Vehicle-mounted head-up display optical film with light scattering function and preparation method thereof

Abstract

The present application belongs to the field of automobile head-up display technology, and relates to a vehicle-mounted head-up display optical film with light scattering function and a preparation method thereof. The present application adopts a heat-sensitive shape memory idea, utilizes the light-sensitive characteristics and shape memory function of a light-heat effect type shape memory material, and sets a dynamic scattering layer scattering part. When the front sunlight is irradiated, the scattering part is raised, so that the sunlight is scattered to other directions through the scattering effect of light. Further, the scattering layer substrate is set as an encapsulated scattering solution. The shape memory material in the scattering solution is deformed and curled when irradiated by sunlight, absorbs and reflects part of the light, thereby further reducing the penetration of sunlight into the display film into the driver's line of sight. Moreover, reflective particles and light-absorbing particles are added in the scattering solution, further reducing the penetration of sunlight into the display film, thereby preventing or reducing sunlight from directly entering the driver's eyes from multiple aspects, and further improving the safety of driving.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automotive head-up display, and particularly relates to a vehicle-mounted head-up display optical film with light scattering function and a preparation method thereof. BACKGROUND

[0002] This section is intended to provide background information to facilitate a better understanding of embodiments of the present application described in the claims. The description herein does not constitute admission of prior art.

[0003] Compared with traditional head-down displays (HDDs), vehicle-mounted head-up displays (HUDs) reduce the eye-off-the-road time (EoRT) by projecting virtual images into the driver's forward field of view (FoV). Due to the advantage in information acquisition cost, vehicle-mounted head-up displays are considered to have the potential to improve driving performance and safety. In addition, vehicle-mounted head-up displays play a positive role in the management of major and minor driving affairs. Since General Motors first introduced a vehicle-mounted head-up display in 1988, commercial vehicle-mounted head-up displays have been used in various mass-produced cars. It is predicted that by 2024, almost one-third of cars will be equipped with head-up display systems.

[0004] Although the head-up display provides great convenience for the driver and reduces safety hazards under normal light, the relative position of the car and the sun will change constantly as the driving direction of the vehicle changes. When the driving direction of a vehicle is opposite to the position of the sun, for example, in the morning and in the afternoon when the sun is low, in the morning when driving to the east, in the afternoon when driving to the west, or in any case when the sun is directly shining through the front windshield of the car and directly into the driver's eyes, the sunlight passing through the head-up display area of the windshield will directly enter the driver's eyes, causing the driver's eyes to be unable to open, the line of sight to be blocked, and the driving safety to be seriously affected. More seriously, if the driver needs to drive on a road in a certain direction for a long time, and the direction is the direction in which the sun is directly shining into the driver's eyes, the driver will drive for a long time in the glare of the sun, and the safety hazards are huge. Although many cars are equipped with sun visors, the driver needs to manually bend and adjust the sun visors to the appropriate angle to just block the sunlight in front during driving. The entire process requires the driver to force the steering wheel, and the driver needs to adjust the angle of the sun visor according to the angle of the sunlight, which is time-consuming and has very high safety hazards. Moreover, if the sunlight is directly shining into the eyes and the road conditions change, such as meeting, obstacles, sharp turns, and other situations that require concentration, the driver is not holding the steering wheel and constantly adjusting the sun visor, and cannot respond to the road conditions in time, which has a very high probability of causing accidents. Moreover, the sun visor will also block part of the driver's view, making the driver's field of view smaller, which is not conducive to timely understanding and judging the road conditions outside the car. On the other hand, the head-up display image under the sun's radiation has a significant decrease in image recognition, and even cannot be seen clearly. The driver cannot determine which direction to go, whether there is a fork or a turn ahead, and the distribution of the lanes. Under the superposition of multiple unfavorable factors such as temporary "blindness" of the driver due to the sun shining into the eyes and making the eyes unable to open, unclear head-up display image causing navigation failure, temporary brain blank due to not knowing the road conditions ahead, and the like, especially for inexperienced drivers, there will be hand and foot disorder, operation failure, and the like. Lightly, the driver will take a wrong road, which will affect the trip. Seriously, the driver will have a serious traffic accident, and the consequences are unpredictable.

[0005] Chinese invention patent application CN202211174763.9 discloses a windshield, a manufacturing method, a display device and a traffic equipment. Among them, the windshield comprises: a transparent substrate; a transmission-reflection film located on the transparent substrate and configured to reflect a part of incident light rays propagating to the transmission-reflection film and transmit another part of the incident light rays, wherein the transmission-reflection film comprises at least one first layer and at least one second layer arranged alternately, the refractive index n1 of the first layer ranges from 1.8 to 2.6, and the refractive index n2 of the second layer ranges from 1.2 to 1.8. The reflection and refraction of the incident light rays are realized by the different refractive indexes of the different layers of the transmission-reflection film. Chinese invention patent application CN202010930913.9 discloses a glare prevention method, device and equipment for a windshield, which collects related information of incident light rays irradiating on the windshield, including intensity, incident angle and irradiation area; analyzes the related information, distinguishes light ray categories according to the intensity and / or incident angle of the light rays, determines corresponding visual impact areas according to the irradiation area and the eye position of the driver, adjusts the light transmittance of the background theme based on the light ray categories and the visual impact areas, and achieves the glare prevention effect. Chinese invention patent application CN202311724126.9 discloses an automatic anti-glare method and device, a vehicle and a storage medium, which identifies the eye position of the driver and the light source information causing glare to the driver; determines the glare area on the front windshield according to the eye position, and determines the target parameters of the heads-up display system for anti-glare display in the glare area according to the light source information; and controls the heads-up display system to perform anti-glare display in the glare area according to the target parameters. The above-mentioned applications respectively prevent direct sunlight through the multi-layer structure of the windshield with different refractive indexes, or adjust the light transmittance of the heads-up display background by identifying the light ray categories and the impact area, or control the target parameters to control the heads-up display system to prevent glare. SUMMARY

[0006] The present application aims to solve the problems of image recognition degradation and safety hazards caused by the driver's line of sight being blocked when the heads-up display in the prior art encounters sunlight, proposes a brand-new anti-sunlight glare idea, provides a vehicle-mounted heads-up display optical film with light scattering function and a preparation method thereof, thereby further improving the safety of driving.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows.

[0008] A vehicle-mounted heads-up display optical film with light scattering function, the optical film comprises a dynamic scattering layer and a light reflection layer, the light reflection layer is a mixture of a thermoplastic material and a plasticizer, and the light reflection layer is wedge-shaped; the dynamic scattering layer comprises a dynamic scattering layer substrate and a scattering part, the scattering part is located on the side of the dynamic scattering layer substrate away from the light reflection layer, the side of the dynamic scattering layer substrate close to the light reflection layer is a plane and tightly adheres to the light reflection layer;

[0009] The scattering part is a plurality of light scattering points distributed in the dynamic scattering layer base, the scattering part is made of a thermal induced two-way shape memory polymer material without external force, a heat inducing agent capable of converting light energy into heat energy is coated on the side surface of the scattering part away from the light reflecting layer, the scattering part is convex when directly irradiated by sunlight, and returns to the original state when there is no sunlight.

[0010] The dynamic scattering layer base encapsulates a scattering solution, the scattering solution is a solution of a thermal induced two-way shape memory polymer material, the scattering solution is a transparent system when there is no sunlight irradiation, and the thermal induced two-way shape memory polymer material in the scattering solution is curled when irradiated by sunlight. The scattering solution can absorb and reflect part of the light when irradiated by sunlight, thereby further reducing the penetration of sunlight into the display film into the driver's line of sight.

[0011] The present application provides a dynamic scattering layer scattering part, which is convex when irradiated by sunlight from the front, thereby scattering sunlight to other directions through the scattering effect of light, preventing or reducing the direct irradiation of sunlight into the driver's eyes.

[0012] Preferably, the thermoplastic material is PVB.

[0013] In some embodiments of the present application, the heat inducing agent is a monatomic gold, carbon black, graphene or carbon nanotube coated on the surface of the scattering part.

[0014] In some embodiments, the light transmittance of the dynamic scattering layer is not less than 70%.

[0015] Specifically, the components of the scattering solution include 30%-50% thermal induced two-way shape memory material, 0.2%-0.8% heat inducing agent, 40%-50% plasticizer, 5%-6% dispersant and 3%-4% defoaming agent. The thermal induced two-way shape memory polymer material needs to add a heat inducing agent, i.e. a light induced heat material, to convert light energy into heat energy, and the thermal induced two-way shape memory material is deformed under the action of heat energy and forms a stable colloidal solution under the action of a dispersant.

[0016] In order to further enhance the reflection of sunlight, the dynamic scattering layer uniformly disperses light absorbing material particles and light reflecting material particles, so that the dynamic scattering layer itself has part of the light scattering function.

[0017] In some embodiments, the pyrogenic agent is selected from at least one of carbon nanoparticles, carbon nanotubes, carbon black, graphene, graphene oxide, graphite, carbon dots, single-atom gold, Ag nanomaterials, Pt nanoparticles, Al nanoparticles, CuS nanosheets, TiO2 nanoparticles, MoO3 quantum dots, Fe3O4, indocyanine green, Prussian blue, thiazole derivatives, and porphyrin rings.

[0018] In some embodiments, the thickness of the dynamic scattering layer is less than one-tenth of the thickness of the light reflecting layer, for example, it can be 0.05 mm.

[0019] In addition, the present application also provides a preparation method of a vehicle head-up display optical film with light scattering function, comprising the following steps:

[0020] S1: providing the thermotropic external force-free bidirectional shape memory high polymer material, processing it into a filament with a diameter of 10-20 μm, taking 30-50% of the processed thermotropic external force-free bidirectional shape memory high polymer material into 40-50% of a plasticizer, and then sequentially adding 5-6% of a dispersing agent, 0.2-0.8% of a pyrogenic agent, and 3-4% of an antifoaming agent, and stirring until a homogeneous scattering solution is obtained;

[0021] S2: encapsulating the scattering solution in a transparent encapsulating layer, wherein the scattering solution completely fills the encapsulating layer, and a dynamic scattering layer matrix is formed, and the encapsulating layer uses PVB resin as a main material;

[0022] S3: providing the thermotropic external force-free bidirectional shape memory high polymer material, heating it to a flow or semi-flow state, stirring it until it is uniform, obtaining a stable liquid scattering part, laying the dynamic scattering layer matrix, laying a layer of transparent adhesive film on the dynamic scattering layer matrix, coating the liquid scattering part on the surface of the adhesive film according to the distribution of the scattering points of the scattering part, then placing a plurality of carbon nanotubes on the surface of the coated scattering part, and placing the dynamic scattering layer matrix at room temperature until the liquid scattering part is cooled and shaped and adheres to the dynamic scattering layer matrix, forming a dynamic scattering layer;

[0023] S4: using a wedge-shaped polyvinyl butyral PVB film as a light reflecting layer, and flatly adhering it to a platform, placing it in a vacuum environment, and then pressing the dynamic scattering layer prepared in step S3 on the light reflecting layer, pressing each area of the dynamic scattering layer so that the light reflecting layer and the dynamic scattering layer are tightly adhered and have no bubbles or impurities, and thus the vehicle head-up display optical film is obtained.

[0024] Further, the adhesive film is a mixture of a thermoplastic material and a plasticizer, and the thermoplastic material is preferably PVB.

[0025] Further, in order to make the dynamic scattering layer itself have a part of light scattering function, the above step S1 further comprises:

[0026] The light-absorbing material microparticles and the light-reflecting material microparticles are ball-milled in a ball mill at a speed of 30-50 r / min for 30 min-60 min, and the scattering solution is added.

[0027] Further, the scattering part of the vehicle-mounted head-up display optical film has a diameter of 0.05 mm-0.1 mm, and the total area of the scattering part accounts for one-third to two-thirds of the area of one side of the dynamic scattering layer.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The present application adopts the heat-sensitive shape memory idea, utilizes the light-sensitive characteristics and shape memory function of the light-heat effect type shape memory material, through the setting of the scattering part of the dynamic scattering layer, when the front sunlight is irradiated, the scattering part is raised, thereby scattering the sunlight to other directions through the scattering effect of light, and further through the setting of the scattering layer matrix as the encapsulated scattering solution, the shape memory material in the scattering solution is deformed and curled when irradiated by sunlight, absorbs and reflects part of the light, thereby further reducing the penetration of sunlight into the display film into the driver's line of sight. And the light-reflecting particles and light-absorbing particles are pre-added in the scattering solution, further reducing the penetration of sunlight into the display film, thereby preventing or reducing the direct sunlight into the driver's eyes from multiple aspects, further improving the safety of driving. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings described herein are used to provide further understanding of the present application, constitute a part of the present application, and the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0031] Figure 1 is a structure schematic diagram of the vehicle-mounted head-up display optical film with light scattering function of the embodiment 1 of the present application;

[0032] Figure 2 is a structure schematic diagram of the vehicle-mounted head-up display optical film with light scattering function of the embodiment 1 of the present application when irradiated by sunlight;

[0033] Figure 3 is a scattering part schematic diagram of the vehicle-mounted head-up display optical film with light scattering function of the embodiment 1 of the present application;

[0034] Figure 4 is a test result diagram of the shape memory function repeatability and stability of the scattering part of the vehicle-mounted head-up display optical film with light scattering function of the embodiment 1 of the present application.

[0035] Among them, 1-light-reflecting layer, 2-dynamic scattering layer, 3-scattering part, 4-outer windshield, 5-inner windshield, 6-sealing layer, 7-scattering solution. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with embodiments and drawings, the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and do not limit the present application.

[0037] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there can be a middle element. When an element is referred to as "provided with" another element, it can be provided on the surface or inside of the element.

[0038] Unless otherwise explicitly indicated, in the entire specification and claims, the term "comprise" or its variants such as "contain" or "include" and the like will be understood to include the stated element or component, but not exclude other elements or components.

[0039] The present application aims at the problem that the image recognition degree of the head-up display in the prior art decreases when sunlight is encountered, and the safety hidden danger caused by the driver's line of sight being blocked. By using the light-sensitive characteristic and the shape memory function of the light-heat effect type shape memory material, a vehicle-mounted head-up display optical film with light scattering function and a preparation method thereof are provided, so as to further improve the safety of driving. The present application will be described below through specific embodiments.

[0040] Embodiment 1

[0041] This embodiment first provides a vehicle-mounted head-up display optical film with light scattering function, the structure of which is as shown in Figure 1 The optical film includes a dynamic scattering layer 2 and a reflective layer 1, the reflective layer 1 is a wedge-shaped PVB film; the dynamic scattering layer 2 includes a dynamic scattering layer substrate and a scattering part 3, the scattering part 3 is a plurality of light scattering points distributed in the dynamic scattering layer substrate, the scattering part 3 is made of a heat-induced type external force-free bidirectional shape memory polymer material, a heat-inducing agent capable of converting light energy into heat energy is covered on the side surface of the scattering part 3 away from the reflective layer 1, the scattering part 3 is convex when directly irradiated by sunlight, and returns to the original state when there is no direct sunlight. The dynamic scattering layer 2 is close to the outer windshield 4, and the reflective layer 1 is close to the inner windshield 5.

[0042] In some embodiments, in order to make the dynamic scattering layer 2 better fit with the light reflecting layer 1, the scattering part 3 is located on the side of the dynamic scattering layer 2 away from the light reflecting layer 1, the side of the dynamic scattering layer 2 close to the light reflecting layer 1 is flat and closely adheres to the light reflecting layer 1. The scattering part 3 is located on the outer side close to the windshield, and the light reflecting layer 1 is located on the inner side close to the driver.

[0043] The present application sets the scattering part 3 of the dynamic scattering layer 2, when it is irradiated by the sunlight from the front, the scattering part 3 protrudes, thereby scattering the sunlight to other directions through the scattering effect of light, preventing or reducing the direct sunlight into the driver's eyes. The area and distribution of the shape memory material of the scattering part 3 are important, too large area will affect the driver's view, too small area cannot effectively scatter the incident sunlight, and cannot achieve good effect. As shown in the figure, the scattering part 3 is a plurality of irregular dots uniformly distributed in the dynamic scattering layer matrix, the diameter of the scattering part 3 of the vehicle-mounted head-up display optical film in this embodiment is 0.08mm, and the total area of the scattering part 3 accounts for one-half of the area of one side of the dynamic scattering layer 2. The thickness of the scattering part is 0.02mm, and the thickness of the dynamic scattering layer matrix is 0.03mm. Figure 3

[0044] Alternatively, the scattering part 3 can be prepared by using a photothermal effect type shape memory polymer material. The photothermal effect type shape memory polymer material is to introduce a photo-thermal conversion material into a thermal-induced type shape memory polymer matrix without external force, increase its absorption of light and heat conduction, convert the absorbed light energy into heat energy, and then induce the thermal-induced type shape memory polymer material without external force to deform, thereby indirectly realizing the photo-induced type shape memory characteristics. Therefore, it can also be said that it belongs to the thermal-induced type shape memory material in essence. The photothermal effect type shape memory polymer material of the scattering part 3 includes a heat inducing agent and a thermal-induced type shape memory polymer material without external force. When the scattering part 3 is irradiated by sunlight, the heat inducing agent inside the scattering part 3 converts the light energy into heat energy after absorbing light, and the thermal-induced type shape memory polymer material without external force deforms under the action of heat energy, so that the side of the scattering part 3 close to the light irradiation shrinks, and the side far away from the light irradiation deforms less or does not deform, so that the scattering part 3 material is rolled up from the four sides to the middle, becoming a spherical particle, which scatters the incident sunlight to all directions. Further, the rolled-up scattering part 3 wraps the heat inducing agent in a smaller space, which is conducive to the accumulation of heat and the rise of temperature, further promoting the deformation of the material on the surface of the spherical particle far away from the heat inducing agent, so that the scattering part 3 is more curled and the scattering effect of sunlight is better.

[0045] ​The thermal type no external force bidirectional shape memory polymer material of the embodiment can select a heat shrinkage type shape memory polymer material with a heat response temperature of 0-70℃, such as liquid crystal elastomer, cross-linked crystalline polymer and its composite material. Generally, according to the preparation method, the bidirectional shape memory polymer under no external force can be divided into four categories: (1) thermoplastic polymer, (2) chemically cross-linked semi-crystalline polymer, (3) liquid crystal polymer, (4) layered polymer composite material. The cross-linked crystalline polymer refers to two interpenetrating network polymers arranged in each other; one of the network polymers is a shape memory polymer of a crystalline cross-linked polymer, and the other network polymer is a cross-linked elastic material. The crystalline cross-linked polymer is one or more of the shape memory polymers of polyurethane, polyethylene, poly-norbornene, trans-polyisoprene or styrene-butadiene copolymer; the cross-linked elastic material is one or more of polyurethane elastomer resin, SBS resin, propylene-butene copolymer, hard rubber or silicone rubber. Among them, the polyurethane can also select a shape memory polyurethane material polymerized from three monomer raw materials of polytetramethylene glycol (PTMG), 4,4-diphenyl methane diisocyanate (MDI) and chain extender, adjust the glass transition temperature Tg by raw material ratio to obtain shape memory polyurethane with different response temperatures, for example, the display film with different response temperatures can be set according to the use city, season and the like of the automobile, such as response temperature at 25℃, 35℃, 45℃, 55℃, etc. The thermal type no external force bidirectional shape memory material can also select a polymer material with bidirectional reversible shape memory effect with a single crystal thermosetting system (CN2015116304.1 Polymer with bidirectional reversible shape memory effect and preparation method thereof), which realizes reversible shape memory with high temperature amorphous phase as stress phase; that is, through the low temperature crystalline phase in the system after cross-linking, the reversible deformation of shape is realized with temperature change, which has the function of bidirectional memory of repeatedly memorizing two state shapes. The material contains at least one amorphous phase and one crystalline phase, wherein the glass transition temperature of the amorphous phase is higher than the melting temperature of the crystalline phase, and the difference is at least 20℃. The polymer bidirectional reversible shape function can realize the regulation of the proportion of two phases, cross-linking density, crystalline phase melting temperature and amorphous phase glass transition temperature under the premise that the glass transition temperature of the amorphous phase is higher than the crystalline melting temperature of the crystalline phase, so as to adapt to the needs of different application scenarios. Specifically, a certain amount of polyethylene glycol diacrylate and methyl methacrylate cyclohexyl ester (the mass ratio of PEGDA to CMA is 3:1) can be used, and benzoyl peroxide (its addition amount is 3% of the total mass of the system) is added, which is dissolved at 70℃, stirred uniformly and then poured into a sealed glass tank and solidified for 2-3h at 1℃. The shape memory function is realized by the following way: the polymer is heated to 156℃, stretched under the force of 1N, cooled to 56℃ under the tension, and the tension is removed. This process is a programmed deformation process.Then continue to cool to 0 ℃, heating to 56 ℃, this polymer can be repeated at 0 ℃ ~ 56 ℃ cold elongation and thermal contraction of the double shape memory phenomenon. Thermal induced type without external force bidirectional shape memory material can also be used semi-crystalline polymer, based on the self-nucleation effect of the construction of bidirectional shape memory elastomer, through the self-nucleation heat treatment process to realize the difference of polymer crystalline morphology, induce the formation of thickening lamella and original lamella with different melting points, so that the chemical crosslinking of semi-crystalline polymer exhibits excellent bidirectional shape memory behavior under no external force. Principle as follows: the bidirectional shape memory elastomer is prepared by semi-crystalline polymer through chemical crosslinking reaction. The elastomer in the shape fixing process, through the self-nucleation heat treatment process: first, the elastomer is heated to complete melting, then cooled to the crystallization temperature below the formation of crystalline phase, then heated to the self-nucleation temperature, most of the lamella in the crystalline phase of the elastomer melt, the unmelted lamella annealing at this temperature, the thickness of the lamella increases, the crystallization is more perfect, the melting point is improved, so that the network forms anisotropic structure. Then the elastomer is cooled to below the crystallization temperature, because of the existence of the crystal seed, the molten molecular chain can quickly crystallize to form the original lamella. Finally, the bidirectional shape memory elastomer is cycled under heating and cooling without external force, realizing the bidirectional reversible deformation. Thickening lamella is always unmelted in the subsequent heating process, so the difference of the internal crystalline structure of the bidirectional shape memory elastomer is maintained, two kinds of lamella (thickening lamella and original lamella) coexist, ensuring the bidirectional shape memory effect of the bidirectional shape memory elastomer. The specific preparation method is: poly(ε-caprolactone) diacrylate, tetra(3-mercaptopropionic acid) pentaerythritol ester and triethylamine are dissolved in dimethylformamide, which together constitute the prepolymer; in the mixed solution, the concentration of poly(ε-caprolactone) diacrylate is 0.5 g / ml, the molar ratio of double bond in poly(ε-caprolactone) diacrylate to mercapto group in tetra(3-mercaptopropionic acid) pentaerythritol ester is 1:1; triethylamine accounts for 10wt% of the total mass of the prepolymer; the mixed solution is transferred to the mold, the crosslinking is completed at 80℃ for 8h, after demolding, vacuum drying at 40℃ for 24h, semi-crystalline crosslinked polymer, i.e. elastomer, is obtained, and the crystallization temperature of the elastomer is 20℃. Self-nucleation heat treatment process: the elastomer is heated to 70℃, isothermal for 3 minutes to completely melt; a constant strain of 10%-97% relative to the original length of the elastomer is applied, while cooling to 10℃; isothermal for 20 minutes, so that the elastomer forms a crystalline phase; keep constant strain, heat to the self-nucleation temperature (between 40-45℃), isothermal annealing treatment for 5 minutes, so that part of the lamella in the crystalline phase melts, the unmelted lamella thickens to form thickening lamella; then cool to 10℃ again, isothermal for 20 minutes, so that the crystallizable segment of the molten part crystallizes to form original lamella, finally the bidirectional shape memory elastomer is obtained. Bidirectional memory behavior characterization: the bidirectional shape memory elastomer is subjected to a cyclic temperature program between Thigh and Tlow, realizing reversible thermal contraction and cold elongation deformation.(1) the permanent shape of the elastomer is shape A, and the elastomer is subjected to a self-nucleation heat program while being pre-stretched, and is deformed into shape B; (2) the bi-directional shape memory elastomer fixed in shape B is placed in an environment of Thigh to achieve thermal contraction and transform into shape C; (3) the bi-directional shape memory elastomer with shape C is placed in an environment of Tlow to achieve cold elongation and transform into shape D; (4) a cyclic temperature program is carried out between Thigh and Tlow, and the bi-directional shape memory elastomer realizes reversible switching between shape C and shape D. The temperature range of the self-nucleation temperature is controlled in the range of 40-45℃, the temperature range of Thigh is controlled in the range of 39℃-49℃, and the temperature range of Tlow is controlled in the range of 10℃, so that it can respond between 10℃-49℃. This embodiment can also use polycaprolactone diacrylate prepolymer (PCLDA) with gradient molecular weight and n-butyl acrylate (BA) to prepare a series of free external force bi-directional shape memory materials with wide melting transition by free radical copolymerization and crosslinking. This material realizes the free external force bi-directional shape memory behavior of the material through stress-induced crystallization and self-nucleation behavior. The thermally induced free external force bi-directional shape memory material of this embodiment is preferably the above-mentioned polymer material with a single crystal thermoset system with a bi-directional reversible shape memory effect. This material has a wider range of applications.

[0046] According to the principle of photo-thermal effect type shape memory, the heat-inducing agent should be selected from materials with photo-thermal effect. The heat-inducing agent is coated on the surface of the scattering part 3. The heat-inducing agent can be selected from any organic or inorganic photo-thermal material. Specifically, it can be selected from carbon nanoparticles, carbon nanotubes, carbon black, graphene, graphene oxide, graphite, carbon dots, single-atom gold, Ag nano-materials, Pt nanoparticles, Al nanoparticles, CuS nanosheets, TiO2 nanoparticles, MoO3 quantum dots, Fe3O4, indocyanine green, Prussian blue, thiazole derivatives, and porphyrin rings. Among them, single-atom gold refers to a nano-material composed of a single gold atom. Due to its special structure and electronic properties, it has unique photo-thermal effect characteristics. This is mainly due to the surface plasmon resonance (SPR) caused when light is incident on the surface of single-atom gold, which excites the surface plasmon oscillation, thereby absorbing light energy and converting it into heat energy, causing the surface temperature of single-atom gold to rise. Due to the very small size of single-atom gold, its surface area is very large relative to its volume, so the photo-thermal effect is very strong. Different heat-inducing agents have different photo-thermal conversion efficiencies. For example, Jiangsu Xianfeng Nanometer Material Technology Co., Ltd. has multiple series of products with different performance parameters.

[0047] Table 1 Performance parameters of photo-thermal conversion materials of Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.

[0048] Product number Product name Temperature rise (measured data) XFK01 Titanium carbide (Ti3C2Tx) MXene multi-layer nanosheet 52℃ XFK41-1 Titanium carbide (Ti3C2Tx) MXene nanosheet 52℃ XF019-1 Single-layer graphene dispersion 60℃ XFM01 Multi-walled carbon nanotube 52℃ XFS22 Ultra-high purity large specific surface area single-walled carbon nanotube 56℃ XFD01 Double-walled carbon nanotube 52℃ XFP03 Ordered mesoporous carbon CMK-3 41℃ XFP12 Mesoporous carbon sphere 38℃ XF207 Black phosphorus nanosheet dispersion 40℃ XF283 Violet phosphorus crystal powder 42℃

[0049] The heat generating agent of the scattering part 3 in the embodiment is selected as XFS22 product of Jiangsu Xianfeng Nanometer Material Technology Co., Ltd., i.e. super-high-purity large specific surface area single-walled carbon nanotube. In order to improve the photo-thermal conversion efficiency of the heat generating agent, the incident sunlight is converted into heat energy as quickly as possible to drive the deformation of the thermal type two-way shape memory material without external force, and the time of the driver affected by the sunlight is reduced. In the embodiment, the heat generating agent is covered on the surface of the scattering part 3 close to the front of the vehicle, so that the heat generating agent is densely distributed on the side of the scattering part 3 under light. The heat generated after the heat generating agent absorbs light is locked on the surface of the side of the scattering part 3 under light, so that the surface of the side of the scattering part 3 under light is rapidly heated to the thermal response temperature, without the need to heat the whole scattering part 3, so as to improve the photo-thermal conversion efficiency, generate and accumulate more heat more quickly, and improve the response speed of the display film to light. The larger the specific surface area of the heat generating agent is, the higher the photo-thermal conversion efficiency is, and the more the heat generating agent is, the more the heat generated is. The particle size of the heat generating agent in the embodiment is 1 nm-50 nm. In actual application, the amount of the heat generating agent can be controlled according to the specific circumstances. The more the amount of the heat generating agent is, the higher the photo-thermal conversion efficiency and speed are, but the problem of light transmittance may be caused, which needs to be reasonably designed according to the actual situation. However, in general, the light transmittance of the dynamic scattering layer should not be less than 70%. The heat generating agent of the scattering part 3 in the embodiment is selected as carbon nanotube.

[0050] The shape memory repeatability and stability test of the scattering part 3 prepared in the embodiment is shown in Table 2. Figure 4 Specifically, the temperature monitoring device such as thermometer, temperature sensor and stress meter is arranged at the scattering part 3, the same scattering part 3 sample is placed under the sunlight for different time, the temperature change under different time is recorded, and the stress change of the optical film sample under different temperature is observed to evaluate the stability of the shape memory effect. As shown in the figure, after multiple irradiation, the scattering part 3 can repeatedly curl and stretch between 0℃-56℃, realize light scattering effect, and has good performance stability. The temperature change of the scattering part 3 under different irradiation time is shown in Table 2. Because the sun is high at noon, the sunlight generally does not directly irradiate the eyes of the driver, so the sunlight at 9 o'clock in the morning or 4 o'clock in the afternoon is used for the experiment in the embodiment.

[0051] Table 2 Temperature change of the scattering part under different irradiation time

[0052] Irradiation time / s 10 50 1 2 3 4 5 6 Scattering part temperature rise / °C 2 4 7 10 16 26 39 55

[0053] In order to further enhance the light scattering effect, in some embodiments, the entire dynamic scattering layer 2 can be provided with uniformly dispersed light-absorbing particles and light-reflecting particles to absorb and reflect part of the light. That is, the scattering part 3 and the body of the dynamic scattering layer substrate can be provided with uniformly dispersed light-absorbing particles and light-reflecting particles. When the scattering part 3 is irradiated by sunlight, due to the limited depth of light irradiation, the light is irradiated on the surface of the scattering part 3, the surface of the heat agent rapidly absorbs the light energy and converts it into heat energy, and transmits it to the heat-induced two-way shape memory polymer of the scattering part 3, causing the material on the side close to the heat agent to shrink first, while the unirradiated side deforms less or remains unchanged. The contraction side pulls the material on the retained side upwards, causing the entire scattering part 3 to curl into a ball-like structure. At this time, the curled scattering part 3 scatters sunlight in all directions, and the light-absorbing particles and light-reflecting particles in the scattering part 3 also absorb and reflect part of the sunlight, reducing the amount of sunlight entering the driver's eyes and reducing the impact of sunlight on the driver.

[0054] In order to further enhance the light scattering effect, in some embodiments, the dynamic scattering layer substrate is encapsulated with a scattering solution 7, which is a solution of heat-induced two-way shape memory polymer material cut into 10-20 μm diameter filaments and uniformly dispersed in its plasticizer.

[0055] The scattering solution 7 is a transparent system without sunlight irradiation, and when irradiated by sunlight, the heat-induced two-way shape memory polymer in the scattering solution 7 curls into light-absorbing particles or light-reflecting particles uniformly dispersed in the solution 7, making the scattering solution 7 a stable colloidal solution. Without sunlight irradiation, the heat-induced two-way shape memory material is fully stretched in the solution under the action of the plasticizer, and the scattering solution 7 is a transparent system. When irradiated by sunlight, the heat agent in the solution absorbs light intensity, converts light into heat energy, and transmits heat to the heat-induced two-way shape memory material, causing the heat-induced two-way shape memory material to curl into light-absorbing particles or light-reflecting particles uniformly dispersed in the colloidal solution under the action of the dispersant. The shape memory material in the scattering solution 7 can undergo phase separation under sunlight irradiation, forming light-absorbing particles or light-reflecting particles that can be used to absorb and reflect part of the light, thereby further reducing the penetration of sunlight into the driver's line of sight.

[0056] It should be understood that the heat-induced two-way shape memory material described above is a material that has been prepared and shaped in advance and can be directly applied to the scattering part 3 or the scattering solution 7 of the present embodiment.

[0057] The selection of the light-heat effect type shape memory polymer material in the dynamic scattering layer 2 scattering solution 7 is the same as the selection of the light-heat effect type shape memory polymer material in the scattering part 3 described above. The components of the scattering solution 7 include 39.4% of the heat-induced type two-way shape memory material without external force, 0.6% of the heat generator, 50% of the plasticizer, 6% of the dispersant, and 4% of the defoaming agent. The heat generator selected in this embodiment is a single-atom gold. The selection of the heat generator here is consistent with the selection of the heat generator in the scattering part 3 described above, and graphite, carbon nanoparticles, carbon nanotubes, etc. can also be selected. The heat-induced type two-way shape memory polymer material can be any polymer material that is sensitive to heat, shrinks when heated, and is soluble. As a component of the dynamic scattering layer 2, the heat-induced type two-way shape memory polymer material needs to be added with a heat generator, i.e., a light-induced heat material, to convert light energy into heat energy. The heat-induced type two-way shape memory material deforms under the action of heat energy and forms a stable colloidal solution under the action of the dispersant.

[0058] In order to further enhance the reflection of sunlight, the dynamic scattering layer 2 is uniformly dispersed with light-absorbing material particles and light-reflecting material particles. The dynamic scattering layer 2 itself has a part of the light scattering function.

[0059] Correspondingly, the embodiment also provides a preparation method of a vehicle-mounted head-up display optical film with a light scattering function, including the following steps:

[0060] Preparation of the dynamic scattering layer 2

[0061] First, the dynamic scattering layer substrate is prepared:

[0062] S1: Provide the heat-induced type two-way shape memory polymer material described above, process it into a filament with a diameter of 10-20 μm, add 39.4% of the heat-induced type two-way shape memory polymer material processed above into 50% of the plasticizer, and then sequentially add 6% of the dispersant, 0.6% of the carbon nanoparticle heat generator, and 4% of the defoaming agent. Stir at the dissolution temperature until it is completely dissolved into a transparent and stable scattering solution 7. The dispersant can be a metal soap dispersant, such as a metal salt of a higher fatty acid, which is called a metal soap, such as barium stearate (BaSt), zinc stearate (ZnSt), calcium stearate (CaSt), and other stearate soaps such as cadmium stearate (CdSt), magnesium stearate (MgSt), copper stearate (CuSt), etc. The defoaming agent can be selected from alcohol, fatty acid and fatty acid ester, amide, phosphate ester, organosilicon, polyether, and polyether-modified polysiloxane defoaming agents, etc.

[0063] S2: encapsulate the scattering solution 7 in a transparent encapsulation layer 6, the scattering solution 7 completely fills the transparent encapsulation layer 6, forming a dynamic scattering layer matrix; here, in order to prevent bubbles from affecting the line of sight, the scattering solution 7 should completely fill the encapsulation layer 6, so that the entire dynamic scattering layer matrix is a uniform transparent structure. The encapsulation layer 6 can be a transparent hard material or a transparent soft material. For a soft encapsulation layer 6, attention should be paid to the flatness when it is bonded with the light-reflecting layer 1 in the next step, and the liquid in the encapsulation layer 6 should uniformly adhere to the light-reflecting layer 1 without deformation after the entire display film is stood up. PVB resin is used as the main material for the encapsulation layer;

[0064] Then the preparation of the dynamic scattering layer 2 is carried out.

[0065] S3: provide the above-mentioned thermotropic two-way shape memory polymer material without external force, heat the thermotropic two-way shape memory polymer material to a flow or semi-flow state, stir uniformly to obtain a stable liquid scattering part, lay the dynamic scattering layer matrix prepared in step S2, lay a layer of transparent adhesive film on the dynamic scattering layer matrix, the adhesive film is a mixture of thermoplastic material and plasticizer, the thermoplastic material is PVB, apply the liquid scattering part to the surface of the adhesive film according to the distribution of the scattering part 3 scattering points, then place a plurality of carbon nanotubes on the surface of the scattering part 3, place the dynamic scattering layer matrix at room temperature and stand until the liquid scattering part 3 cools and sets and adheres to the dynamic scattering layer matrix, forming a dynamic scattering layer 2; here, carbon nanotubes are selected as the heating agent, in order to improve the light-heat conversion efficiency, the carbon nanotubes are arranged on the surface of the scattering part 3, for particulate or powdered heating agents, the heating agent can be directly covered on the surface of the scattering part 3 in a scattering manner, this step should be carried out before the liquid scattering part solidifies, so that the heating agent is solidified with the liquid scattering part to prevent the heating agent from falling off. The proportion of the heating agent in the scattering part 3 is 0.4%.

[0066] B, preparation of an optical display film

[0067] S4: use a polyvinyl butyral (PVB) film as the light-reflecting layer 1 and adhere it flat on a platform, place it in a vacuum environment, then press the dynamic scattering layer 2 prepared in step S3 onto the light-reflecting layer 1, press each area of the dynamic scattering layer 2 so that the light-reflecting layer 1 and the dynamic scattering layer 2 are tightly adhered and free of bubbles or impurities, turn on the vacuum heating to make the light-reflecting layer 1 and the dynamic scattering layer 2 fully bonded, if necessary, a certain pressure can be applied, when the pressure is applied, the structure of the dynamic scattering layer 2 should not be damaged, and the vehicle-mounted head-up display optical film is obtained.

[0068] The preparation method of the wedge-shaped polyvinyl butyral (PVB) film can adopt the existing disclosed technology, and the specific process is as follows: a hot press forming process is adopted, including the following steps: S1, placing the PVB raw material between two protective films and then placing it in a preheated mold; or, placing the first protective film of the two protective films in the preheated mold first, then placing the PVB raw material on the first protective film, and finally placing the second protective film of the two protective films on the PVB raw material; wherein the material of the two protective films can be a material with a certain hardness relative to the softened PVB film, which can be a non-stick coating coated or sprayed on a high-temperature-resistant substrate. Preferably, the material can be a glass fiber substrate and a Teflon coating. The thickness of the two protective films can be 0.1-1 mm respectively, and the thickness of the two protective films can be preferably 0.1-0.25 mm respectively. S2, the mold is closed; S3, the mold is pressurized and heated until the required temperature is reached. The pressure range of this step can be 10-1 MPa, and the pressure range can be preferably 20-30 MPa. The heating time to the required temperature is 20-180 seconds, and the required time is preferably 60-120 seconds. S4, the formed PVB film is taken out together with the two protective films; S5, the formed PVB film is cooled; S6, the two protective films are removed, and the PVB film for HUD is obtained. Wherein, the cross-sectional shape of the obtained PVB film for HUD in one direction is wedge-shaped. That is, the obtained PVB film can have a cross-sectional shape in one direction which is wedge-shaped, like the PVB film obtained by an extrusion forming process. Preferably, the cross-sectional shape of the obtained PVB film for HUD in one direction is wedge-shaped.

[0069] It is worth noting that "providing" in this embodiment can be any way to obtain the target material, such as preparation, procurement, customization, etc.

[0070] In step S3, the light-heat effect type shape memory polymer material of the scattering part 3 is shaped into a flat shape under ordinary light, and after being combined with the reflective layer 1 to form a head-up display film, it is installed on the car. In actual use, when the sun shines on the display film in front of the car, as shown in Figure 2As shown, the scattering part 3 of the dynamic scattering layer 2 is irradiated by sunlight, and due to the limited depth of light irradiation, the light-heat effect type shape memory polymer material on the side of the dynamic scattering layer 2 facing the sunlight absorbs sunlight and converts it into heat energy through the carbon nanoparticle heat generating agent under the action of sunlight, and the heat energy is transferred to the heat-induced type shape memory polymer material without external force, causing the heat-induced type shape memory polymer material without external force to shrink and deform. The side that is not irradiated deforms less or remains unchanged, so that the entire scattering part 3 curls and forms a spherical structure. At this time, the curled scattering part 3 scatters sunlight in all directions, and the light-absorbing particles and light-reflecting particles in the scattering part 3 also absorb and reflect part of the sunlight, reducing the amount of sunlight entering the driver's eyes and reducing the impact of sunlight on the driver. When the sunlight disappears, the light-heat effect type shape memory polymer material of the scattering part 3 has no sunlight irradiation, the heat energy decreases, and the scattering part 3 returns to the original flat state.

[0071] Further, in order to make the dynamic scattering layer 2 itself have a part of light scattering function, the above step S1 further comprises:

[0072] The light-absorbing material particles and the light-reflecting material particles are ball milled in a ball mill at a speed of 30-50 r / min for 30-60 min, and the scattering solution 7 is added.

[0073] The heads-up display optical display film of the present embodiment is used by arranging the above prepared heads-up display optical display film between the outer windshield 4 and the inner windshield 5 of the front windshield of the vehicle, and ensuring that the pressing is flat and there is no bubble or impurity between the layers, ensuring a good view for the driver.

[0074] Example 2

[0075] In this embodiment, the amount of heat generating agent added to the scattering part 3 is adjusted based on Example 1, and the proportion of heat generating agent added to the scattering part 3 is 0.8%.

[0076] Example 3

[0077] In this embodiment, the amount of heat generating agent added to the scattering part 3 is adjusted based on Example 1, and the proportion of heat generating agent added to the scattering part 3 is 0.2%.

[0078] Example 4

[0079] In this embodiment, the amount of heat generating agent added to the scattering part 3 is adjusted based on Example 1, and the proportion of heat generating agent added to the scattering part 3 is 0.6%.

[0080] The present application adjusts the amount of the scattering part 3 heat agent added, the irradiation time by setting different experiments, and sets a blank experiment, the blank experiment uses a common PVB display film without a dynamic scattering part 3 as a blank sample, and the display film obtained from the formula of example 1, example 2, example 4 of the present application is respectively arranged in the front windshield of a car, and the sunlight is irradiated from a fixed distance, the light signal is received at the position of the driver's eyes, the same optical film sample is repeatedly irradiated and stopped by using sunlight, the light transmittance of the optical film sample under different parameters is observed, and the experimental results are compared as follows.

[0081] The formula of example 3 and example 4 obtains display films and common PVB display films, which are respectively arranged in the front windshield of a car, and the sunlight is irradiated from a fixed distance, the light signal is received at the position of the driver's eyes, the same optical film sample is repeatedly irradiated and stopped by using sunlight, the light transmittance of the optical film sample under different parameters is observed, and the experimental results are compared as follows.

[0082] Table 3 Influence of scattering solution formula on total light transmittance of display film

[0083] Shape memory polymer material / % Plasticizer / % Pyrogenic agent / % Dispersing agent / % Defoaming agent / % Scattering part pyrogenic agent addition amount / mm Total light transmittance / & Example 1 39.4 50 0.6 6 4 0.4 80 Example 2 39.4 50 0.6 6 4 0.8 60 Example 3 39.4 50 0.6 6 4 0.2 90 Example 4 39.4 50 0.6 6 4 0.6 75

[0084] It can be seen from the comparison data in table 3 that the amount of the shape memory material is not the more the better, too much addition of the shape memory material on one hand causes the high polymer to shrink after light irradiation and easily form blocks, which cannot be well dispersed in the solution, and the light scattering effect is greatly reduced, and if the amount is too small, not enough particles can be formed, and the light scattering effect is not ideal. The amount of the scattering part 3 heat agent is also not the more the better, too much heat agent will affect the total light transmittance of the film, therefore, the best example should be example 4.

[0085] Example 5

[0086] In this embodiment, the diameter of the scattering part 3 of the head-up display optical film for vehicle is 1mm, and the total area of the scattering part 3 accounts for one half of the area of one side of the dynamic scattering layer 2.

[0087] Example 6

[0088] In this embodiment, the diameter of the scattering part 3 of the head-up display optical film for vehicle is 0.5mm, and the total area of the scattering part 3 accounts for two thirds of the area of one side of the dynamic scattering layer 2.

[0089] The display films obtained from the formula of example 4, example 5 and example 6 are arranged in the front windshield of a car, the sunlight is irradiated from a fixed distance, the light signal is received at the position of the driver's eyes, and the experimental results are compared as follows.

[0090] Table 4 Influence of scattering part diameter and area on total light transmittance of display film

[0091] Scattering part diameter / mm Scattering part area ratio Total light transmittance Example 4 0.8 Half 80% Example 5 1 Half 88% Example 6 0.5 Two-thirds 78%

[0092] As can be seen from the comparative data in Table 4, the setting of the scattering part 3, for example, the diameter and total area ratio of the scattering part 3, has a great influence on the light transmittance of the display film. The larger the diameter of the point-like scattering part 3 and the sparser the distribution, the lower the scattering effect and the higher the total light transmittance. The smaller the diameter of the scattering part 3 and the denser the distribution, the lower the total light transmittance of the display film and the better the anti-glare effect. Therefore, the optimal design of the scattering part 3 should be Example 6, the diameter of the scattering part 3 is 0.5 mm, and the total area of the scattering part 3 accounts for two-thirds of the area of one side of the dynamic scattering layer 2.

[0093] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0094] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements to part of the technical features

[0095] And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A head-up display optical film for a vehicle having a light scattering function, characterized by, The optical film comprises a dynamic scattering layer and a light reflection layer, the light reflection layer is a mixture of thermoplastic material and plasticizer, the light reflection layer is wedge-shaped; the dynamic scattering layer comprises a dynamic scattering layer substrate and a scattering part, the scattering part is located on the side of the dynamic scattering layer substrate away from the light reflection layer, the side of the dynamic scattering layer substrate close to the light reflection layer is a plane and closely adheres to the light reflection layer; The scattering part is a plurality of light scattering points distributed in the dynamic scattering layer substrate, the scattering part is made of thermotropic two-way shape memory polymer material without external force, and a pyrogenic agent capable of converting light energy into heat is coated on the surface of the scattering part away from the light reflection layer, the scattering part is convex when directly irradiated by sunlight and returns to the original state when there is no sunlight; The dynamic scattering layer substrate encapsulates a scattering solution, the scattering solution is a solution of thermotropic two-way shape memory polymer material, the scattering solution is a transparent system when there is no sunlight, and the thermotropic two-way shape memory polymer material in the scattering solution curls when irradiated by sunlight.

2. The on-vehicle head-up display optical film having a light scattering function according to claim 1, characterized by, The thermoplastic material is PVB.

3. The on-vehicle head-up display optical film having a light scattering function according to claim 1, characterized by The light transmittance of the dynamic scattering layer is not less than 70%.

4. The on-vehicle head-up display optical film having a light scattering function according to claim 1, characterized by, The components of the scattering solution include 30%-50% thermotropic two-way shape memory material, 0.2%-0.8% pyrogenic agent, 40%-50% plasticizer, 5%-6% dispersant, and 3%-4% defoaming agent.

5. The on-vehicle head-up display optical film having a light scattering function according to claim 1, characterized by The pyrogenic agent is selected from at least one of carbon nanoparticles, carbon nanotubes, carbon black, graphene, graphene oxide, graphite, carbon dots, monatomic gold, Ag nano-materials, Pt nanoparticles, Al nanoparticles, CuS nanosheets, TiO2 nanoparticles, MoO3 quantum dots, Fe3O4, indocyanine green, Prussian blue, thiazole derivatives, and porphyrin rings.

6. The method of producing a head-up display optical film for a vehicle with a light scattering function according to claim 1, characterized by, The method comprises the following steps: S1: providing the thermotropic two-way shape memory polymer material, processing it into a filament with a diameter of 10-20 μm, taking 30%-50% of the processed thermotropic two-way shape memory polymer material, adding 40%-50% plasticizer, and then sequentially adding 5%-6% dispersant, 0.2%-0.8% pyrogenic agent, and 3%-4% defoaming agent, and stirring until a homogeneous scattering solution is obtained; S2: encapsulating the scattering solution in a transparent encapsulation layer, the scattering solution completely fills the encapsulation layer, forming a dynamic scattering layer substrate; S3: providing the thermotropic two-way shape memory polymer material, heating it to a flow or semi-flow state, stirring until uniform, obtaining a stable liquid scattering part, laying the dynamic scattering layer substrate, laying a layer of transparent adhesive film on the dynamic scattering layer substrate, coating the liquid scattering part on the surface of the adhesive film according to the distribution points of the scattering part, then covering a layer of pyrogenic agent on the surface of the coated scattering part, and placing the dynamic scattering layer substrate at room temperature until the liquid scattering part is cooled and shaped and adheres to the dynamic scattering layer substrate, forming a dynamic scattering layer. S4: a wedge-shaped polyvinyl butyral PVB film is used as a reflective layer and is attached to the platform flatly, and is placed in a vacuum environment, then the dynamic scattering layer prepared in step S3 is laminated on the adhesive film, and each area of the dynamic scattering layer is pressed so that the reflective layer and the dynamic scattering layer are tightly attached and free of bubbles or impurities, thereby obtaining the vehicle head-up display optical film.

7. The preparation method according to claim 6, characterized in that, The adhesive film in step S3 is a mixture of a thermoplastic material and a plasticizer.

8. The preparation method according to claim 7, characterized in that, The thermoplastic material is PVB.

9. The production method according to claim 8, characterized by, The scattering part of the vehicle head-up display optical film has a diameter of 0.05mm-0.1mm, and the total area of the scattering part accounts for one-third to two-thirds of the area on one side of the dynamic scattering layer.

Images