Vehicle window glass, head-up display device, vehicle, and exposure optical path system

Abstract

A piece of vehicle window glass (22), a head-up display device (20), a vehicle (100), and an exposure optical path system (300). The vehicle window glass (22) comprises a glass substrate (221), a holographic film material (222) and a first protective film (223). The glass substrate (221) comprises an outer glass pane (2211), an inner glass pane (2212) and an intermediate layer, wherein the outer glass pane (2211) and the inner glass pane (2212) are stacked, and the intermediate layer is connected between the outer glass pane (2211) and the inner glass pane (2212). The holographic film material (222) is located between the outer glass pane (2211) and the intermediate layer; alternatively, the holographic film material (222) is located between the intermediate layer and the inner glass pane (2212). The holographic film material (222) comprises a first region (2221) and a second region (2222). The first region (2221) is provided with a first grating (2223), and the second region (2222) is provided with a second grating (2224). The included angle (α1) between the first grating (2223) and a surface of the holographic film material (222) is different from the included angle (α2) between the second grating (2224) and the surface of the holographic film material (222).

Description

Vehicle windows, head-up displays, vehicles and their exposure optical systems

[0001] This application claims priority to Chinese Patent Application No. 202411470837.2, filed on October 21, 2024, with the China National Intellectual Property Administration, entitled “Vehicle Window Glass, Head-Up Display Device, Vehicle and Exposure Optical Path System Thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of glass technology, and more particularly to a vehicle window glass, a head-up display device, a vehicle, and an exposure optical path system. Background Technology

[0003] Currently, vehicle head-up display systems display the vehicle's instrument panel information and navigation direction information on the same focal plane. This can cause the instrument panel information to overlap with the foreground when the vehicle is driving on urban roads, thus interfering with the driver's vision. Summary of the Invention

[0004] The embodiments of this application provide a vehicle window glass, a head-up display device, a vehicle, and an exposure optical path system, which can display different vehicle projection information on different focal planes, thereby improving the safety of the driver.

[0005] In a first aspect, this application provides a vehicle window glass, including a glass substrate and a holographic film material. The glass substrate includes an outer glass plate, an inner glass plate and an intermediate layer. The outer glass plate and the inner glass plate are stacked, and the intermediate layer is connected between the outer glass plate and the inner glass plate.

[0006] The holographic film is located between the outer glass plate and the intermediate layer, or the holographic film is located between the intermediate layer and the inner glass plate. The holographic film includes a first region and a second region. The first region has a first grating, and the second region has a second grating. The angle between the first grating and the surface of the holographic film is different from the angle between the second grating and the surface of the holographic film.

[0007] In this embodiment, the driver does not need to look down at the instrument panel or central control screen; their gaze can remain fixed on the road ahead, thus reducing potential hazards caused by distraction. This feature is particularly important during high-speed or nighttime driving, as it helps the driver react more quickly and avoid potential accidents. The driver does not need to frequently adjust their eye focus to check projected information and road conditions separately, reducing eye fatigue. Over time, this helps maintain the driver's attention and alertness, improving driving safety.

[0008] In one possible implementation, the window glass further includes a first protective film located between the intermediate layer and the holographic film.

[0009] In one possible implementation, the window glass further includes a second protective film attached to the surface of the holographic film material opposite to the first protective film.

[0010] In one possible implementation, there are two intermediate layers: one intermediate layer is connected to the surface of the first protective film facing away from the holographic film, and the other intermediate layer is connected to the surface of the second protective film facing away from the holographic film.

[0011] In one possible implementation, both the first grating and the second grating include periodic stripes, wherein the angle between the periodic stripes of the first grating and the surface of the holographic film is within one of the ranges of 0–35°, 42–55°, and 60–85°, and the angle between the periodic stripes of the second grating and the surface of the holographic film is within another of the ranges of 0–35°, 42–55°, and 60–85°.

[0012] In one possible implementation, the stripe spacing of the periodic stripes of the first grating is in the range of 200 nm to 400 nm.

[0013] In one possible implementation, the thickness of the holographic film is in the range of 15μm-120μm.

[0014] Secondly, this application also provides a head-up display device, including an image generating unit and a vehicle window glass as described above. The image generating unit is used to project light onto a first region and a second region of the holographic film. The first region and the second region reflect the projected light, so that the images corresponding to the first region and the second region are focused at different depths of the holographic film.

[0015] Thirdly, this application also provides a vehicle, including a vehicle body and a head-up display device as described above, the head-up display device being connected to the vehicle body.

[0016] Fourthly, this application provides an exposure optical path system for holographic films, used to prepare holographic films. The exposure optical path system includes a first laser, a first beam splitting unit, a first light intensity control unit, a second light intensity control unit, a first angle control unit, a second angle control unit, and a moving unit.

[0017] The first laser is used to emit the first laser beam.

[0018] The first beam splitting unit is used to receive the first laser beam and split the first laser beam into a first sub-beam and a second sub-beam.

[0019] The first light intensity control unit is used to receive the first sub-beam and adjust the light intensity of the first sub-beam to form a first recording light.

[0020] The first angle control unit is used to receive the first recording light and adjust the angle of the first recording light so that the first recording light illuminates a first area of ​​the substrate.

[0021] The second light intensity control unit is used to receive the second sub-beam and adjust the light intensity of the second sub-beam to form a second recording light.

[0022] The second angle control unit is used to receive the second recording light and adjust the angle of the second recording light so that the second recording light illuminates the first area of ​​the substrate.

[0023] The second recording light and the first recording light are respectively used to irradiate opposite sides of the substrate in the thickness direction, so that the first region forms the first grating of the holographic film material.

[0024] The moving unit is used to connect to the substrate and move the substrate so that the first recording light and the second recording light irradiate a second area of ​​the substrate, so that the second area forms a second grating of holographic film.

[0025] In this embodiment, the exposure optical path system avoids using a large refractive mirror. Instead, it uses a light intensity control unit and an angle control unit to adjust the intensity and angle of the first and second recording lights, allowing them to directly illuminate opposite sides of the substrate in the thickness direction. The first and second recording lights meet and interfere within the substrate. In areas of enhanced interference, the light intensity is increased, resulting in a higher light intensity on the film. In areas of weakened interference, the light intensity is decreased, resulting in a lower light intensity on the film. Since the substrate's absorption, reflection, or refraction of light may change depending on the light intensity, specific patterns or structures will form on the substrate in areas of enhanced and weakened interference. These patterns or structures are the basic units of the grating: slits or grooves.

[0026] It is known that currently, convex lenses and other transmissive mirrors are generally used to form coherent light on the substrate, thereby forming a grating on the substrate. However, due to the shape limitations of convex lenses, if multiple gratings need to be fabricated on the same substrate, multiple lenses need to be used during the substrate processing. This results in a longer production process, increases the possibility of production defects in the holographic film material, and consequently affects the production yield of the holographic film material, increasing the production cost of the head-up display device.

[0027] Because the exposure optical path system has a light intensity control unit, an angle control unit, and a movement unit, it can theoretically illuminate any area of ​​the substrate within an adjustable range at any angle within the adjustable range with light of any intensity within the adjustable range. The exposure optical path system of this application can directly change the angle, intensity, and incident position of the coherent light without replacing the lens. The substrate can form the first and second gratings in the same process, thereby simplifying the holographic film material preparation process, reducing the possibility of production defects in the holographic film material, improving the production yield of the holographic film material, and saving production costs for head-up display devices and vehicles.

[0028] In one possible implementation, the exposure optical path system further includes a second laser for emitting a second laser of a different color than the first laser.

[0029] The exposure optical path system further includes a second beam splitting unit, which is used to receive the second laser and split the second laser into a third sub-beam and a fourth sub-beam.

[0030] The first light intensity control unit is used to receive the first sub-beam and the third sub-beam, and adjust the light intensity of the first sub-beam and the third sub-beam to form a third recording light. The second light intensity control unit is used to receive the second sub-beam and the fourth sub-beam, and adjust the light intensity of the second sub-beam and the fourth sub-beam to form a fourth recording light.

[0031] In one possible implementation, the exposure optical path system further includes a third laser for emitting a third laser, wherein the first laser, the second laser, and the third laser are of different colors.

[0032] The exposure optical path system also includes a third beam splitting unit, which is used to receive the third laser and split the third laser into a fifth sub-beam and a sixth sub-beam.

[0033] The first light intensity control unit is used to receive the first sub-beam, the third sub-beam, and the fifth sub-beam, and adjust the light intensity of the first sub-beam, the third sub-beam, and the fifth sub-beam to form a third recording light. The second light intensity control unit is used to receive the second sub-beam, the fourth sub-beam, and the sixth sub-beam, and adjust the light intensity of the second sub-beam, the fourth sub-beam, and the sixth sub-beam to form a fourth recording light.

[0034] In this embodiment, by adjusting the intensity ratio and angle parameters of the incident beam in the exposure system, grating fringes with different periods and tilt angles are formed inside the holographic material, resulting in holographic films with different focal planes. These films can reflect and image light of multiple wavelengths, and can reflect and image off-axis or on the same optical axis while exhibiting near-total transmission of other wavelengths. They possess the characteristic of almost total reflection of selected wavelengths and total transmission of non-selected wavelengths. This allows the holographic film to reflect projected light to form an image while directly transmitting other rays of sunlight without affecting image clarity.

[0035] In one possible implementation, the first laser is red light, the second laser is green light, and the third laser is blue light. The intensity ratio of the red light to the green light is between 1 and 1.5, and the intensity ratio of the blue light to the green light is between 1.5 and 2.

[0036] In this embodiment, by adjusting the intensity ratio of red, green, and blue light, the spectral bandwidth of the grating formed by the interference of the third and fourth recording lights is increased, thereby enabling the first and second gratings to reflect light of wavelengths within the visible light range, thus enriching the colors of the images in the first and second regions.

[0037] In one possible implementation, the exposure optical path system further includes a first reflector, which is used to reflect the first recording light emitted by the first light intensity control unit toward the first angle control unit.

[0038] In this embodiment, the first reflector can flexibly adjust the direction of light path propagation from the first light intensity control unit to the first angle control unit, so that the relative positions of the first light intensity control unit and the first angle control unit can be flexibly set.

[0039] In one possible implementation, the exposure optical path system further includes a first reflector, a second reflector, and a third reflector;

[0040] The third recording light includes red light, green light, and blue light. The first reflector is used to reflect the red light, the second reflector is used to reflect the green light, and the third reflector is used to reflect the blue light, so that the red light, the green light, and the blue light are mixed to form white light, which is then reflected to the first angle control unit.

[0041] In one possible implementation, the first angle control unit and the second angle control unit are located on opposite sides of the moving unit.

[0042] In this embodiment, the moving unit can control the substrate to move between the first angle control unit and the second angle control unit, so that the first recording light and the second recording light can interfere at any position on the substrate to form a grating.

[0043] In one possible implementation, the second light intensity control unit is located on the laser propagation path of the first laser.

[0044] In this embodiment, the first beam splitting unit can reflect part of the first laser beam to the first light intensity control unit, while the other part of the first laser beam can directly irradiate the second light intensity control unit. Attached Figure Description

[0045] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 is a structural schematic diagram of the vehicle provided in an embodiment of this application;

[0047] Figure 2 is a schematic diagram of one structure of the head-up display device shown in Figure 1;

[0048] Figure 3 is a cross-sectional schematic diagram of the car window glass shown in Figure 2;

[0049] Figure 4 is a structural schematic diagram of the car window glass shown in Figure 2 from another angle;

[0050] Figure 5 is a schematic diagram of another structure of the head-up display device shown in Figure 1;

[0051] Figure 6 is another cross-sectional view of the car window glass shown in Figure 2;

[0052] Figure 7 is another cross-sectional view of the car window glass shown in Figure 2;

[0053] Figure 8 is another cross-sectional view of the car window glass shown in Figure 2;

[0054] Figure 9 is a schematic diagram illustrating the principle of holographic film formation by exposure interference;

[0055] Figure 10 is a schematic diagram of an exposure optical path system provided in an embodiment of this application;

[0056] Figure 11 is a schematic diagram of another exposure optical path system provided in an embodiment of this application.

[0057] Reference numerals: Vehicle 100, Vehicle body 10, Head-up display device 20, Image generation unit 21, Window glass 22, Glass substrate 221, Holographic film 222, Outer glass plate 2211, Inner glass plate 2212, First intermediate layer 2213, Second intermediate layer 2214, First region 2221, Second region 2222, First grating 2223, Second grating 2224, Third region 2225, First protective film 223, Second protective film 224, Exposure optical path system 300, First recording light 301, Second recording light 302, Third recording light 303, Fourth recording light 304, First laser 310, First beam splitting unit 320, First light intensity control unit 330, Second light intensity control unit 3 40. First angle control unit 350, second angle control unit 360, moving unit 370, first laser 311, first sub-beam 3111, second sub-beam 3112, substrate 2220, first reflector 380, second reflector 381, third reflector 382, ​​fourth reflector 383, fifth reflector 384, second laser 390, third laser 400, second beam splitting unit 410, third beam splitting unit 420, second laser 391, third laser 401, third sub-beam 3911, fourth sub-beam 3912, fifth sub-beam 4011, sixth sub-beam 4012, sixth reflector 385, seventh reflector 386, eighth reflector 387, ninth reflector 388. Detailed Implementation

[0058] For ease of understanding, the terminology used in the embodiments of this application will be explained first.

[0059] And / or: This is simply a way of describing the relationship between related objects. It indicates that there can be three kinds of relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0060] Multiple: refers to two or more.

[0061] Connection: should be interpreted broadly. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through an intermediary.

[0062] The specific embodiments of this application will now be clearly described in conjunction with the accompanying drawings.

[0063] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 100 provided in an embodiment of this application. The vehicle 100 includes a vehicle body 10 and a head-up display device 20. The head-up display device 20 is connected to the vehicle body 10.

[0064] It should be noted that Figure 1 is only intended to schematically illustrate the connection relationship between the vehicle body 10 and the head-up display device 20, and is not intended to specifically limit the connection position, specific structure, or quantity of each device. Furthermore, the structure illustrated in the embodiments of this application does not constitute a specific limitation on the vehicle 100. In other embodiments of this application, the vehicle 100 includes more or fewer components than shown in Figure 1, or combines or separates certain components, or has different component arrangements.

[0065] Please refer to Figure 2, which is a schematic diagram of one structure of the head-up display device 20 shown in Figure 1. The head-up display device 20 includes an image generation unit 21 (PGU) and a window glass 22. The image generation unit 21 projects light onto the window glass 22. The image generation unit 21 forms an image based on the projected light. The wavelength of the projected light can be in the range of 380nm to 780nm, which is close to the spectral range of visible light perceptible to the human eye. The wavelength range of the projected light also covers the RGB wavelengths: 469nm (blue), 529nm (green), and 629nm (red). Therefore, the window glass 22 described in this application can cooperate with the image generation unit 21 to achieve full-color display of the head-up display image.

[0066] The image generating unit 21 can project light, including relevant text and image information such as speed, engine speed, fuel consumption, tire pressure, dynamic navigation, night vision, and real-view maps, onto the vehicle window 22. This allows an observer inside the vehicle to view the head-up display image located in front of the window 22, enabling the vehicle 100 to achieve a head-up display (HUD), or even an augmented reality head-up display (AR-HUD). The image generating unit 21 can be any component known to those skilled in the art, including but not limited to lasers, light-emitting diodes (LEDs), liquid crystal displays (LCDs), digital light processing (DLP), electroluminescent diodes (ELs), cathode ray tubes (CRTs), and vacuum fluorescent tubes (VFDs). Furthermore, the position and incident angle of the image generating unit 21 are adjustable to suit observers at different positions or heights within the vehicle.

[0067] Please refer to Figure 3, which is a cross-sectional schematic diagram of the vehicle window glass 22 shown in Figure 2. The vehicle window glass 22 includes a glass substrate 221 and a holographic film 222.

[0068] The glass substrate 221 can be laminated glass. The glass substrate 221 may include an outer glass plate 2211, an inner glass plate 2212, and an intermediate layer (not shown) disposed between the outer glass plate 2211 and the inner glass plate 2212. The transmittance of the outer glass plate 2211 and / or the inner glass plate 2212 for near-infrared light with wavelengths from 850 nm to 1650 nm can be greater than or equal to 91%, and the transmittance of the glass substrate 221 for visible light is greater than or equal to 70%, meeting the regulatory requirements for the windshield of vehicle 100.

[0069] It should be noted that the laminated glass used as a windshield is usually curved, but the shape of the laminated glass is not limited to the shape described above. It can be any shape that meets the requirements for use as a car window glass. For example, the glass substrate 221 can also be in the shape of a flat plate. The embodiments of this application do not have strict requirements on the shape of the glass substrate 221.

[0070] The outer glass panel 2211 and the inner glass panel 2212 can be ultra-clear glass (ultra-white glass). The ultra-clear glass has a low iron oxide (FeO) content. By weight percentage, the outer glass panel 2211 and the inner glass panel 2212 can contain 0 to 0.1% iron oxide (Fe2O3), for example, the iron oxide (Fe2O3) content in the outer glass panel 2211 and the inner glass panel 2212 is less than or equal to 0.09%, less than or equal to 0.08%, less than or equal to 0.07%, less than or equal to 0.05%, less than or equal to 0.04%, less than or equal to 0.03%, less than or equal to 0.02%, less than or equal to 0.015%, or less than or equal to 0.01%, or even essentially free of iron oxide (FeO). For example, the outer glass panel 2211 and the inner glass panel 2212 can be sodium-calcium silicate ultra-transparent glass, borosilicate glass, or high-alumina glass, etc. The outer glass panel 2211 can be a single pane of glass, double-layered glass, or insulated glass, etc. The inner glass panel 2212 can be a single pane of glass, double-layered glass, or insulated glass, etc. The thickness of the inner glass panel 2212 can be 2.1 mm, 2.0 mm, or 1.8 mm, etc., or the thickness of the inner glass panel 2212 can be less than or equal to 1.6 mm.

[0071] The interlayer connects the outer glass panel 2211 and the inner glass panel 2212, giving the window a laminated structure to improve safety and meet the safety standards and regulations for vehicle windows. The interlayer can be made of materials such as polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), thermoplastic polyurethane elastomer (TPU), or ionomer polymer film (SGP). For example, the interlayer can be a single-layer or multi-layer structure; multi-layer structures include, for example, double-layer, triple-layer, quadruple-layer, and five-layer structures.

[0072] For ease of description, the following illustration uses a two-layer intermediate layer. The two intermediate layers are a first intermediate layer 2213 and a second intermediate layer 2214. The outer glass plate 2211, the first intermediate layer 2213, the second intermediate layer 2214, and the inner glass plate 2212 are stacked sequentially. The materials of the first intermediate layer 2213 and the second intermediate layer 2214 can be PVB or EVA. The thickness of the first intermediate layer 2213 and the thickness of the second intermediate layer 2214 can be 0.76mm ± 0.02mm, or 0.38mm ± 0.02mm, or 200um~380um, or 100um~200um, or 50um~100um, or 50um. The adhesion strength of the first intermediate layer 2213 and the second intermediate layer 2214 is greater than or equal to 10MPa.

[0073] Please refer to Figures 2 and 4. Figure 4 is a structural schematic diagram of the vehicle window glass 22 shown in Figure 2 from another angle. The holographic film 222 has a first region 2221 and a second region 2222. The first region 2221 and the second region 2222 can be arranged alternately, or the first region 2221 and the second region 2222 can be arranged adjacent to each other. The first region 2221 has a first grating 2223. The first grating 2223 is located inside the holographic film 222. The second region 2222 has a second grating 2224. The included angle α1 between the first grating 2223 and the surface of the holographic film 222 is different from the included angle α2 between the second grating 2224 and the surface of the holographic film 222. The first grating 2223 and the second grating 2224 are formed by exposure interference of a portion of the structure of the holographic film 222. The imaging focal lengths of the first grating 2223 and the second grating 2224 are different.

[0074] In some other embodiments, please refer to FIG5, which is a schematic diagram of another structure of the head-up display device 20 shown in FIG1. ​​The holographic film 222 may also have a third region 2225. The third region 2225 may be spaced apart from the first region 2221 and the second region 2222. Alternatively, the third region 2225 may be located on the side of the second region 2222 facing away from the first region 2221. The third region 2225 has a third grating (not shown). The third grating is formed by exposure interference of a portion of the structure of the holographic film 222. The focal length of the third grating is different from that of the first grating 2223 and the second grating 2224.

[0075] In other embodiments, the holographic film 222 may include four or more regions, each region having a grating structure. Furthermore, the imaging focal length of the grating structure in each region is different. This application will now illustrate this with an example of the holographic film 222 having two regions.

[0076] In a first possible embodiment, please refer to Figure 6, which is another cross-sectional schematic diagram of the vehicle window glass 22 shown in Figure 2. A holographic film 222 is connected between the first intermediate layer 2213 and the second intermediate layer 2214. A first protective film 223 may be provided between the holographic film 222 and the first intermediate layer 2213. A second protective film 224 may be provided between the holographic film 222 and the second intermediate layer 2214. Exemplarily, the first protective film 223 and the second protective film 224 can be transparent films, and the materials of the first protective film 223 and the second protective film 224 can be PET, PC, TAC, PMMA, etc., and the light transmittance of the first protective film 223 and the second protective film 224 can be greater than or equal to 90%. Further, the light transmittance of the first protective film 223 and the second protective film 224 can be greater than or equal to 95%. The haze of the first protective film 223 and the second protective film 224 can be less than or equal to 1%. Furthermore, the haze of the first protective film 223 and the second protective film 224 can be less than or equal to 0.5%.

[0077] In this embodiment, the first protective film 223 and the second protective film 224 can prevent the holographic film 222 from being contaminated by the first intermediate layer 2213 and / or the second intermediate layer 2214, thereby preventing the grating structure on the holographic film 222 from being deformed due to the influence of the composition.

[0078] In a second possible embodiment, please refer to FIG7, which is another cross-sectional schematic diagram of the vehicle window glass 22 shown in FIG2. The glass substrate 221 may have an intermediate layer (first intermediate layer 2213). The holographic film 222 may be disposed between the first intermediate layer 2213 and the inner glass plate 2212, or the holographic film 222 may be disposed between the first intermediate layer 2213 and the outer glass plate 2211. A first protective film 223 may be provided between the holographic film 222 and the first intermediate layer 2213. For example, please refer to FIG8, which is yet another cross-sectional schematic diagram of the vehicle window glass 22 shown in FIG2. A second protective film 224 may be provided between the holographic film 222 and the inner glass plate 2212.

[0079] In this embodiment, the holographic film 222 can be placed on a glass plate (inner glass plate 2212 or outer glass plate 2211), and then superimposed with the first protective film 223, the first intermediate layer 2213 and another glass plate (outer glass plate 2211 or inner glass plate 2212) to form the car window glass 22.

[0080] In a third possible embodiment, the holographic film 222 can be attached to the side of the inner glass plate 2212 away from the intermediate layer.

[0081] In this embodiment, the glass substrate 221 can be formed in the existing manufacturing process, and the holographic film 222 can be added to the side of the glass substrate 221 facing the vehicle interior.

[0082] Please refer to Figure 2 again. The image generating unit 21 is used to project light onto the first region 2221 and the second region 2222 of the holographic film material 222. The first region 2221 and the second region 2222 reflect the projected light, so that the images corresponding to the first region 2221 and the second region 2222 are focused at different depths of the holographic film material 222.

[0083] Understandably, current head-up display (HUD) systems typically use geometric optical surface reflection imaging systems. To ensure a large image area, these systems require large freeform mirrors and other optical components to be combined in a specific way, resulting in a relatively bulky HUD system. This necessitates significant modifications to the vehicle's center console, raising substantial cost and safety concerns, which greatly hinders the widespread adoption of in-vehicle HUD systems.

[0084] Head-up display (HUD) systems primarily achieve imaging through projection, most commonly by directly using the reflection from the windshield. For HUD images, higher windshield reflectivity is better; however, for safety reasons, reflectivity cannot be too high. To achieve the desired imaging effect, a high-power image source is needed to increase the brightness of the image.

[0085] Furthermore, most current in-vehicle head-up display systems are single-focal-plane systems, where the vehicle's instrument panel information (such as speed and gear) and navigation direction information are displayed on the same focal plane. This can cause the instrument panel information to overlap with the foreground when driving on urban roads, thus interfering with the driver's vision.

[0086] Please refer to Figure 9. Figure 9 is a schematic diagram illustrating the principle of forming a holographic film 222 through exposure interference. In this embodiment, a holographic film 222 can be formed through exposure interference, and a periodic grating structure can be formed on the holographic film 222 through dual-beam interference.

[0087] Here, the coherent light illuminating the two surfaces of the holographic film 222 is defined as the first recording light 301 and the second recording light 302. The angle between the first recording light 301 and the normal to the surface of the holographic film 222 is θ1, and the angle between the second recording light 302 and the normal to the surface of the holographic film 222 is θ2. The angle between the first recording light 301 and the second recording light 302 is 2θ. The period of the grating of the holographic film 222 is Λ, and the wavelengths of the first recording light 301 and the second recording light 302 are λ. The refractive index of the holographic film 222 is n. The above parameters satisfy the following relationship: Λ=λ / (2n·sinθ).

[0088] In this application, the grating period and the tilt angle between the grating and the surface of the holographic film 222 are changed by adjusting the parameters of the first recording light 301 and the second recording light 302 in the exposure optical path system, thereby creating a holographic film 222 with a volume holographic grating having different focal planes. Here, the focal plane is not an actual existing plane; it refers to the projection position of the information seen by the driver. The focal plane can be the location of the virtual image of the projected image seen by the driver.

[0089] In one possible embodiment, please refer to FIG10, which is a schematic diagram of an exposure optical path system 300 provided in an embodiment of this application. The exposure optical path system 300 includes a first laser 310, a first beam splitting unit 320, a first light intensity control unit 330, a second light intensity control unit 340, a first angle control unit 350, a second angle control unit 360, and a moving unit 370.

[0090] The first laser 310 is used to emit the first laser 311. The first laser 310 can be a laser source with a coherence length greater than or equal to 50 m. The first laser 310 can be a helium-cadmium laser, a single-mode laser, or an argon-ion laser, etc. The color of the first laser 311 can be white light or a single color light, etc. The color of the first laser 311 can be adjusted according to the preparation requirements of the holographic film 222. This application does not limit the laser color or type of the first laser 311.

[0091] The first beam splitting unit 320 is used to receive the first laser 311 and split the first laser 311 into a first sub-beam 3111 and a second sub-beam 3112.

[0092] The first light intensity control unit 330 is used to receive the first sub-beam 3111 and adjust the light intensity of the first sub-beam 3111 to form the first recording light 301. Specifically, by adjusting the intensity ratio of different wavelengths of the first recording light 301, the spectral bandwidth of the grating of the volume holographic film 222 is increased. For example, the first light intensity control unit 330 typically uses a waveplate combined with a polarizer and an adjustable attenuator to achieve the light intensity ratio.

[0093] The first angle control unit 350 is used to receive the first recording light 301 and adjust the angle of the first recording light 301 so that the first recording light 301 illuminates the first region 2221 of the substrate 2220. Exemplarily, the first angle control unit 350 may include a rotary motion platform (not shown), a coating reflector (not shown), and a drive controller (not shown). The rotary motion platform may be connected to the coating reflector. The drive controller may drive the rotary motion platform to move, thereby controlling the angle of the coating reflector to adjust the angle of the first recording light 301.

[0094] The second light intensity control unit 340 is used to receive the second sub-beam 3112 and adjust the light intensity of the second sub-beam 3112 to form the second recording light 302. The specific structure of the second light intensity control unit 340 can be found in the description of the first light intensity control unit 330 above, and the specific structure of the second light intensity control unit 340 will not be described again in this application.

[0095] The second light intensity control unit 340 can be located on the laser propagation path of the first laser 310.

[0096] In this embodiment, the first beam splitting unit 320 can reflect part of the first laser 311 to the first light intensity control unit 330, and another part of the first laser 311 can directly irradiate the second light intensity control unit 340.

[0097] The second angle control unit 360 is used to receive the second recording light 302 and adjust the angle of the second recording light 302 so that the second recording light 302 irradiates the first region 2221 of the substrate 2220. The specific structure of the second angle control unit 360 can be found in the description of the first angle control unit 350 above, and the specific structure of the second angle control unit 360 will not be described again in this application.

[0098] The second recording light 302 and the first recording light 301 are respectively used to irradiate opposite sides of the substrate 2220 in the thickness direction, so that the first region 2221 forms the first grating 2223 of the holographic film 222. The holographic film 222 is the structure formed after the substrate 2220 completes the grating fabrication.

[0099] The moving unit 370 is used to connect to the substrate 2220 and move the substrate 2220 so that the first recording light 301 and the second recording light 302 irradiate the second region 2222 of the substrate 2220, thereby forming the second grating 2224 of the holographic film 222 in the second region 2222. Exemplarily, the moving unit 370 may include a fixing clip (not shown) and a displacement platform (not shown). The displacement platform can be fixedly connected to the holographic film 222 via the fixing clip. The displacement platform can drive the holographic film 222 to move. The first angle control unit 350 and the second angle control unit 360 are located on opposite sides of the moving unit 370.

[0100] In this embodiment, the moving unit 370 can control the substrate 2220 to move between the first angle control unit 350 and the second angle control unit 360, so that the first recording light 301 and the second recording light 302 can interfere at any position on the substrate 2220 to form a grating.

[0101] For example, the exposure optical path system 300 may further include a laser shutter unit (not shown), a first reflector 380, a second reflector 381, a third reflector 382, ​​a fourth reflector 383, and a fifth reflector 384. The laser shutter unit may be located between the first laser 310 and the first beam splitting unit 320. The laser shutter unit can control the opening and closing of the first laser 310, thereby controlling the exposure time of the exposure optical path system 300.

[0102] The first reflector 380 is used to reflect the first recording light 301 emitted by the first light intensity control unit 330 to the second reflector 381, and the second reflector 381 reflects the first recording light 301 to the first angle control unit 350.

[0103] The third reflector 382 reflects the second recording light 302 emitted by the second light intensity control unit 340 to the fourth reflector 383, which in turn reflects the second recording light 302 to the fifth reflector 384. The fifth reflector 384 then reflects the second recording light 302 to the second angle control unit 360.

[0104] In this embodiment, the first reflector 380 and the second reflector 381 can be flexibly adjusted to change the direction of light propagation from the first light intensity control unit 330 to the first angle control unit 350, so that the relative positions of the first light intensity control unit 330 and the first angle control unit 350 can be flexibly set. The third reflector 382, ​​the fourth reflector 383, and the fifth reflector 384 can be flexibly adjusted to change the direction of light propagation from the second light intensity control unit 340 to the second angle control unit 360, so that the relative positions of the second light intensity control unit 340 and the second angle control unit 360 can be flexibly set.

[0105] In this embodiment, the exposure optical path system 300 avoids using large optical lenses, instead using a light intensity control unit and an angle control unit to adjust the light intensity and angle of the first recording light 301 and the second recording light 302, so that the first recording light 301 and the second recording light 302 can directly illuminate opposite sides of the substrate 2220 in the thickness direction. The first recording light 301 and the second recording light 302 meet and interfere inside the substrate 2220. In the region of enhanced interference, the light intensity is enhanced, and the film material receives a greater light intensity. In the region of weakened interference, the light intensity is weakened, and the film material receives a smaller light intensity. Since the absorption, reflection, or refraction properties of the substrate 2220 may change due to different light intensities, specific patterns or structures will be formed on the substrate 2220 in the regions of enhanced and weakened interference. These patterns or structures are the basic units of the grating: slits or grooves.

[0106] It is known that currently, convex lenses and other transmissive mirrors are generally used to form coherent light on the substrate, thereby forming a grating on the substrate. However, due to the shape limitations of convex lenses, if multiple gratings need to be fabricated on the same substrate, multiple lenses need to be used during the substrate processing. This results in a longer production process, increases the possibility of production defects in the holographic film material, and consequently affects the production yield of the holographic film material, increasing the production cost of the head-up display device.

[0107] Since the exposure optical path system 300 has a light intensity control unit, an angle control unit, and a movement unit 370, it can theoretically illuminate any area of ​​the substrate 2220 with light of any intensity within the adjustable range at any angle within the adjustable range. The exposure optical path system 300 of this application can directly change the angle, intensity, and incident position of the coherent light without replacing the lens. The substrate 2220 can form the first grating 2223 and the second grating 2224 in the same process, thereby simplifying the preparation process of the holographic film 222, reducing the possibility of production defects in the holographic film 222, improving the production yield of the holographic film 222, and saving production costs for the head-up display device 20 and the vehicle 100.

[0108] In this embodiment, compared to current mainstream traditional liquid crystal lens head-up display systems, the volume holographic head-up display device 20 has less light energy loss, and because it uses a high-power light source, its output image brightness can reach 10,000 nits. Furthermore, a multi-focal surface system can be designed by modulating the beam parameters of the exposure optical path system 300 to achieve imaging at different distances in front of the driver. The head-up display device 20 also has a large field of view, exceeding 35°.

[0109] In another possible implementation, please refer to Figure 11, which is a schematic diagram of another exposure optical path system 300 provided in an embodiment of this application. The exposure optical path system 300 further includes a second laser 390, a third laser 400, a second beam splitting unit 410, and a third beam splitting unit 420. The second laser 390 is used to emit a second laser 391, and the third laser 400 is used to emit a third laser 401. The first laser 311, the second laser 391, and the third laser 401 have different colors. For example, the first laser 311 is red light, the second laser 391 is green light, and the third laser 401 is blue light. The intensity ratio of red light to green light is between 1 and 1.5, and the intensity ratio of blue light to green light is between 1.5 and 2.

[0110] The second beam splitting unit 410 is used to receive the second laser 391 and split the second laser 391 into a third sub-beam 3911 and a fourth sub-beam 3912. The third beam splitting unit 420 is used to receive the third laser 401 and split the third laser 401 into a fifth sub-beam 4011 and a sixth sub-beam 4012.

[0111] The first light intensity control unit 330 is used to receive the first sub-beam 3111, the third sub-beam 3911 and the fifth sub-beam 4011, and adjust the light intensity of the first sub-beam 3111, the third sub-beam 3911 and the fifth sub-beam 4011 to form the third recording light 303. The second light intensity control unit 340 is used to receive the second sub-beam 3112, the fourth sub-beam 3912 and the sixth sub-beam 4012, and adjust the light intensity of the second sub-beam 3112, the fourth sub-beam 3912 and the sixth sub-beam 4012 to form the fourth recording light 304.

[0112] In this embodiment, by adjusting the intensity ratio and angle parameters of the recording light in the exposure optical path system 300, grating stripes with different periods and tilt angles are formed inside the substrate material 2220, resulting in holographic films 222 with different focal planes. These films can reflect and image light of various wavelengths, and can reflect and image off-axis or on the same optical axis while exhibiting near-total transmission of other wavelengths of light. They possess the characteristics of almost total reflection of selected wavelengths of light and total transmission of non-selected wavelengths of light. Thus, the holographic film 222 can reflect projected light to form an image, while directly transmitting other rays of sunlight without affecting the image clarity.

[0113] In other possible embodiments, unlike the exposure optical path system that includes one laser (first laser 310) and the exposure optical path system that includes three lasers (first laser 310, second laser 390, and third laser 400), the exposure optical path system may also include only two lasers. The two lasers can be the first laser 310 and the second laser 390 described above. In this embodiment, the configuration of the first laser 310 can be found in the detailed description of the first laser 310 above. Similarly, the configuration of the second laser 390 can be found in the detailed description of the second laser 390 above. This embodiment will not elaborate further on the first laser 310 and the second laser 390. In this embodiment, the first laser 310 and the second laser 390 can emit monochromatic light or mixed-color light.

[0114] The holographic film 222 prepared by the exposure optical path system 300 provided in this application embodiment forms a periodic grating inside. The angle β between the first grating 2223 and / or the second grating 2224 and the surface of the holographic film 222 ranges from 0-35°, 42-55°, and 60-85° (inclusive of the endpoints). The stripe spacing between the first grating 2223 and the second grating 2224 can be between 200nm and 400nm (inclusive of the endpoints 200nm and 400nm).

[0115] Generally, the stripe spacing of the first grating 2223 and the second grating 2224 is approximately half the wavelength of the recorded light, thus the photosensitive range of the holographic film 222 can be between 400nm and 650nm (inclusive of the endpoint values ​​400nm-650nm). The thickness of the holographic film 222 can range from 15μm to 120μm. In some specific embodiments, the thickness range of the holographic film 222 can be between 15μm-55μm, 60μm-80μm, and 90-120μm (all inclusive of the endpoint values). The material of the holographic film 222 can include one or a combination of photopolymer materials, silver halide materials, polymer liquid crystals, and gelatin dichromate. The holographic film 222 has a beam-expanding function. When the light from the image generating unit 21 shines on the holographic film 222, the holographic film 222 can enlarge the imaging area, thereby replacing the function of the freeform mirror in a traditional head-up display system. This reduces the overall size of the head-up display device 20.

[0116] When the projection light from the image generating unit 21 shines on the holographic film 222 of the car window glass 22, the first region 2221 and the second region 2222 can reflect the projection light, forming a virtual image at the driver's eye position. At the same time, the view outside the glass substrate 221 is fully transmissive. At this time, the distance from the imaging plane of the holographic film 222 to the eye depends on the maximum angle of the exposure light path. The reflected image of the first region 2221 can display dashboard information such as speed. The distance between the projected virtual image of the first region 2221 and the human eye can be between 0.2m-0.5m, or 0.5m-1.5m, or 1.5m-3m (all including the endpoints). The reflected image of the second region 2222 can display navigation, road assistance, and other information. The distance between the projected virtual image in the second region 2222 and the human eye can be 3m-4.5m, or 4.5m-7.5m, or 7.5m-9.5m, or 9.5m-11m, or greater than 11m (all including the endpoint values).

[0117] In this embodiment, by adjusting the intensity ratio of red, green and blue light, the spectral bandwidth of the grating formed by the interference of the third recording light 303 and the fourth recording light 304 is increased, so that the first grating 2223 and the second grating 2224 can reflect light of wavelengths in the visible light range, thereby making the colors of the images of the first region 2221 and the second region 2222 richer.

[0118] The exposure optical path system 300 may also include a first reflector 380, a second reflector 381, a third reflector 382, ​​a fourth reflector 383, a fifth reflector 384, a sixth reflector 385, a seventh reflector 386, an eighth reflector 387, and a ninth reflector 388.

[0119] The third recording light 303 includes red light, green light and blue light. The first reflector 380 is used to reflect red light, the second reflector 381 is used to reflect green light and the third reflector 382 is used to reflect blue light, so that the red light, green light and blue light are mixed to form white light and reflected to the fourth reflector 383. The fourth reflector 383 reflects the white light to the first angle control unit 350.

[0120] The fourth recording light 304 includes red light, green light and blue light. The fifth reflector 384 is used to reflect red light, the sixth reflector 385 is used to reflect green light and the seventh reflector 386 is used to reflect blue light, so that the red light, green light and blue light are mixed to form white light and reflected to the eighth reflector 387. The eighth reflector 387 reflects the white light to the ninth reflector 388, and the ninth reflector 388 reflects the white light to the first angle control unit 350.

[0121] This application also adjusts the intensity ratio of the three wavelengths of the first laser 311, the second laser 391, and the third laser 401, thereby improving the diffraction efficiency of the holographic film 222. Please refer to Table 1.

[0122] Table 1. Test results of diffraction efficiency for different RGB light intensity ratios

[0123] As shown in Table 1, adjusting the ratio of red, green, and blue light intensities can improve the diffraction efficiency of the holographic film 222, resulting in clearer images of the first region 2221 and the second region 2222 of the holographic film 222. This further promotes the application of the volume holographic film 222 in head-up displays.

[0124] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A vehicle glazing, characterised in that, It includes a glass substrate and a holographic film. The glass substrate includes an outer glass plate, an inner glass plate, and an intermediate layer. The outer glass plate and the inner glass plate are stacked together, and the intermediate layer connects the outer glass plate and the inner glass plate. The holographic film is located between the outer glass plate and the intermediate layer, or the holographic film is located between the intermediate layer and the inner glass plate. The holographic film includes a first region and a second region. The first region has a first grating, and the second region has a second grating. The angle between the first grating and the surface of the holographic film is different from the angle between the second grating and the surface of the holographic film.

2. The vehicle glazing of claim 1, wherein, The window glass also includes a first protective film, which is located between the intermediate layer and the holographic film.

3. The glazing according to claim 2, wherein, The window glass also includes a second protective film, which is attached to the surface of the holographic film material opposite to the first protective film.

4. The glazing according to claim 3, wherein, The number of intermediate layers is two, one intermediate layer is connected to the surface of the first protective film opposite to the holographic film material, and the other intermediate layer is connected to the surface of the second protective film opposite to the holographic film material.

5. The glazing according to claim 4, wherein, The two intermediate layers are a first intermediate layer and a second intermediate layer, and the thickness of the first intermediate layer and the thickness of the second intermediate layer can be 0.76mm±0.02mm, or 0.38mm±0.02mm, or 200um~380um, or 100um~200um, or 50um~100um, or 50um; The adhesion between the first intermediate layer and the second intermediate layer is greater than or equal to 10 MPa.

6. The vehicle glazing of claim 5, wherein, The holographic film is connected between the first intermediate layer and the second intermediate layer. A first protective film may be provided between the holographic film and the first intermediate layer, and a second protective film may be provided between the holographic film and the second intermediate layer. The light transmittance of the first protective film and the second protective film can be greater than or equal to 90%, or the light transmittance of the first protective film and the second protective film can be greater than or equal to 95%. The haze of the first protective film and the second protective film may be less than or equal to 1%, or the haze of the first protective film and the second protective film may be less than or equal to 0.5%.

7. The glazing according to any one of claims 1 to 6, characterized in that, Both the first grating and the second grating include periodic stripes. The angle between the periodic stripes of the first grating and the surface of the holographic film is within one of the ranges of 0–35°, 42–55°, and 60–85°. The angle between the periodic stripes of the second grating and the surface of the holographic film is within another range of 0–35°, 42–55°, and 60–85°.

8. The glazing according to claim 7, wherein, The stripe spacing of the periodic stripes of the first grating is in the range of 200nm to 400nm.

9. The glazing according to any one of claims 1 to 6, characterized in that, The thickness of the holographic film is in the range of 15μm-120μm.

10. The vehicle glazing of claim 1, wherein, The outer glass plate and the inner glass plate contain 0-0.1% iron oxide (Fe2O3), or the content of iron oxide (Fe2O3) in the outer glass plate and the inner glass plate is less than or equal to 0.09%, or less than or equal to 0.08%, or less than or equal to 0.07%, or less than or equal to 0.05%, or less than or equal to 0.04%, or less than or equal to 0.03%, or less than or equal to 0.02%, or less than or equal to 0.015%, or less than or equal to 0.01%.

11. A head-up display device, characterized by comprising: The device includes an image generating unit and a vehicle window glass as described in any one of claims 1-10. The image generating unit is used to project light onto a first region and a second region of the holographic film, and the first region and the second region reflect the projected light, such that the images corresponding to the first region and the second region are focused at different depths of the holographic film.

12. A vehicle characterized by comprising: It includes a vehicle body and a head-up display device as described in claim 11, the head-up display device being connected to the vehicle body.

13. An exposure light path system for a holographic film material, characterized by comprising: For preparing holographic films, the exposure optical path system includes a first laser, a first beam splitting unit, a first light intensity control unit, a second light intensity control unit, a first angle control unit, a second angle control unit, and a moving unit; The first laser is used to emit a first laser beam; The first beam splitting unit is used to receive the first laser beam and split the first laser beam into a first sub-beam and a second sub-beam; The first light intensity control unit is used to receive the first sub-beam and adjust the light intensity of the first sub-beam to form a first recording light; The first angle control unit is used to receive the first recording light and adjust the angle of the first recording light so that the first recording light illuminates a first area of ​​the substrate; The second light intensity control unit is used to receive the second sub-beam and adjust the light intensity of the second sub-beam to form a second recording light; The second angle control unit is used to receive the second recording light and adjust the angle of the second recording light so that the second recording light illuminates the first area of ​​the substrate; The second recording light and the first recording light are respectively used to irradiate opposite sides of the substrate in the thickness direction, so that the first region forms the first grating of the holographic film material; The moving unit is used to connect to the substrate and move the substrate so that the first recording light and the second recording light irradiate a second area of ​​the substrate, so that the second area forms a second grating of holographic film.

14. The exposure light path system according to claim 13, wherein The exposure optical path system also includes a second laser, which is used to emit a second laser, and the first laser and the second laser are of different colors; The exposure optical path system further includes a second beam splitting unit, which is used to receive the second laser and split the second laser into a third sub-beam and a fourth sub-beam. The first light intensity control unit is used to receive the first sub-beam and the third sub-beam, and adjust the light intensity of the first sub-beam and the third sub-beam to form a third recording light. The second light intensity control unit is used to receive the second sub-beam and the fourth sub-beam, and adjust the light intensity of the second sub-beam and the fourth sub-beam to form a fourth recording light.

15. The exposure light path system according to claim 14, wherein The exposure optical path system also includes a third laser, which is used to emit a third laser, and the first laser, the second laser and the third laser are different colors; The exposure optical path system also includes a third beam splitting unit, which is used to receive the third laser and split the third laser into a fifth sub-beam and a sixth sub-beam. The first light intensity control unit is used to receive the first sub-beam, the third sub-beam, and the fifth sub-beam, and adjust the light intensity of the first sub-beam, the third sub-beam, and the fifth sub-beam to form a third recording light. The second light intensity control unit is used to receive the second sub-beam, the fourth sub-beam, and the sixth sub-beam, and adjust the light intensity of the second sub-beam, the fourth sub-beam, and the sixth sub-beam to form a fourth recording light.

16. The exposure light path system according to claim 15, wherein The first laser is red light, the second laser is green light, and the third laser is blue light. The intensity ratio of the red light to the green light is between 1 and 1.5, and the intensity ratio of the blue light to the green light is between 1.5 and 2.

17. The exposure light path system according to claim 13, wherein The exposure optical path system further includes a first reflector, which is used to reflect the first recording light emitted by the first light intensity control unit toward the first angle control unit.

18. The exposure light path system according to claim 16, wherein The exposure optical path system further includes a first reflector, a second reflector, and a third reflector; The third recording light includes red light, green light, and blue light. The first reflector is used to reflect the red light, the second reflector is used to reflect the green light, and the third reflector is used to reflect the blue light, so that the red light, the green light, and the blue light are mixed to form white light, which is then reflected to the first angle control unit.

19. The exposure light path system according to claim 13, wherein The first angle control unit and the second angle control unit are located on opposite sides of the moving unit.

20. The exposure light path system according to any one of claims 13-19, characterized by, The second light intensity control unit is located on the laser propagation path of the first laser.

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