Reflective film and windshield

Abstract

The utility model discloses a reflecting film and a windshield, and relates to the technical field of optical projection, and the reflecting film comprises a low-refractive-index dielectric layer and a high-refractive-index dielectric layer which are stacked in sequence; wherein the low-refractive-index dielectric layer is a silicon dioxide film layer with a porous structure, the refractive index of the low-refractive-index dielectric layer is inversely proportional to the porosity of the low-refractive-index dielectric layer, and the porosity refers to the proportion of the volume of pores in the film layer in the volume of the film layer. The silicon dioxide film layer of the porous structure is used as the low-refractive-index medium layer, the refractive index difference value of all media in the reflecting film can be increased by reducing the refractive index of the low-refractive-index medium, the film system of the reflecting film is simpler, the thickness and the preparation process of the reflecting film are easier to control, and the application range is wider. The windshield using the reflecting film has a better reflecting effect on P polarized light, so that the image display effect of a head-up display system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical projection, and more specifically, to a reflective film and a windshield. Background Art

[0002] In-vehicle head-up display (HUD) is a technology that projects information onto the windshield of the vehicle, and the information is reflected by the windshield to the human eye, so that the driver perceives it as a virtual image in front of him. Therefore, in a vehicle equipped with a head-up display function, the windshield needs to have reflection and imaging capabilities in addition to the common functions of safety protection and sight guarantee.

[0003] Generally, a reflective layer is provided in the windshield to enhance the light reflecting ability of the windshield. Therefore, it is very important to simplify the structure of the reflective film while reducing the ghosting rate of the windshield. Utility Model Content

[0004] Based on the above background, the present application proposes a reflective film and a windshield.

[0005] In the first aspect, an embodiment of the present application provides a reflective film, comprising: a low-refractive index medium layer and a high-refractive index medium layer stacked in sequence; wherein the low-refractive index medium layer is a silica film layer with a porous structure, and the refractive index of the low-refractive index medium layer is inversely proportional to the porosity of the low-refractive index medium layer, and the porosity refers to the proportion of the volume of pores in the film layer to the volume of the film layer.

[0006] Optionally, the refractive index of the low-refractive-index medium layer is 1.2.

[0007] Optionally, the refractive index of the high refractive index medium layer is 2.32.

[0008] Optionally, the reflective film further includes a medium refractive index medium layer, and the medium refractive index medium layer is stacked on a side of the high refractive index medium layer away from the low refractive index medium layer.

[0009] Optionally, the refractive index of the medium refractive index medium layer is 1.67.

[0010] Optionally, the reflective film further comprises a metal layer, and the metal layer is stacked and arranged on a side of the high refractive index medium layer away from the low refractive index medium layer.

[0011] Optionally, the reflective film includes a plurality of low-refractive index medium layers and a plurality of high-refractive index medium layers, and each of the low-refractive index medium layers and each of the high-refractive index medium layers are alternately stacked in sequence.

[0012] In the second aspect, an embodiment of the present application also provides a windshield, comprising: a stacked inner glass, an outer glass and the reflective film as described above, wherein the inner glass is arranged on a side of the reflective film close to the low refractive index medium layer, and the outer glass is arranged on a side of the reflective film close to the high refractive index medium layer.

[0013] Optionally, the windshield further includes a bonding layer, and the reflective film is laminated with the inner glass or the outer glass via the bonding layer.

[0014] Optionally, the windshield further includes a functional layer, and the functional layer is stacked between the outer glass and the reflective film.

[0015] Therefore, the present application provides a reflective film and a windshield, wherein the reflective film comprises: a low-refractive index medium layer and a high-refractive index medium layer stacked in sequence; wherein the low-refractive index medium layer is a silicon dioxide film layer with a porous structure, and the refractive index of the low-refractive index medium layer is inversely proportional to the porosity of the low-refractive index medium layer, and the porosity refers to the proportion of the volume of the pores in the film layer to the volume of the film layer. By using a silicon dioxide film layer with a porous structure as a low-refractive index medium layer, the present application can increase the difference in the refractive index of each medium in the reflective film by reducing the refractive index of the low-refractive index medium, so that the film system structure of the reflective film is simpler, and its thickness and preparation process are easier to control, and the windshield using the reflective film has a better reflection effect on P-polarized light, thereby improving the image display effect of the head-up display system.

[0016] Other features and advantages of the embodiments of the present application will be described in the subsequent description, and partly become apparent from the description, or can be understood by practicing the embodiments of the present application. The purposes and other advantages of the embodiments of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram showing the relationship between the reflectivity and the incident angle when P-polarized light and S-polarized light are incident from air to glass.

[0019] Figure 2 A schematic diagram showing light emitted by a head-up display system incident on a windshield is shown.

[0020] Figure 3 A schematic structural diagram of a reflective film proposed in an embodiment of the present application is shown.

[0021] Figure 4 A schematic diagram showing the relationship between the refractive index and porosity of a low-refractive-index medium layer in a reflective film proposed in this application example is shown.

[0022] Figure 5 A schematic structural diagram of another reflective film proposed in an embodiment of the present application is shown.

[0023] Figure 6 A curve diagram showing the reflectivity and transmittance of a light beam incident on the reflective film provided in an embodiment of the present application is shown.

[0024] Figure 7 A schematic structural diagram of another reflective film proposed in an embodiment of the present application is shown.

[0025] Figure 8 A curve diagram showing the reflectivity and transmittance of another type of light when incident on the reflective film proposed in an embodiment of the present application is shown.

[0026] Fig. 9 A schematic structural diagram of another reflective film proposed in an embodiment of the present application is shown.

[0027] Fig.10 A curve diagram showing the reflectivity and transmittance of another type of light when incident on the reflective film proposed in an embodiment of the present application is shown.

[0028] Fig.11 A schematic structural diagram of a windshield proposed in an embodiment of the present application is shown.

[0029] Fig.12 A schematic structural diagram of another windshield proposed in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0030] In order to make those skilled in the art better understand the present application scheme, the technical scheme in the present application embodiment will be clearly and completely described below in conjunction with the drawings in the present application embodiment. Obviously, the described embodiment is only a part of the present application embodiment, rather than all the embodiments. The components of the present application embodiment usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application for protection, but merely represents the selected embodiment of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0031] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0032] In the head-up display system, the optical engine emits light containing information, and the light is reflected from the windshield at a specific incident angle. Generally, the incident angle of the light emitted by the optical engine ranges from 50° to 70°, and usually the light will hit the windshield at an incident angle of about 60°. Figure 1 , Figure 1 The figure shows the relationship between the reflectivity and the incident angle of P-polarized light and S-polarized light when they are incident from air to glass, wherein the range marked by the dotted frame is the range of the incident angle of the light emitted by most head-up display systems. It can be seen that for most head-up display systems, after the light emitted by them reaches the windshield, part of the S-polarized light will be reflected on the surface of the glass, while the P-polarized light can almost completely pass through the glass. That is to say, if the projection light emitted by the head-up display system is S-polarized light, or more than 50% of the projection light is S-polarized light, since the structure of the windshield is composed of outer glass and inner glass, the S-polarized light will be reflected on both the inner glass surface and the outer glass surface at the same time, forming a double image.

[0033] Furthermore, the inventors have found that if the problem of double images on the windshield is to be eliminated, the light engine in the head-up display system can emit P polarized light or more than 50% of the projected light is P polarized light. Figure 2 , Figure 2 A schematic diagram showing a light beam emitted by a head-up display system incident on a windshield is shown. Figure 2 It can be seen that when the projection light (P polarized light) is incident from the inner surface of the windshield, most of the light can pass through the inner glass 1100 and enter the interior of the windshield. Furthermore, if a P polarized light reflection layer 1200 is set between the inner glass 1100 and the outer glass 1300 of the windshield, the P polarized light is reflected on the reflection layer 1200, which can greatly reduce the degree of ghosting.

[0034] See also Figure 3 , Figure 3The schematic diagram of the structure of a reflective film proposed in an embodiment of the present application is shown. Specifically, the reflective film 100 includes a low-refractive index medium layer 101 and a high-refractive index medium layer 102 stacked in sequence. Specifically, the low-refractive index medium layer refers to a medium layer with a refractive index in the range of 1 to 1.46, and the high-refractive index medium layer refers to a medium layer with a refractive index in the range of 2 to 2.5. Further, the low-refractive index medium layer 101 is a silicon dioxide film layer with a porous structure. As an embodiment, the size of the low-refractive index medium layer 101 is the same as that of the high-refractive index medium layer 102, and the low-refractive index medium layer 101 and the high-refractive index medium layer 102 are stacked in sequence to completely overlap.

[0035] Specifically, porosity refers to the proportion of the volume of pores in the membrane layer to the volume of the membrane layer. For example, a porosity of 50% means that the volume of pores in the membrane layer accounts for 50% of the volume of the membrane layer. In addition, the greater the porosity of the porous silica membrane layer, the lower the density of the membrane layer and the lower the refractive index of the membrane layer. Taking the extreme case as an example, if the porosity is 0, the refractive index of the membrane layer is the same as that of the silica dielectric layer, which is 1.46. If the porosity is 100%, it means that the membrane layer is all air. At this time, the refractive index of the membrane layer is equal to the refractive index of air, which is 1. Therefore, when the porosity of the porous silica membrane layer takes any value between 0-100%, its refractive index can change accordingly between 1.46 and 1. For further information, please refer to Figure 4 , Figure 4 A schematic diagram showing the relationship between the refractive index and porosity of a low-refractive-index medium layer in a reflective film proposed in an embodiment of the present application is shown. Figure 4 It can be seen that, for example, when the porosity of the dielectric layer is about 49%, the corresponding refractive index is about 1.2, and the refractive index of the low refractive index dielectric layer is inversely proportional to the porosity of the low refractive index dielectric layer. It should be understood that the specific relationship between the porosity and the refractive index of the low refractive index dielectric layer will present different results depending on the process conditions, materials, test conditions, etc. of the dielectric layer. Figure 4 The relationships shown are examples only.

[0036] As an implementation mode, the low refractive index medium layer 101 can be prepared by a physical method or a chemical method, for example, a physical method such as oblique coating, etching or ion implantation, or a chemical method such as sol-gel or template method, or a combination of physical and chemical methods, can be used to prepare a silicon dioxide film containing pores for use as the low refractive index medium layer 101. Furthermore, by controlling the porosity of the prepared silicon dioxide film, the refractive index of the low refractive index medium layer 101 can be gradually changed in the range of approximately 1 to 1.46, thereby achieving an ultra-low refractive index of the low refractive index medium layer 101.

[0037] As an implementation, the high refractive index medium layer 102 can be made of a material with a refractive index greater than 1.8, such as titanium dioxide (refractive index is about 2.32), tantalum pentoxide (refractive index is about 2.14) or niobium pentoxide (refractive index is about 2.32).

[0038] As an implementation method, niobium pentoxide Nb2O5 is selected to prepare the high refractive index medium layer 102, so that the refractive index of the high refractive index medium layer 102 is 2.32, and the refractive index of the low refractive index medium layer 101 is reduced to 1.2 by adjusting the porosity of the silicon dioxide film with a porous structure, thereby increasing the refractive index difference between the medium layers with different refractive indices in the reflective film layer. Since the greater the difference in optical density (refractive index) between the two media, the greater the energy carried away by the reflected wave at the interface, that is, the higher the reflectivity of the reflective film, under the same number of layers, the combination of materials with a large refractive index difference can obtain a higher reflectivity, that is, increasing the refractive index between the low refractive index medium layer and the high refractive index medium layer can make the required film system involved and prepared as simple as possible when achieving the desired reflectivity value.

[0039] As an implementation method, according to the needs of actual applications, other functional layers, such as a conductive layer, a heat insulating layer, a primer layer, an isolation layer, etc., may be added to the reflective film to achieve corresponding functions.

[0040] Therefore, when the reflective film is applied to the windshield, after the P polarized light emitted by the head-up display system reaches the windshield, the P polarized light will pass through the glass layer in the windshield and be reflected on the reflective film 100. Since the reflective film 100 provided in the embodiment of the present application is composed of a low refractive index medium layer and a high refractive index medium layer stacked in sequence, wherein the low refractive index medium layer is a porous structured silica film layer, and the refractive index of the porous structured silica film layer can gradually change within a range of approximately 1 to 1.46, the greater the refractive index difference between the multiple layers of medium constituting the reflective film layer, the easier it is to achieve the desired effect with a simpler film system structure, that is, it is easier to achieve the purpose of reflecting the P polarized light on the reflective film.

[0041] Therefore, by using a porous silicon dioxide film layer as a low-refractive index medium layer, the purpose of increasing the refractive index difference of each medium in the reflective film can be achieved by lowering the refractive index of the low-refractive index medium, so that the film system structure of the reflective film is simpler, and its thickness and preparation process are easier to control. The windshield using the reflective film has a better reflection effect on P-polarized light. Experimental verification shows that the P-polarized light reflection spectrum and the full light transmission spectrum are smooth, achieving a neutral color display of the head-up display image, thereby improving the image display effect of the head-up display system.

[0042] See also Figure 5 , Figure 5The schematic diagram of the structure of another reflective film proposed in the embodiment of the present application is shown. Specifically, the reflective film 200 includes a low refractive index medium layer 201 and a high refractive index medium layer 202 stacked in sequence. The reflective film 200 also includes a medium refractive index medium layer 203, which is stacked on the side of the high refractive index medium layer 202 away from the low refractive index medium layer 201, wherein the low refractive index medium layer 201 is a silicon dioxide film layer with a porous structure. As an embodiment, the size of the low refractive index medium layer 201 is the same as that of the medium refractive index medium layer 203 and the high refractive index medium layer 202, and the low refractive index medium layer 201, the high refractive index medium layer 202 and the medium refractive index medium layer 203 are stacked in sequence to completely overlap.

[0043] As an implementation mode, the low refractive index dielectric layer 201 has a refractive index of 1.2 and a thickness in the range of 60nm-75nm, the high refractive index dielectric layer 202 is a niobium pentoxide Nb2O5 layer with a refractive index of 2.32 and a thickness in the range of 60nm-85nm, and the medium refractive index dielectric layer 203 is an aluminum oxide Al2O3 layer with a refractive index of 1.67 and a thickness in the range of 90nm-110nm.

[0044] As an implementation method, according to the needs of actual applications, other functional layers, such as a conductive layer, a heat insulating layer, a primer layer, an isolation layer, etc., may be added to the reflective film to achieve corresponding functions.

[0045] In this embodiment, it has been verified through experiments that the reflective film proposed in this embodiment can achieve a reflectivity of about 20% for P-polarized light incident at 60 degrees and a transmittance of about 80% for natural light incident at 0 degrees. Therefore, when the reflective film is applied to the windshield, the projection light (here, it is assumed that the projection light is P-polarized light) emitted by the head-up display system is reflected on the reflective film after entering the windshield and reaches the human eye to form an image, while the ambient natural light around the vehicle can penetrate the windshield without affecting the driver's normal field of vision, thereby achieving a good head-up display effect. For details, please refer to Figure 6 , Figure 6 A curve diagram showing the reflectivity and transmittance of a light incident on the reflective film proposed in the embodiment of the present application is shown. Figure 6It can be seen that in the full band of 450nm-650nm, when P-polarized light enters the reflective film 200 at an incident angle of 60 degrees (i.e., the incident angle of most head-up display systems when the projection light enters the windshield), the reflectivity is between 19.5% and 21.1%; when natural light enters the reflective film 200 at an incident angle of 0 degrees, the transmittance is between 81% and 83%. That is to say, in the full band of 450nm-650nm, the extreme difference in the reflectivity of P-polarized light is less than or equal to 3%, and the full spectrum transmittance is 10%. The extreme difference of the reflectivity is less than or equal to 3%, that is, the difference between the maximum and minimum values ​​of the reflectivity or transmittance in the entire band of 450nm-650nm is less than or equal to 3%, and can even be less than or equal to 2%. Therefore, the reflective film 200 makes the incident P-polarized light reflection spectrum and the natural light transmission spectrum smooth. When it is applied to the windshield, it can achieve a neutral color display of the head-up display image, and make the overall haze less than 2% or even 1%, thereby ensuring the light transmittance of the windshield while improving the projection display effect.

[0046] See also Figure 7 , Figure 7 The schematic diagram of the structure of another reflective film proposed in the embodiment of the present application is shown. Specifically, the reflective film 300 includes a low refractive index medium layer 301 and a high refractive index medium layer 302 stacked in sequence. The reflective film 300 also includes a metal layer 303. The metal layer 303 is stacked and arranged on the side of the high refractive index medium layer 302 away from the low refractive index medium layer 301, wherein the low refractive index medium layer 301 is a silicon dioxide film layer with a porous structure. As an embodiment, the size of the low refractive index medium layer 301 is the same as that of the metal layer 303 and the high refractive index medium layer 302, and the low refractive index medium layer 301, the high refractive index medium layer 302 and the metal layer 303 are stacked in sequence to completely overlap.

[0047] As an implementation mode, the low refractive index dielectric layer 301 has a refractive index of 1.2 and a thickness in the range of 5nm-15nm, the high refractive index dielectric layer 302 is a niobium pentoxide Nb2O5 layer with a refractive index of 2.32 and a thickness in the range of 33nm-44nm, and the metal layer 303 is a silver Ag layer with a thickness in the range of 6nm-12nm. Adding a metal layer to the reflective film significantly reduces the thickness of each dielectric layer of the reflective film.

[0048] As an implementation method, according to the needs of actual applications, other functional layers, such as a conductive layer, a heat insulating layer, a primer layer, an isolation layer, etc., may be added to the reflective film to achieve corresponding functions.

[0049] In this embodiment, it has been verified through experiments that the reflective film proposed in this embodiment can achieve a reflectivity of about 19% for P-polarized light incident at 60 degrees and a transmittance of about 85% for natural light incident at 0 degrees. Therefore, when the reflective film is applied to the windshield, the projection light (here, it is assumed that the projection light is P-polarized light) emitted by the head-up display system is reflected on the reflective film after entering the windshield and reaches the human eye to form an image, while the ambient natural light around the vehicle can penetrate the windshield without affecting the driver's normal field of vision, thereby achieving a good head-up display effect. For details, please refer to Figure 8 , Figure 8 A curve diagram showing the reflectivity and transmittance of another light incident on the reflective film proposed in the embodiment of the present application is shown. Figure 8 It can be seen that in the full band of 450nm-650nm, when P-polarized light enters the reflective film 300 at an incident angle of 60 degrees (i.e., the incident angle of most head-up display systems when projecting light entering the windshield), the reflectivity is between 18% and 20%; when natural light enters the reflective film 300 at an incident angle of 0 degrees, the transmittance is between 84% and 86%. That is to say, in the full band of 450nm-650nm, the extreme difference in the reflectivity of P-polarized light is less than or equal to 3%, and the full spectrum transmittance is The extreme difference is less than or equal to 3%, that is, the difference between the maximum and minimum values ​​of the reflectivity or transmittance in the entire band of 450nm-650nm is less than or equal to 3%, and can even be less than or equal to 2%. Therefore, the reflective film 300 makes the incident P-polarized light reflection spectrum and the natural light transmission spectrum smooth. When it is applied to the windshield, it can achieve a neutral color display of the head-up display image, so that the overall haze is less than 2% or even 1%, thereby ensuring the light transmittance of the windshield while improving the projection display effect.

[0050] See also Fig. 9 , Fig. 9 A schematic diagram of the structure of another reflective film proposed in an embodiment of the present application is shown. Specifically, the reflective film 400 includes a plurality of low-refractive index medium layers and high-refractive index medium layers alternately stacked in sequence, wherein the low-refractive index medium layers are all silicon dioxide film layers with a porous structure. Exemplarily, the reflective film 400 includes a first high-refractive index medium layer 401, a first low-refractive index medium layer 402, a second high-refractive index medium layer 403, a second low-refractive index medium layer 404, a third high-refractive index medium layer 405 and a third low-refractive index medium layer 406, wherein the first low-refractive index medium layer 402, the second low-refractive index medium layer 404 and the third low-refractive index medium layer 406 are all silicon dioxide film layers with a porous structure. As an embodiment, the size of each low-refractive index medium layer is the same as the size of the high-refractive index medium layer, and the sequential stacking between each low-refractive index medium layer and the high-refractive index medium layer is in a completely overlapping state.

[0051] As an implementation manner, the refractive index of the first low refractive index medium layer 402, the second low refractive index medium layer 404 and the third low refractive index medium layer 406 is 1.2, the thickness of the first low refractive index medium layer 402 is in the range of 35nm-41nm, the thickness of the second low refractive index medium layer 404 is in the range of 12nm-18nm, and the thickness of the third low refractive index medium layer 406 is in the range of 102nm-106nm; the first high refractive index medium layer 401, the second high refractive index medium layer 403 and the third high refractive index medium layer 405 are all niobium pentoxide Nb2O5 layers, and the refractive index is 2.32, the thickness of the first high refractive index medium layer 401 is in the range of 9nm-15nm, the thickness of the second high refractive index medium layer 403 is in the range of 30nm-36nm, and the thickness of the third high refractive index medium layer 405 is in the range of 31nm-37nm. It should be noted that in practical applications, since each low-refractive index medium layer is a porous structure, it is necessary to avoid the influence of the holes in the low-refractive index medium layer, especially the open holes, on other film layers covering it during preparation. If there is any influence, the film system structure can be re-optimized according to the actual refractive index requirements.

[0052] As an implementation method, according to the needs of actual applications, other functional layers, such as a conductive layer, a heat insulating layer, a primer layer, an isolation layer, etc., may be added to the reflective film to achieve corresponding functions.

[0053] In this embodiment, it has been verified through experiments that the reflective film proposed in this embodiment can achieve a reflectivity of about 20% for P-polarized light incident at 60 degrees and a transmittance of about 81% for natural light incident at 0 degrees under ideal conditions. Therefore, when the reflective film is applied to the windshield, the projection light (here, it is assumed that the projection light is P-polarized light) emitted by the head-up display system is reflected on the reflective film after entering the windshield and reaches the human eye to form an image, while the ambient natural light around the vehicle can penetrate the windshield without affecting the driver's normal field of vision, thereby achieving a good head-up display effect. For details, please refer to Fig.10 , Fig.10 A curve diagram showing the reflectivity and transmittance of another light incident on the reflective film proposed in the embodiment of the present application is shown. Fig.10It can be seen that in the full band of 450nm-650nm, when P-polarized light enters the reflective film 400 at an incident angle of 60 degrees (i.e., the incident angle of most head-up display systems when the projection light enters the windshield), the reflectivity is between 19.4% and 21.2%; when natural light enters the reflective film 400 at an incident angle of 0 degrees, the transmittance is between 80% and 82%. That is to say, in the full band of 450nm-650nm, the extreme difference in the reflectivity of P-polarized light is less than or equal to 3%, and the full spectrum transmittance is 1.5%. The extreme difference of the reflectivity is less than or equal to 3%, that is, the difference between the maximum and minimum values ​​of the reflectivity or transmittance in the entire band of 450nm-650nm is less than or equal to 3%, and can even be less than or equal to 2%. Therefore, the reflective film 400 makes the incident P-polarized light reflection spectrum and the natural light transmission spectrum smooth. When it is applied to the windshield, it can achieve a neutral color display of the head-up display image, so that the overall haze is less than 2% or even 1%, thereby ensuring the transmittance of the windshield while improving the projection display effect.

[0054] See also Fig.11 , Fig.11 The windshield 500 includes an inner glass 501, an outer glass 503 and a reflective film 502 as described in any of the above embodiments. Fig.11 In the example, the reflective film 502 includes a stacked low refractive index medium layer 504 and a high refractive index medium layer 505. Further, the inner glass 501 is arranged on a side of the reflective film 502 close to the low refractive index medium layer 504, and the outer glass 503 is arranged on a side of the reflective film 502 close to the high refractive index medium layer 505.

[0055] According to the above analysis, in the head-up display system, light is irradiated onto the windshield at a specific incident angle and is reflected. Generally, the incident angle range of the light emitted by the optical machine is 50°-70°, and the light usually irradiates the windshield at an incident angle of about 60°, and the P-polarized light incident at this angle can almost completely pass through the glass. When the projection light emitted by the head-up display system is P-polarized light, the projection light can completely pass through the inner glass 501 to reach the reflective film 502 and then be reflected by the reflective film 502 to the driver's eyes to form an image, while the ambient natural light around the vehicle passes through the outer glass 503 to reach the reflective film 502 and then is transmitted by the reflective film 502 to the interior of the vehicle. Therefore, the windshield provided in the embodiment of the present application can achieve a good head-up display effect while ensuring the driver's normal field of vision.

[0056] As an implementation, see Fig.12 , Fig.12 FIG. 2 shows a schematic diagram of the structure of another windshield proposed in an embodiment of the present application. For example, Fig.12As shown in FIG. 1 , the windshield includes an inner glass 601, an outer glass 602, a reflective film 603 and a bonding layer 604 as described in any of the above embodiments. Further, the reflective film 603 can be directly disposed on the inner surface of the outer glass 602 by vacuum coating, and then bonded to the inner glass 601 by the bonding layer 604. For example, Fig.12 As shown in FIG. 2 , the windshield includes an inner glass 701, an outer glass 702, a reflective film 703 and a bonding layer 704 as described in any of the above embodiments. Further, the reflective film 703 can be directly disposed on the inner surface of the inner glass 701 by vacuum coating, and then bonded to the outer glass 702 by the bonding layer 704. For example, Fig.12 As shown in FIG. 3 , the windshield includes an inner glass 801, an outer glass 802, a reflective film 803 and a bonding layer 804 as described in any of the above embodiments. Further, the reflective film 803 is bonded to the inner glass 801 and the outer glass 802 respectively through the bonding layer 804. For example, Fig.12 d, the windshield includes an inner glass 901, an outer glass 902, a reflective film 903 described in any of the above embodiments, a bonding layer 904 and a functional layer 905, wherein the reflective film can be bonded to the inner glass and the outer glass respectively through the bonding layer, or can be directly disposed on the inner surface of the outer glass through vacuum coating, and then bonded to the inner glass through the bonding layer, or can be directly disposed on the inner surface of the outer glass through vacuum coating, and then bonded to the inner glass through the bonding layer, Fig.12 The method shown in d is that the reflective film 903 is respectively bonded to the inner glass 901 and the outer glass 902 through the bonding layer 904, and the functional layer 905 may include but is not limited to a transparent substrate, an ultraviolet protection layer, a conductive layer, an anti-riot layer and other dielectric layers arranged based on actual needs, and the functional layer may be a single layer or a superposition of multiple layers of any of the above dielectric layers, which will not be repeated here. Furthermore, the functional layer 905 is stacked between the outer glass 902 and the reflective film 903.

[0057] According to the above analysis, the windshield provided in the embodiment of the present application has a simple film structure and a lower film thickness of the reflective film, which facilitates the addition of a bonding layer and other functional layers to the windshield, and the haze of the film layer is lower, thereby achieving a good head-up display effect while ensuring the driver's normal field of vision.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A reflective film, characterized in that: include: A low-refractive-index medium layer and a high-refractive-index medium layer stacked in sequence; Among them, the low refractive index medium layer is a silicon dioxide film layer with a porous structure, and the refractive index of the low refractive index medium layer is inversely proportional to the porosity of the low refractive index medium layer. The porosity refers to the proportion of the volume of pores in the film layer to the volume of the film layer.

2. The reflective film according to claim 1, characterized in that The refractive index of the low-refractive-index medium layer is 1.

2.

3. The reflective film according to claim 1, characterized in that The refractive index of the high refractive index medium layer is 2.

32.

4. The reflective film according to claim 1, characterized in that The reflective film further comprises a medium refractive index medium layer, and the medium refractive index medium layer is stacked and arranged on a side of the high refractive index medium layer away from the low refractive index medium layer.

5. The reflective film according to claim 4, characterized in that The refractive index of the medium refractive index medium layer is 1.

67.

6. The reflective film according to claim 1, characterized in that The reflective film further comprises a metal layer, and the metal layer is stacked and arranged on a side of the high refractive index medium layer away from the low refractive index medium layer.

7. The reflective film according to claim 1, characterized in that The reflective film includes a plurality of low-refractive index medium layers and a plurality of high-refractive index medium layers, and each of the low-refractive index medium layers and each of the high-refractive index medium layers are alternately stacked in sequence.

8. A windshield, characterized in that: include: The inner glass, the outer glass and the reflective film as described in any one of claims 1 to 7 are stacked, wherein the inner glass is arranged on the side of the reflective film close to the low refractive index medium layer, and the outer glass is arranged on the side of the reflective film close to the high refractive index medium layer.

9. The windshield according to claim 8, characterized in that: The windshield further comprises a bonding layer, and the reflective film is laminated with the inner glass or the outer glass via the bonding layer.

10. The windshield according to claim 8, characterized in that: The windshield further includes a functional layer, which is stacked between the outer glass and the reflective film.

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