Preparation method of multilayer optical film with controllable layer sequence distribution

Abstract

The invention discloses a preparation method of a multilayer optical film with controllable layer sequence distribution, and relates to the technical field of multilayer optical film preparation, layer group units sequentially pass through at least one non-uniform laminating device to form a multilayer body, and the multilayer body is post-processed to form the multilayer optical film; each layer group unit comprises a high refractive index layer and a low refractive index layer which are sequentially stacked in a staggered mode. The non-uniform laminating device comprises a first channel with a first inlet and a first outlet and a second channel with a second inlet and a second outlet; the first outlet and the second outlet are distributed up and down, the width of a first micro-layer flowing out of the first outlet is the same as that of a second micro-layer flowing out of the second outlet, and the thickness of the first micro-layer is different from that of the second micro-layer; the layer group units are shunted at the first inlet and the second inlet and then flow out from the first outlet and the second outlet respectively, and the first micro-layer and the second micro-layer are converged together again through an upper and lower laminated structure. Precise regulation and control of the layer thickness sequence can be realized, and the performance of the optical film is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-layer optical film preparation, and particularly to a method for preparing a multi-layer optical film with controllable layer sequence distribution. Background Art

[0002] Electromagnetic waves refract and reflect at the interface between two phases with different refractive indices. Due to the presence of multiple parallel interfaces in a multi-layer structure, incident electromagnetic waves will reflect multiple times at the interfaces. When the product of the refractive index and thickness of a single layer (i.e., optical thickness) is equal to one-fourth of the wavelength, the multi-layer structure can modulate the optical path difference of the reflected wave, resulting in constructive interference of the reflected waves in the same phase, thereby achieving selective reflection of electromagnetic waves with specific wavelengths.

[0003] To achieve high-intensity reflection, a large refractive index difference between the two-phase materials is usually required. However, the refractive index difference in the polymer system is small. Therefore, it is often necessary to increase the number of film layers to improve the reflectivity. Traditional methods for preparing polymer optical films, such as spin coating, vapor deposition, self-assembly, etc., have problems of low preparation efficiency and high unit cost. Especially in large-scale applications, they face obvious technical and economic bottlenecks. In contrast, inorganic material coating can achieve high-intensity reflection in a wide wavelength band with fewer layers due to its large refractive index difference. However, in the field of multi-passband filtering, it is still difficult to precisely control the transmission and reflection properties of specific narrow wavelength bands, and the processing conditions are relatively demanding. Currently, there is no technical solution that can efficiently prepare a polymer multi-layer optical film with controllable layer sequence distribution.

[0004] Therefore, there is an urgent need for a method for preparing a multi-layer optical film that can be efficiently prepared and has a controllable layer thickness sequence distribution, so as to achieve precise control of the layer sequence, improve the performance of the optical film, reduce production costs, and improve production efficiency to meet the needs of fine control and large-scale applications. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a multi-layer optical film with controllable layer sequence distribution to solve the problems existing in the above-mentioned prior art, and to be able to achieve precise control of the layer thickness sequence and improve the performance of the optical film.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a method for preparing a multilayer optical film with controllable layer sequence distribution, wherein the prepared layer group unit is sequentially passed through at least one non-uniform layer stacker to form a multilayer body, and the multilayer body is post-processed to form a multilayer optical film; wherein the layer group unit comprises at least one high refractive index layer and at least one low refractive index layer, and the refractive index of the high refractive index layer is different from that of the low refractive index layer; and the high refractive index layer and the low refractive index layer in the layer group unit are sequentially stacked up and down in an alternating manner; the non-uniform layer stacker comprises a first channel and a second channel; the first channel has a first inlet and a first outlet, and the second channel has a second inlet and a second outlet; the first outlet and the second outlet are distributed up and down, the width of a first microlayer flowing out of the first outlet is the same as the width of a second microlayer flowing out of the second outlet, and the thickness of the first microlayer flowing out of the first outlet is different from the thickness of the second microlayer flowing out of the second outlet; after the layer group unit is split at the first inlet and the second inlet, it flows out from the corresponding first outlet and the second outlet respectively, and the first microlayer flowing out of the first outlet and the second microlayer flowing out of the second outlet are reunited in an up-down stacking structure.

[0008] Preferably, the first inlet and the second inlet are both located on a first plane, and the first inlet and the second inlet are distributed left and right on the first plane; the first outlet and the second outlet are both located on a second plane, and the first outlet and the second outlet are distributed up and down on the second plane; the width of the first inlet is W A , the width of the second entrance is W B , the height of the first inlet and the second inlet are both H; the width of the first outlet and the width of the second outlet are both W, and the height of the first outlet is H A , the height of the second outlet is H B ; Where W = W A +W B , H=H A +H B .

[0009] Preferably, the uppermost layer and the lowermost layer of the layer group unit at the first inlet and the uppermost layer and the lowermost layer of the first microlayer at the first outlet correspond one to one; and the uppermost layer and the lowermost layer of the layer group unit at the second inlet and the uppermost layer and the lowermost layer of the second microlayer at the second outlet correspond one to one.

[0010] Preferably, the layer group unit is formed by an initial two-layer body through at least one uniform layer stacker; the initial two-layer body is composed of the high refractive index layer and the low refractive index layer stacked together; the uniform layer stacker is used to uniformly divide and multiply the initial two-layer body into an upper and lower stacking structure.

[0011] Preferably, the post-processing includes a surface layer extrusion system; the number of the non-uniform layer stackers is multiple; the multilayer body flowing out of the last non-uniform layer stacker flows into the surface layer extrusion system, and the surface layer extrusion system can form surface body layers on the upper and lower surfaces of the multilayer body respectively.

[0012] Preferably, the post-processing includes the multilayer body sequentially passing through an expanding die, a cooling and traction system, a winding and trimming system, and biaxial stretching.

[0013] Preferably, the high refractive index layer is formed of a high refractive index optical resin, and a high refractive index inorganic nanofiller can be doped into the high refractive index optical resin or a stretching-induced molecular chain orientation crystallization treatment can be performed; the low refractive index layer is formed of a low refractive index optical resin, and a pore structure can be introduced by etching, stretching to form holes or inducing phase separation.

[0014] Preferably, the initial two-layer body is formed by a first extruder providing a first raw material and a second extruder providing a second raw material, which are respectively connected to an initial confluence and flow out from the initial confluence; the first raw material is used to form the high refractive index layer, and the second raw material is used to form the low refractive index layer.

[0015] Preferably, the number of the uniform layer stackers and the non-uniform layer stackers are both multiple; the uniform layer stackers are connected in series in sequence, and the non-uniform layer stackers are connected in series in sequence, and the output end of the last uniform layer stacker is connected to the input end of the first non-uniform layer stacker.

[0016] Preferably, functional particles are added into the surface layer.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The method for preparing a multilayer optical film with controllable layer sequence distribution provided by the present invention provides a basic unit for constructing a multilayer optical film with specific optical properties by sequentially staggering high refractive index layers and low refractive index layers in the layer group unit. The non-uniform layer stacker allows the microlayers to re-converge in a specific upper and lower stacking structure. The thickness difference of the outflow layer structure from the first outlet and the second outlet of the non-uniform layer stacker is utilized to further increase the flexibility of the layer sequence design. By controlling the diversion and convergence of the layer group unit in different channels, microlayers of different thicknesses can be accurately arranged according to design requirements to achieve complex layer sequence distribution, providing more possibilities for preparing multilayer optical films with special optical properties, thereby more accurately adjusting the interference, reflection, refraction and transmission of light in the film layer, and realizing precise control of parameters such as reflectivity, transmittance and absorptivity of the optical film to meet the requirements of different optical systems for specific optical properties. The structure and working principle of the non-uniform layer stacker are relatively stable, and the repeatability and consistency of the process can be guaranteed during the preparation of the multilayer optical film. This means that in large-scale production, product quality can be controlled more stably, the yield rate can be improved, and product performance differences caused by process fluctuations can be reduced; by precisely controlling the distribution of layer sequences, multilayer optical films can achieve some special optical functions, such as narrowband filtering, polarization separation, etc. The combination of microlayers with different thicknesses and refractive indices can form a specific optical microstructure, which can finely control the polarization state and wavelength of light, expanding the application of multilayer optical films in optical communications, optical sensors and other fields; through the micro-nano stacking co-extrusion technology composed of multiple non-uniform stackers, efficient and precise preparation of polymer multilayer films can be achieved, which can not only optimize optical performance, but also greatly reduce production costs and production efficiency, and has broad application prospects, especially in the fields of fine control and large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of the preparation process of the method for preparing a multilayer optical film with controllable layer sequence distribution provided by the present invention;

[0021] Figure 2 A schematic diagram of the structure of a non-uniform layer stacker in the method for preparing a multilayer optical film with controllable layer sequence distribution provided by the present invention;

[0022] Figure 3 A flow chart of preparing a multilayer optical film by the method for preparing a multilayer optical film with controllable layer sequence distribution provided by the present invention;

[0023] Figure 4 A preparation flow chart of the cooperation between a plurality of uniform layer stackers and a plurality of non-uniform layer stackers in the preparation method of a multilayer optical film with controllable layer sequence distribution provided by the present invention;

[0024] Figure 5 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 1;

[0025] Figure 6 is the reflectance spectrum of the multilayer optical film in specific case 1;

[0026] Figure 7 This is an electron microscope image of the cross section of the prepared sample of the multilayer optical film in specific case 1;

[0027] Figure 8 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 2;

[0028] Fig. 9 is the reflectance spectrum of the multilayer optical film in specific case 2;

[0029] Fig.10 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 3;

[0030] Fig.11 is the reflectance spectrum of the multilayer optical film in specific case 3;

[0031] Fig.12 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 4;

[0032] Fig.13 is the reflectance spectrum of the multilayer optical film in specific case 4;

[0033] Fig.14 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 5;

[0034] Fig.15 is the reflectance spectrum of the multilayer optical film in specific case 5;

[0035] Fig.16 is a layer thickness sequence distribution diagram of the multilayer optical film in specific case 6;

[0036] Fig.17 is the reflectance spectrum of S light of the multilayer optical film in specific case 6;

[0037] Fig.18 is the reflectance spectrum of P light of the multilayer optical film in specific case 6;

[0038] Fig.19 This is an electron microscope image of the cross-section of the prepared sample of the multilayer optical film in specific case 6.

[0039] In the figure:

[0040] 10-evenly layered stacker;

[0041] 20- non-uniform layer stacker;

[0042] 30-initial confluence;

[0043] 40-Surface concentrator. DETAILED DESCRIPTION

[0044] 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.

[0045] The purpose of the present invention is to provide a method for preparing a multilayer optical film with controllable layer sequence distribution, so as to solve the problems existing in the prior art, achieve precise control of the layer thickness sequence, and improve the performance of the optical film.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1

[0048] This embodiment provides a method for preparing a multilayer optical film with controllable layer sequence distribution, such as Figures 1 to 19 As shown, the prepared layer group units are sequentially passed through at least one non-uniform layer stacker 20 to form a multilayer body, and the multilayer body is post-processed to form a multilayer optical film;

[0049] The layer group unit includes at least one high refractive index layer and at least one low refractive index layer, and the high refractive index layer and the low refractive index layer have different refractive indices; and the high refractive index layer and the low refractive index layer in the layer group unit are stacked alternately up and down in sequence (i.e., high refractive index layer, low refractive index layer, high refractive index layer, etc. in sequence);

[0050] The heterogeneous stacker 20 includes a first channel and a second channel; the first channel has a first inlet and a first outlet, and the second channel has a second inlet and a second outlet; the first outlet and the second outlet are distributed up and down, the width of the first microlayer flowing out of the first outlet is the same as the width of the second microlayer flowing out of the second outlet, and the thickness of the first microlayer flowing out of the first outlet is different from the thickness of the second microlayer flowing out of the second outlet; the layer group unit is separated at the first inlet and the second inlet and flows out from the corresponding first outlet and second outlet respectively (that is, the layer group unit is separated and separated at the inlet of the heterogeneous stacker 20, a part flows out from the first outlet through the first channel, and the other part flows out from the second outlet through the second channel), and the first microlayer flowing out of the first outlet and the second microlayer flowing out of the second outlet are reunited in an up-down stacking structure.

[0051] By staggeredly stacking high-refractive-index layers and low-refractive-index layers in the layer group unit in sequence, a basic unit is provided for constructing a multilayer optical film with specific optical properties. The non-uniform layer stacker 20 allows the microlayers to recombine in a specific upper and lower stacking structure. The thickness difference of the outflow layer structure from the first outlet and the second outlet of the non-uniform layer stacker 20 is utilized to further increase the flexibility of the layer sequence design. By controlling the diversion and convergence of the layer group unit in different channels, microlayers of different thicknesses can be accurately arranged according to design requirements to achieve a complex layer sequence distribution, which provides more possibilities for preparing multilayer optical films with special optical properties, thereby more accurately adjusting the interference, reflection, refraction and transmission of light in the film layer, and realizing precise control of optical film reflectivity, transmittance, absorptivity and other parameters to meet the requirements of different optical systems for specific optical properties. The structure and working principle of the non-uniform layer stacker 20 are relatively stable, and the repeatability and consistency of the process can be guaranteed during the preparation of the multilayer optical film. This means that in large-scale production, product quality can be more stably controlled, the yield rate can be improved, and product performance differences caused by process fluctuations can be reduced; by precisely controlling the distribution of layer sequences, multilayer optical films can achieve some special optical functions, such as narrowband filtering, polarization separation, etc. The combination of microlayers with different thicknesses and refractive indices can form a specific optical microstructure, which can finely control the polarization state and wavelength of light, expanding the application of multilayer optical films in optical communications, optical sensors and other fields; through the micro-nano stacking co-extrusion technology composed of multiple non-uniform stackers 20, efficient and precise preparation of polymer multilayer films can be achieved, which can not only optimize optical performance, but also greatly reduce production costs and production efficiency, and has broad application prospects, especially in the fields of fine control and large-scale application.

[0052] Specifically, the thickness of each layer structure in the multilayer optical film (such as first microlayers and second microlayers of different thicknesses, high refractive index layers and low refractive index layers of different thicknesses, etc.) can be controlled according to the target band requirements by selecting different numbers of uniform layer stackers 10 in combination with different non-uniform layer stackers 20 set as required, so as to achieve the regulation requirements of different bands of electromagnetic waves (partial reflection in the visible light band, total reflection in the visible light band, transparent near-infrared total reflection in the visible light band, multi-band filtering in the visible infrared band, etc.), and at the same time have excellent mechanical properties and flexibility, and are suitable for display, heat insulation, functional buildings, filtering and other fields.

[0053] Specifically, by connecting a plurality of non-uniform layer stackers 20 with different segmentation ratios in series and by continuous non-uniform segmentation multiplication, the design and controllable distribution of the layer thickness sequence distribution is achieved.

[0054] Among them, the relevant description of the layer group unit:

[0055] In the optional scheme of this embodiment, it is more preferred that Figure 3 and Figure 4 As shown, the layer group unit consists of two initial layers (i.e. Figure 1 The initial two layers shown in the figure are formed by passing through at least one uniform layer stacker 10 (the uniform layer stacker 10 can be a special non-uniform layer stacker 20, that is, the corresponding R is 1, or it can be an existing stacker used to form two identical output objects for uniform division and multiplication); the initial two-layer body is composed of a high refractive index layer and a low refractive index layer stacked together (upper and lower stacking); the uniform layer stacker 10 is used to evenly divide and multiply the initial two-layer body into an upper and lower stacked structure.

[0056] In the optional scheme of this embodiment, it is more preferred that the high refractive index layer is formed by a high refractive index optical resin (such as polyethylene terephthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyamide, polyacrylonitrile and copolymers of the above materials), and the refractive index control strategy can be used to improve the refractive index of the film material by using the weighted addition principle, and the doping control strategy of doping high refractive index inorganic nanofillers (titanium dioxide, zirconium oxide, aluminum oxide, silicon nitride, etc.) is used to improve it; the low refractive index layer is formed by a low refractive index optical resin (such as polymethyl methacrylate, polyvinylidene fluoride, 4-methylpentene polymer, cycloolefin copolymer, polyethylene, polypropylene, polyvinyl alcohol and copolymers of the above materials), and the method of reducing the refractive index of the film material can be reduced by introducing a pore structure between the layers through etching, stretching to form holes or inducing phase separation, and then introducing low refractive index media such as air and solution. At the same time, the refractive index of the film layer can be anisotropically regulated by the bulk control strategy of the charge density of the stretching-induced molecular chain orientation crystallization control system.

[0057] In the optional scheme of this embodiment, it is more preferred that Figure 1 , Figure 3 and Figure 4 As shown, the initial two-layer body is formed by a first extruder providing a first raw material (corresponding to extruder 1 in the figure) and a second extruder providing a second raw material (corresponding to extruder 2 in the figure), which are respectively connected to an initial confluence 30 and flow out from the initial confluence 30; the first raw material is used to form a high refractive index layer, and the second raw material is used to form a low refractive index layer.

[0058] Specifically, the extruder is used in conjunction with a melt pump, which is a prior art and will not be described in detail here; by adjusting the speed ratio of the melt pump, the film thickness ratio of the high refractive index layer and the low refractive index layer can be accurately controlled (that is, the thickness of the high refractive index layer and the low refractive index layer can be the same or different), thereby optimizing and adjusting the film system design and the high-order reflection band.

[0059] Among them, the relevant description about the non-uniform layer stacker 20 is as follows:

[0060] In the optional scheme of this embodiment, it is more preferred that Figure 2 As shown, the first inlet and the second inlet are both located on the first plane, and the first inlet and the second inlet are distributed left and right on the first plane (the first plane and the second plane are the planes where the cross section of the corresponding flow channel is located); the first outlet and the second outlet are both located on the second plane, and the first outlet and the second outlet are distributed up and down on the second plane; the width of the first inlet is W A , the width of the second entrance is W B , the height of the first entrance and the second entrance are both H; the width of the first outlet and the width of the second outlet are both W, and the height of the first outlet is H A , the height of the second outlet is H B ; Where W = W A +W B , H=H A +H B The spatial volume of the first channel is V A , the spatial volume of the second channel is V B , V A / V B =R. (V A Associated with the inlet and outlet dimensions of the corresponding first channel, V B It is associated with the inlet and outlet dimensions of the corresponding second channel, that is, R is associated with the inlet and outlet dimensions of the first channel and the second channel. The focus is on the explanation of the principle of its formation, and each data setting can be set accordingly according to the required results)

[0061] In the optional scheme of this embodiment, it is more preferred that Figure 2As shown, the uppermost layer and the lowermost layer of the layer group unit at the first inlet correspond to the uppermost layer and the lowermost layer of the first microlayer at the first outlet; and the uppermost layer and the lowermost layer of the layer group unit at the second inlet correspond to the uppermost layer and the lowermost layer of the second microlayer at the second outlet (the layer group unit at the first inlet and the first microlayer at the first outlet are taken as examples: that is, the layer arrangement of each layer in the first microlayer is consistent with the layer arrangement of each layer in the second microlayer, and the uppermost layer of the layer group unit at the first inlet and the uppermost layer of the first microlayer at the first outlet are the same layer, and the lowermost layer thereof and the lowermost layer of the first microlayer are the same layer, wherein the same layer can be a high refractive index layer or a low refractive index layer).

[0062] Among them, the relevant instructions for post-processing:

[0063] In the optional scheme of this embodiment, it is more preferred that Figure 3 As shown, the post-processing includes a surface layer extrusion system; the number of the non-uniform layer stacker 20 is multiple; the multilayer body flowing out of the last non-uniform layer stacker 20 flows into the surface layer extrusion system, and the surface layer extrusion system can form surface body layers on the upper and lower sides of the multilayer body respectively. It is used to improve the surface quality and protect the structural stability of the multilayer body. By adding the surface layer extrusion system, the low viscosity melt is distributed between the multilayer melt and the wall surface according to the set ratio, thereby realizing the protection of the multilayer body during the extrusion process.

[0064] Specifically, the surface extrusion system includes an extruder C and a surface concentrator 40, both of which are prior arts, and their connection and related structures will not be described in detail here.

[0065] In the optional scheme of this embodiment, it is more preferred to add functional particles in the surface layer to carry out special functional designs such as patterning, encryption, UV resistance, anti-reflection, electromagnetic shielding, etc.

[0066] In the optional scheme of this embodiment, it is more preferred that Figure 3 As shown, the post-processing includes the multilayer body passing through the expansion die, cooling and traction system, winding and trimming system and biaxial stretching in sequence. Each process included in the post-processing is prior art and will not be described in detail here.

[0067] Among them, regarding other related instructions:

[0068] In the optional scheme of this embodiment, it is more preferred that Figure 4 As shown, there are multiple uniform layer stackers 10 and multiple non-uniform layer stackers 20; each uniform layer stacker 10 is connected in series in sequence, and each non-uniform layer stacker 20 is connected in series in sequence, and the output end of the last uniform layer stacker 10 is connected to the input end of the first non-uniform layer stacker 20.

[0069] Specifically, the film thickness sequence of the multilayer optical film prepared by the method for preparing a multilayer optical film with controllable layer sequence distribution provided by this embodiment is controllable, the number of layers can vary between 8 and 2048 layers, preferably between 128 and 1536 layers; the single layer thickness range is 15 to 10000 nanometers, preferably between 30 and 5000 nanometers, and particularly preferably between 50 and 3000 nanometers; the layer thickness gradient ratio range is 1 to 10, preferably between 1.5 and 8, and particularly preferably between 2 and 6. The distribution mode includes but is not limited to continuous linear, continuous nonlinear, discontinuous linear and discontinuous nonlinear distribution.

[0070] Core principle description: The core lies in precisely controlling the film thickness ratio and thickness sequence distribution by connecting the non-uniformly layered stackers 20 in series, thereby achieving the broadening of the reflection bandwidth, the improvement of the reflection brightness and the fine control of different bands.

[0071] Specifically, by connecting in series 20 non-uniform stackers with different separation ratios, the distribution of the layer thickness sequence can be controlled. Figure 1 As shown in FIG. 1 , when an initial layer stack (i.e., a layer group unit) with m layers (m≥2) flows through n non-uniform layer stackers 20 with different split ratios connected in series, a layer stack with m×2 n , and has 2 n When n non-uniform layer stackers 20 are connected in series according to their division ratio from small to large, 2 n The gradient of the layer stack thickness varies monotonically.

[0072] Specific case 1: A sequence distribution controllable multilayer optical film for polymer reflectors

[0073] Material selection: polyethylene terephthalate (PET) is selected for the high refractive index layer, and polymethyl methacrylate (PMMA) is selected for the low refractive index layer;

[0074] Preparation process:

[0075] The high and low refractive index layer materials are dried in a crystallization drying tower for more than 10 hours.

[0076] The dried materials are added to the feeding systems of the two extruders respectively. Figure 4The preparation is carried out according to the flow chart shown in the figure. The two extruders A and B (i.e., extruder 1 and extruder 2, the same position will not be explained again below) feed the material through the initial confluence device 30 to form an initial 2-layer structure, and then flow through 5 series-connected 1:1 (which is the ratio corresponding to R, the explanation of the same position below is the same, and R will not be introduced for explanation) uniform layer stackers 10 to form an initial 64-layer uniform layer stack. The 64-layer melt stack flows through the first non-uniform layer stacker 20 (0.97 / 1), the second non-uniform layer stacker 20 (0.92 / 1), and the third non-uniform layer stacker 20 (0.85 / 1) with three increasing segmentation ratios, forming 8 layer thickness distributions, each with 64 layers of layer thickness distribution, a total of 512 layers of gradient micro-nano layered structures, and after biaxial stretching, etc., a gradient multilayer total reflection silver film is prepared. The layer structure distribution of the multilayer optical film prepared in this embodiment is as follows: Figure 5 The corresponding spectrum is shown as Figure 6 The cross-sectional electron micrograph of the prepared sample is shown in Figure 7 As shown. By constructing a 1.6 layer thickness gradient ratio, the reflection band is broadened, the entire visible light band is reflected, and the preparation of a full polymer reflector is realized.

[0077] Specific case 2: A sequence distribution controllable multilayer optical film for structural color display

[0078] Material selection: polyethylene terephthalate (PET) is selected for the high refractive index layer, and polymethyl methacrylate (PMMA) is selected for the low refractive index layer;

[0079] Preparation process:

[0080] The high and low refractive index layer materials are dried in a crystallization drying tower for more than 10 hours.

[0081] The dried materials are added to the feeding systems of two extruders respectively. The A and B extruders extrude and feed the materials. The melt flows through the initial confluence device 30 to form an initial 4-layer structure (which is the prior art and will not be described in detail here). Four uniform layer stackers 10 are connected in series to form 64 layers of uniform layered stacked melt. The multi-layer melt flows through two series-connected non-uniform layer stackers 20 to form 256 layers of melt with 4 layer thickness distributions. It is calendered by a mirror roller to become an initial multi-layer sheet, and then subjected to biaxial stretching to complete the preparation of the multi-layer optical film.

[0082] The layer structure distribution of the multilayer optical film prepared in this embodiment is as follows Figure 8 The corresponding spectrum is shown as Fig. 9 As shown. By constructing a 1.25 layer thickness gradient ratio, the reflection band is broadened, the high wavelength band of visible light is reflected, and the preparation of a rainbow film with warm tones and high brightness is achieved.

[0083] Specific case 3: A multilayer optical film with controllable sequence distribution that combines warm color rendering and heat insulation

[0084] Material selection: Polyethylene terephthalate (PET) is selected for the high refractive index layer, and polymethyl methacrylate (PMMA) is selected for the low refractive index layer;

[0085] Preparation process:

[0086] Place the high and low refractive index layer materials in a crystallization drying tower and dry for more than 10 hours.

[0087] Add the dried materials to the feeding systems of two extruders respectively. Extruders A and B extrude and supply materials. Control the flow ratio by adjusting the rotational speed of the melt pump to regulate the optical thickness of the high and low refractive index layers to be equal. The melt flows through the initial confluence device 30 to form an initial 4-layer structure, and 4 series-connected uniform laminators 10 are used to form a 64-layer uniformly stacked melt. The multi-layer melt flows through 3 series-connected non-uniform laminators 20 to form a 512-layer melt with 8 layer thickness distributions, and it is rolled into an initial multi-layer sheet through a mirror roller, and then the preparation of the multi-layer optical film is completed through biaxial stretching, etc.

[0088] The layer structure distribution of the multi-layer optical film prepared in this example is as Fig.10 shown, and the corresponding spectrum is as Fig.11 shown. By constructing a 1.6 layer thickness gradient ratio, the reflection band is broadened, and the high-wavelength band of visible light and part of the near-infrared band are reflected, realizing the preparation of an optical film with both structural color display and heat insulation functions.

[0089] Specific case 4: A multi-layer optical film with controllable sequence distribution for transparent heat insulation

[0090] Material selection: Polyethylene terephthalate (PET) is selected for the high refractive index layer, and polyvinylidene fluoride (PVDF) is selected for the low refractive index layer;

[0091] Preparation process:

[0092] Place the high and low refractive index layer materials in a crystallization drying tower and dry for more than 10 hours.

[0093] Add the dried materials to the feeding systems of two extruders respectively. Extruders A and B extrude and supply materials. The melt flows through the initial confluence device 30 to form an initial 4-layer structure, and 4 series-connected uniform laminators 10 are used to form a 64-layer uniformly stacked melt. The multi-layer melt flows through 3 series-connected non-uniform laminators 20 to form a 512-layer melt with 8 layer thickness distributions, and it is rolled into an initial multi-layer sheet through a mirror roller, and then the preparation of the multi-layer optical film is completed through biaxial stretching, etc.

[0094] The layer structure distribution of the multi-layer optical film prepared in this example is as Fig.12 shown, and the corresponding spectrum is as Fig.13As shown. By constructing a 1.6 layer thickness gradient ratio, the reflection band is broadened, maintaining high transmittance in the visible light band while having high reflection in the near-infrared band, so as to achieve transparent heat insulation function.

[0095] Specific case 5: A multilayer optical film with controllable sequence distribution is used for visible light multi-band filtering material selection: polycarbonate (PC) is selected for the high refractive index layer, and polyvinylidene fluoride (PVDF) is selected for the low refractive index layer;

[0096] Preparation process:

[0097] The high and low refractive index layer materials are dried in a crystallization drying tower for more than 10 hours.

[0098] The dried materials are added to the feeding systems of two extruders respectively. Extruders A and B extrude the materials, and the melt flows through the initial confluence device 30 to form an initial 4-layer structure. The multi-layer melt flows through 4 uniform layer stackers 10 connected in series to form 64 layers of uniform layer stacked melt. The multi-layer melt flows through 2 non-uniform layer stackers 20 connected in series to form 256 layers of melt with 4 layer thickness distributions. It is calendered by mirror rollers to become an initial multi-layer sheet, and then subjected to biaxial stretching to complete the preparation of the multi-layer optical film.

[0099] The layer structure distribution of the multilayer optical film prepared in this embodiment is as follows Fig.14 The corresponding spectrum is shown as Fig.15 As shown. By constructing a discontinuous multi-layer thickness gradient ratio, the construction of multiple reflection bands in the visible light band is achieved, which is used for multi-passband filtering in the visible light band.

[0100] Specific case 6: A sequence distribution controllable multilayer optical film for polarization color display

[0101] Material selection: The high refractive index layer is made of polyethylene terephthalate (PET), and the low refractive index layer is made of polyethylene terephthalate and 1,4-cyclohexanedimethanol copolymer (PETG);

[0102] Preparation process:

[0103] The high and low refractive index layer materials are dried in a crystallization drying tower for more than 10 hours.

[0104] The dried materials are added to the feeding systems of two extruders respectively. Extruders A and B extrude the materials, and the melt flows through the initial confluence device 30 to form an initial 4-layer structure. Four uniform layer stackers 10 are connected in series to form 64 layers of uniform layer stacked melt. The multi-layer melt flows through two series-connected non-uniform layer stackers 20 to form 256 layers of melt with 4 layer thickness distributions. It is calendered by mirror rollers to become an initial multi-layer sheet, and then biaxially stretched to complete the preparation of the multi-layer optical film.

[0105] The layer structure distribution of the multilayer optical film prepared in this embodiment is as follows Fig.16The corresponding spectrum is shown as Fig.17 and Fig.18 The cross-sectional electron micrograph of the prepared sample is shown in Fig.19 By constructing a 1.25 layer thickness gradient ratio, the reflection band is broadened, and by designing different degrees of matching of the refractive index in the orthogonal direction, a high degree of selectivity for orthogonal polarized light is achieved, which is applied to polarization encryption and anti-counterfeiting.

[0106] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a multilayer optical film with controllable layer sequence distribution, characterized in that: Passing the prepared layer group units through at least one non-uniform layer stacker in sequence to form a multilayer body, and the multilayer body is post-processed to form a multilayer optical film; The layer group unit comprises at least one high refractive index layer and at least one low refractive index layer, and the high refractive index layer and the low refractive index layer have different refractive indexes; and the high refractive index layer and the low refractive index layer in the layer group unit are stacked alternately up and down in sequence; The non-uniform stacker includes a first channel and a second channel; the first channel has a first inlet and a first outlet, and the second channel has a second inlet and a second outlet; the first outlet and the second outlet are distributed up and down, the width of the first microlayer flowing out of the first outlet is the same as the width of the second microlayer flowing out of the second outlet, and the thickness of the first microlayer flowing out of the first outlet is different from the thickness of the second microlayer flowing out of the second outlet; the layer group unit flows out from the corresponding first outlet and the second outlet respectively after being split at the first inlet and the second inlet, and the first microlayer flowing out of the first outlet and the second microlayer flowing out of the second outlet are reunited in an up-and-down stacking structure.

2. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The first inlet and the second inlet are both located on a first plane, and the first inlet and the second inlet are distributed left and right on the first plane; The first outlet and the second outlet are both located on a second plane, and the first outlet and the second outlet are distributed up and down on the second plane; The width of the first inlet is W A , the width of the second entrance is W B , the heights of the first entrance and the second entrance are both H; The width of the first outlet and the width of the second outlet are both W, and the height of the first outlet is H. A , the height of the second outlet is H B ; Wherein, W = W A + W B , H = H A + H B .

3. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The uppermost layer and the lowermost layer of the layer group unit at the first inlet correspond to the uppermost layer and the lowermost layer of the first microlayer at the first outlet; And the uppermost layer and the lowermost layer of the layer group unit at the second inlet and the uppermost layer and the lowermost layer of the second microlayer at the second outlet correspond one to one.

4. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The layer group unit is formed by initially two layers through at least one homogeneous layer stacker; The initial two-layer body is composed of the high refractive index layer and the low refractive index layer stacked together; The uniformly layered stacker is used to uniformly divide and multiply the initial two-layer body into an upper and lower stacking structure.

5. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The post-processing includes a skin extrusion system; There are multiple non-uniform layer stackers; the multilayer body flowing out of the last non-uniform layer stacker flows into the surface layer extrusion system, and the surface layer extrusion system can form surface body layers on the upper and lower surfaces of the multilayer body respectively.

6. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The post-processing includes the multilayer body sequentially passing through an expanding die, a cooling and traction system, a winding and trimming system, and biaxial stretching.

7. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 1, characterized in that: The high refractive index layer is formed of a high refractive index optical resin, and the high refractive index optical resin can be doped with a high refractive index inorganic nanofiller or subjected to a stretching-induced molecular chain orientation crystallization treatment; The low refractive index layer is formed of a low refractive index optical resin, and a pore structure can be introduced by etching, stretching, or inducing phase separation.

8. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 4, characterized in that: The initial two-layer body is formed by a first extruder providing a first raw material and a second extruder providing a second raw material, which are respectively connected to an initial flow concentrator and flow out of the initial flow concentrator; The first raw material is used to form the high refractive index layer, and the second raw material is used to form the low refractive index layer.

9. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 4, characterized in that: The number of the uniform layer stackers and the number of the non-uniform layer stackers are both multiple; The uniform layer stackers are connected in series in sequence, and the non-uniform layer stackers are connected in series in sequence, and the output end of the last uniform layer stacker is connected to the input end of the first non-uniform layer stacker.

10. The method for preparing a multilayer optical film with controllable layer sequence distribution according to claim 5, characterized in that: Functional particles are added into the surface layer.

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