sample, thus preventing the sample preparation success from being affected.

[0065] In a preferred embodiment of the present invention, the size of the optical film 01 sample is 100mm*10mm.

[0066] According to one aspect of the present invention, the sample preparation method for morphology analysis of cross-sectional microstructure 01a of optical film 01 can be widely applied to morphology analysis of cross-sectional microstructure 01a of optical film 01.

[0067] The technical solution of the present invention will be further described below with reference to the embodiments.

[0068] The following embodiments use commercially available brightness enhancement film materials as examples to verify the sample preparation method for analyzing the cross-sectional microstructure 01a of the optical film 01 in this application. Specifically, the optical film 01 sample to be tested in the following embodiments is a commercially available brightness enhancement film material, and the optical microstructure 01a it adopts is an isosceles right triangle with a period of 50 μm and a vertex angle of 90°.

[0069] Example 1

[0070] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0071] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0072] Figure 1 This is a schematic diagram of the optical film 01 sample to be tested, the transparent PET protective film 02, and the transparent glass required for the sample preparation method in this embodiment. Figure 1 (a) is a top view and a side view of the structure of the brightness enhancement film; the brightness enhancement film includes an optical film 01, a microstructure 01a, a brightness enhancement film substrate 01b, and a back coating 01c. Figure 1 (b) is a top view and a side view of the PET protective film 02; the PET protective film 02 includes a release film 02a, an adhesive layer 02b, and a protective film substrate 02c. Figure 1 (c) is a flat, transparent glass 03.

[0073] The transparent PET protective film 02 is a silicone-based PET protective film 02 (Penglin PLSAT-PAD04). The substrate (transparent protective film layer) of the silicone-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 5um.

[0074] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0075] 2. Place the transparent glass on a flat bonding platform 04, then place the microstructure 01a side of the optical film 01 sample upwards on top of the transparent glass, and secure the front end with transparent tape 05. Figure 2 As shown.

[0076] Figure 2 This is a schematic diagram showing the side and top views of the optical film 01 sample after it has been fixed.

[0077] Figure 2 (a) is a side view of the optical film 01 sample after it has been fixed. Figure 2 (b) is a top view of the optical film 01 sample after it has been fixed.

[0078] 3. Tear off the release film 02a of the transparent PET protective film 02, so that the adhesive layer 02b side of the PET protective film 02 faces the surface of the optical film 01 sample to be bonded. Use a handheld bonding roller 06 to cover a portion of the front end of the optical film 01 with the PET protective film 02, and then roll it to bond. Figure 3 As shown.

[0079] Figure 3 This is a schematic diagram of the process of applying a PET protective film 02 to the optical film 01 in this embodiment. Figure 3 (a) is a schematic diagram of the process of manually applying the PET protective film 02 to the optical film 01 in this embodiment. Figure 3 (b) is a schematic diagram of the process of applying PET protective film 02 to the optical film 01 using a laminating machine in this embodiment.

[0080] 4. Turn on the automatic laminating machine, set the laminating pressure to 0.1-0.3 MPa, and the laminating line speed to 100-300 mm / min. Use the mechanical roller 07 to laminate the optical film 01 sample to obtain the protective coating. Figure 3 As shown in (b).

[0081] 5. Place the optical film 01 sample obtained in step 4 under an optical microscope and observe it from the transparent PET protective film 02 side. Confirm and mark the extension direction of the microstructure 01a in the optical film 01, such as... Figure 4 As shown in (a).

[0082] Figure 4 This is a schematic diagram of the sample in this embodiment, after being covered with PET protective film 02 and optical film 01, and after being cut into strips. Figure 4 (a) is a schematic diagram of a sample covered with PET protective film 02 and optical film 01; Figure 4 (b) is a schematic diagram of the sample after it has been cut into strips.

[0083] 6. Cut along the extension direction to obtain an optical film 01 strip with a length and width of 100mm*10mm, wherein the length direction is along the extension direction of microstructure 01a, and the width direction is orthogonal to the extension direction of microstructure 01a, to obtain the cut and coated strip 08. Figure 4 As shown in (b).

[0084] 7. Smoothly attach the optical film 01 sample to a cutting pad (commercially available PVC soft rubber pad) using transparent tape 05. Then, fix two L-shaped fixing brackets 09 above the optical film 01 sample, leaving a gap in the middle, the gap being slightly wider than the thickness of the blade 10. Place the cutting pad 11 below. Figure 5 As shown in (a).

[0085] Figure 5 This is a schematic diagram of the structure of the cut optical film 01 strip provided in this embodiment. Wherein: Figure 5 (a) is a top view of the structure of the cut optical film 01 spline; Figure 5 (b) is a side view of the structure of the cut optical film 01 spline.

[0086] 8. Take a commercially available blade 10 (LEICA818, 80mm long * 14mm wide * 0.35mm thick), adjust the position of one of the L-shaped fixing brackets 09, and adjust the angle between the blade 10 and the diaphragm to 90°. Use a 1kg weight 12 to quickly drop it from top to bottom from about 5-10cm directly above the blade 10 to obtain the cut sample strip 13. Figure 5 As shown in (b);

[0087] 9. After peeling off the PET transparent protective film, fix the optical film 01 sample onto the fixture and analyze its cross-sectional morphology using a Keyence VK-X1000 microscope. Figure 6 As shown.

[0088] Figure 6 This is a schematic diagram of the structure used to fix and inspect the optical film 01 sample. Wherein: Figure 6 (a) is a top view of the structure used to fix and test the optical film 01 sample. In the top view, the microstructure 01a of the optical film 01 sample extends in a direction perpendicular to the paper. Figure 6 (b) is a side view of the structure used to fix and test the optical film 01 sample. In the side view, the microstructure 01a of the optical film 01 sample extends in a direction parallel to the paper.

[0089] Example 2

[0090] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0091] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0092] The transparent PET protective film 02 is a silicone-based PET protective film 02 (Penglin PLSAT-PAD04). The substrate (transparent protective film layer) of the silicone-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 10um.

[0093] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0094] 2-9, Same as Example 1.

[0095] The only difference between this embodiment and Example 1 is that the adhesive layer 02b of the silicone-based PET protective film 02 has a thickness of 10µm.

[0096] Example 3

[0097] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0098] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0099] The transparent PET protective film 02 is a silicone-based PET protective film 02 (Penglin PLSAT-PAD04). The substrate (transparent protective film layer) of the silicone-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 15um.

[0100] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0101] 2-9, Same as Example 1.

[0102] The only difference between this embodiment and Example 1 is that the thickness of the adhesive layer 02b of the silicone-based PET protective film 02 is 15µm.

[0103] Example 4

[0104] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0105] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0106] The transparent PET protective film 02 is a silicone-based PET protective film 02 (Penglin PLSAT-PAD04). The substrate (transparent protective film layer) of the silicone-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 20um.

[0107] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0108] 2-9, Same as Example 1.

[0109] Except for the fact that the thickness of the adhesive layer 02b of the silicone-based PET protective film 02 is 20um, which is different from that in Example 1, this embodiment is the same as in Example 1.

[0110] Example 5

[0111] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0112] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0113] The transparent PET protective film 02 is a polyurethane-based PET protective film 02 (Sticco 12154C). The substrate (transparent protective film layer) of the polyurethane-based PET protective film 02 is 50µm thick, and the adhesive layer 02b is 5µm thick.

[0114] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0115] 2-9, Same as Example 1.

[0116] This embodiment is the same as in Embodiment 1, except that the silicone-based PET protective film 02 in step 1 is replaced with a polyurethane-based PET protective film 02.

[0117] Example 6

[0118] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0119] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0120] The transparent PET protective film 02 is a polyurethane-based PET protective film 02 (Sticco 12154C). The substrate (transparent protective film layer) of the polyurethane-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 10um.

[0121] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0122] 2-9, Same as Example 1.

[0123] This embodiment is the same as embodiment 2 except that the silicone-based PET protective film 02 in step 1 is replaced with a polyurethane-based PET protective film 02.

[0124] Example 7

[0125] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0126] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0127] The transparent PET protective film 02 is a polyurethane-based PET protective film 02 (Sticco 12154C). The substrate (transparent protective film layer) of the polyurethane-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 15um.

[0128] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0129] 2-9, Same as Example 1.

[0130] This embodiment is the same as embodiment 3, except that the silicone-based PET protective film 02 in step 1 is replaced with a polyurethane-based PET protective film 02.

[0131] Example 8

[0132] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0133] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0134] The transparent PET protective film 02 is a polyurethane-based PET protective film 02 (Sticco 12154C). The substrate (transparent protective film layer) of the polyurethane-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 20um.

[0135] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0136] 2-9, Same as Example 1.

[0137] This embodiment is the same as embodiment 4, except that the silicone-based PET protective film 02 in step 1 is replaced with a polyurethane-based PET protective film 02.

[0138] Example 9

[0139] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0140] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0141] The transparent PET protective film 02 is an acrylic-based PET protective film 02 (Fantek FC2514L). The substrate (transparent protective film layer) of the acrylic-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 5um.

[0142] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0143] 2-9, Same as Example 1.

[0144] This embodiment is the same as embodiment 1, except that the silicone-based PET protective film 02 in step 1 is replaced with an acrylic-based PET protective film 02.

[0145] Example 10

[0146] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0147] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0148] The transparent PET protective film 02 is an acrylic-based PET protective film 02 (Fantek FC2514L). The substrate (transparent protective film layer) of the acrylic-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 10um.

[0149] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0150] 2-9, Same as Example 1.

[0151] This embodiment is the same as embodiment 2 except that the silicone-based PET protective film 02 in step 1 is replaced with an acrylic-based PET protective film 02.

[0152] Example 11

[0153] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0154] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0155] The transparent PET protective film 02 is an acrylic-based PET protective film 02 (Fantek FC2514L). The substrate (transparent protective film layer) of the acrylic-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 15um.

[0156] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0157] 2-9, Same as Example 1.

[0158] This embodiment is the same as embodiment 3, except that the silicone-based PET protective film 02 in step 1 is replaced with an acrylic-based PET protective film 02.

[0159] Example 12

[0160] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0161] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0162] The transparent PET protective film 02 is an acrylic-based PET protective film 02 (Fantek FC2514L). The substrate (transparent protective film layer) of the acrylic-based PET protective film 02 is 50um, and the thickness of the adhesive layer 02b is 20um.

[0163] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0164] 2-9, Same as Example 1.

[0165] This embodiment is the same as embodiment 4, except that the silicone-based PET protective film 02 in step 1 is replaced with an acrylic-based PET protective film 02.

[0166] Comparative Example 1

[0167] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0168] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0169] The transparent PET protective film 02 is a silicone-based PET protective film 02 with extremely low adhesion (Sticco SDK2194X). The substrate (transparent protective film layer) of the PET protective film 02 has a thickness of 50µm, and the adhesive layer 02b has a thickness of 5µm.

[0170] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0171] 2-9, Same as Example 1.

[0172] This embodiment is the same as embodiment 4, except that the silicone-based PET protective film 02 in step 1 is replaced with a silicone-based PET protective film 02 with extremely low adhesion.

[0173] Comparative Example 2

[0174] A sample preparation method for morphological analysis of the microstructure 01a of the cross-section of an optical film 01, the sample preparation method comprising:

[0175] 1. Take one sample of the optical film 01 to be tested, measuring 200mm*300mm; one sample of the transparent PET protective film 02, measuring 180mm*270mm; and one piece of smooth and clean transparent glass, measuring 300mm*500mm. The structural diagram is shown below. Figure 1 As shown.

[0176] The transparent PET protective film 02 is a silicone-based PET protective film 02 with high adhesion (Sticco SDK8105G). The substrate (transparent protective film layer) of the PET protective film 02 has a thickness of 50um, and the adhesive layer 02b has a thickness of 5um.

[0177] The transparent protective film layer of the PET protective film 02 has a transmittance of >89% and a haze of <2%.

[0178] 2-9, Same as Example 1.

[0179] This embodiment is the same as embodiment 4, except that the silicone-based PET protective film 02 in step 1 is replaced with a silicone-based PET protective film 02 with higher adhesion.

[0180] Experimental Example 1

[0181] Following the experimental procedures of Examples 1-12 and Comparative Examples 1 and 2, the optical film 01 sample to be tested was sequentially coated and cut into 6 strips of the same size (numbered 1#, 2#, 3#, 4#, 5#, and 6#), wherein:

[0182] (1) The optical film 01 was prepared using the above-mentioned fixture to obtain the sample to be tested. The morphology was analyzed using a Keyence microscope. The data obtained from the three sample tests and the clarity of the microstructure were recorded.

[0183] (2) The peel force of the other three samples was tested according to the national standard GB2792-2014 at 180°. The relevant test data were recorded and summarized in Table 1 and Table 2.

[0184] Table 1:

[0185]

[0186] Table 2:

[0187]

[0188] As can be seen from the above, the silicone or polyurethane-based PET protective film 02 used in Examples 1-8 has good air permeability. After coating, the orientation of the underlying microstructure 01a can be easily distinguished, thereby improving the accuracy of cutting the extension direction of the microstructure 01a. Furthermore, a silicone-based film with a larger refractive index deviation from the resin forming the microstructure 01a is preferred, making the adhesive layer 02b and the underlying microstructure 01a easier to identify under a microscope.

[0189] Examples 9-12 use acrylic PET protective film 02, which easily introduces air during the bonding process, affecting the identification of the orientation of microstructure 01a under a microscope. This can easily cause the orientation deviation of microstructure 01a during cutting, resulting in the cut microstructure 01a cross-section being a non-target cross-section and causing sample preparation errors.

[0190] Comparative Examples 1 and 2 show that when the 180° peel force of the protective film is too low or too high, sample preparation problems are also easily caused. When the 180° peel force of the protective film is too low, the protective film is prone to peeling off or shifting during sample preparation, cutting, and transfer, which may result in partial damage to the microstructure 01a. On the other hand, when the 180° peel force is too high, the protective film is prone to partially remaining on the surface of the microstructure 01a, forming contamination and making it difficult to identify the parameters of the microstructure 01a.

[0191] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sample preparation method for analyzing the cross-sectional microstructure morphology of optical films, characterized in that, The sample preparation method includes: S1: Provide the optical film sample to be tested and the PET protective film; S2: Remove the release layer of the PET protective film, and then attach the adhesive layer of the PET protective film to the side of the optical film sample to be tested with the microstructure morphology to obtain the coated sample to be tested. The PET protective film comprises a transparent protective film layer, an adhesive layer, and a release layer arranged sequentially. The PET protective film has a transparent protective film layer with a transmittance of >89% and a haze of <2%, and the PET protective film has an adhesion of 3~25gf / 25mm to the test sample. S3: Microscopic observation confirms the extension direction of the microstructure on the coated sample, and optical film strips are cut along the extension direction of the microstructure. S4: Secure the optical film template to the cutting pad, then fix two L-shaped supports above the template. Adjust the position of one of the L-shaped supports to 90° between the blade and the film. Use a 1kg weight to quickly drop it from top to bottom from about 5-10cm directly above the blade, with an acceleration of 2.5-5cm / s². 2 The cut optical film strips were obtained; The blade is located between two L-shaped supports to allow for adjustment of the blade angle using the two supports. During the cutting process, a transparent protective film layer is placed under the optical film sample to be tested; S5: Peel off the transparent protective film layer to obtain an optical film sample with cross-sectional microstructure.

2. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The optical film sample to be tested includes any one of the following: 3D grating film with microstructure, wide-viewing-angle film, light-diffusing film, and brightness-enhancing film.

3. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The thickness of the transparent protective film layer of the PET protective film is 38~100μm.

4. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The adhesive layer thickness of the PET protective film is 5~20μm.

5. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The adhesive system of the PET protective film is one of acrylic, polyurethane, or silicone.

6. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 5, characterized in that, The adhesive system of the PET protective film is either polyurethane or silicone.

7. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 6, characterized in that, The adhesive system of the PET protective film is a polyurethane system.

8. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The peel force of the PET protective film after being bonded to the optical film sample under test at 180° is 3~25gf / 25mm.

9. The sample preparation method for analyzing the cross-sectional microstructure morphology of optical films according to claim 1, characterized in that, The optical film strip has a size of 100mm*10mm.

10. The sample preparation method for optical film cross-sectional microstructure morphology analysis according to any one of claims 1 to 9 is applied to the analysis of optical film cross-sectional microstructure morphology.

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