Laminated glass, projection system and vehicle

Abstract

A laminated glass, a projection system and a vehicle. An interlayer of the laminated glass comprises a coupling-in region and a coupling-out region. Projection light can enter the coupling-in region from a fourth surface, and, after being reflected by the coupling-in region, the projection light can be reflected back and forth between the interlayer and the fourth surface, so that the projection light propagates in a second glass plate; in addition, the projection light propagating in the second glass plate can be emitted to the coupling-out region, and, after being reflected by the coupling-out region, the projection light can pass through the fourth surface, so as to be emitted out of the second glass plate. By configuring the refractive index of a polymer layer to be less than the refractive index of the second glass plate and the refractive index of air to be less than the refractive index of the second glass plate, the second glass plate forms an optical waveguide structure, such that the projection light can propagate in the second glass plate; in addition, by cooperatively providing the coupling-in region and the coupling-out region, the projection light undergoes total reflection in the second glass plate, thereby relieving or even eliminating the ghosting phenomenon, and improving the display effect of the laminated glass.

Description

Laminated glass, projection systems and vehicles

[0001] This disclosure claims priority to Chinese Patent Application No. 202411432753.X, filed on October 14, 2024, entitled "Laminated Glass, Projection System and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of glass technology, specifically relating to laminated glass, projection systems, and vehicles. Background Technology

[0003] In vehicles, head-up display (HUD) technology can project an image containing driving information directly in front of the glass through an optical engine, so that users do not need to look down at the instrument panel while driving, which greatly improves driving convenience and safety.

[0004] Traditional head-up display (HUD) technology uses laminated glass as the reflective surface, directing projected light through the glass for a single reflection before it reaches the user's eyes. Because laminated glass consists of an outer glass panel, an intermediate layer, and an inner glass panel, its structure dictates that direct projection reflection inevitably results in secondary reflections at the interfaces between the outer, intermediate, and inner glass panels and the air, in addition to the primary reflective surface (the fourth surface). The image formed by these secondary reflections is called a "ghost image," which typically overlaps with the primary image. This overlap causes the actual image observed by the user to appear blurry, affecting the display quality of the laminated glass and reducing the user experience. Summary of the Invention

[0005] In view of this, the first aspect of this application provides a laminated glass, the laminated glass comprising a first glass plate, an intermediate layer, and a second glass plate, the first glass plate having a first surface and a second surface, the second glass plate having a third surface and a fourth surface, and the intermediate layer connecting the second surface and the third surface;

[0006] The refractive index of the intermediate layer is less than that of the second glass plate, and the intermediate layer includes a coupling-in region and a coupling-out region spaced apart. The coupling-in region is used to receive the projected light rays incident from the fourth surface and change the propagation direction of the projected light rays. The coupling-out region is used to receive the projected light rays propagating in the second glass plate and change the propagation direction of the projected light rays.

[0007] The projected light rays can enter the coupling area from the fourth surface. After being reflected by the coupling area, the projected light rays can be reflected back and forth between the intermediate layer and the fourth surface, so that the projected light rays can propagate within the second glass plate. Furthermore, the projected light rays propagating within the second glass plate can reach the coupling area. After being reflected by the coupling area, the projected light rays can pass through the fourth surface and exit the second glass plate.

[0008] The intermediate layer includes a polymer layer, a first holographic element disposed in the coupling region, and a second holographic element disposed in the coupling region. The polymer layer connects the second surface and the third surface. The refractive index of the polymer layer is less than the refractive index of the second glass plate. The first holographic element and the second holographic element are fixed to the polymer layer and are disposed facing the third surface. The first holographic element and the second holographic element are spaced apart.

[0009] The refractive index of the polymer layer is ≤1.52, or ≤1.40, or ≤1.30, or ≤1.20.

[0010] Wherein, the first holographic element is used to give the projected light a first angle θ1, the first angle θ1 being the angle between the light reflected by the first holographic element and the normal direction of the second glass plate;

[0011] The first angle θ1 satisfies the following formula: θ1≥arcsin(n2 / n1); where n1 is the refractive index of the second glass plate, and n2 is the maximum value of the refractive index of the polymer layer and the refractive index of air.

[0012] The projected light rays are generated by a projection device, and the incident direction of the projected light rays from the projection device to the fourth surface is perpendicular to the fourth surface.

[0013] Wherein, the second holographic element is used to give the projected light a second angle θ2, the second angle θ2 being the angle between the light reflected by the second holographic element and the normal direction of the second glass plate, and the projected light also has a third angle θ3, the third angle θ3 being the angle between the light emitted from the second glass plate and the normal direction of the second glass plate;

[0014] The second angle θ2 and the third angle θ3 satisfy the following formula: sinθ2×n1=sinθ3×n3, and 1.52×sinθ2=sinθ3; where n1 is the refractive index of the second glass plate and n3 is the refractive index of air.

[0015] Wherein, the area of ​​the first holographic element is greater than or equal to the area of ​​the projected light rays incident on the fourth surface; and / or, the area of ​​the second holographic element is greater than the area of ​​the first holographic element.

[0016] The intermediate layer further includes an auxiliary coupling region, which is located on the side of the coupling-out region away from the coupling-in region. The projected light rays are reflected sequentially by the coupling-out region and the fourth surface to form crosstalk light rays. The auxiliary coupling region is used to receive the crosstalk light rays and change the propagation direction of the crosstalk light rays.

[0017] The crosstalk light can be directed to the auxiliary coupling region, and after being reflected by the auxiliary coupling region, the crosstalk light can be reflected back and forth between the intermediate layer and the fourth surface, so that the crosstalk light can propagate within the second glass plate.

[0018] The intermediate layer further includes a third holographic element disposed in the auxiliary coupling region. The third holographic element is fixed to the polymer layer and faces the third surface. The third holographic element is disposed on the side of the second holographic element away from the first holographic element.

[0019] The third holographic element is used to give the crosstalk light a fourth angle θ4, which is the angle between the light reflected by the third holographic element and the normal direction of the second glass plate.

[0020] The fourth angle θ4 satisfies the following formula: θ4≥arcsin(n2 / n1); where n1 is the refractive index of the second glass plate, and n2 is the maximum value between the refractive index of the polymer layer and the refractive index of air.

[0021] The laminated glass has a light-transmitting area and a shielding area, wherein the visible light transmittance of the light-transmitting area is ≥70%, and the visible light transmittance of the shielding area is ≤5%.

[0022] The first holographic element is disposed in the shielding area, and the second holographic element and the third holographic element are both disposed in the light-transmitting area, with the second holographic element connected to the third holographic element.

[0023] The first holographic element, the second holographic element, and the third holographic element constitute a holographic element group. The laminated glass has a left-hand drive area and a right-hand drive area arranged along the length of the laminated glass. One holographic element group is disposed in the left-hand drive area, and the other holographic element group is disposed in the right-hand drive area.

[0024] Wherein, along the height direction of the laminated glass, the height of the third holographic element is greater than the height of the second holographic element, and the height of the second holographic element is greater than the height of the first holographic element.

[0025] Along the height direction of the laminated glass, there is a distance D between the first holographic element and the second holographic element, and the distance D satisfies the following formula: D=2×n×d×tanθ1; where n is a positive integer, d is the thickness of the second glass plate, and θ1 is the angle between the light reflected by the first holographic element and the normal direction of the second glass plate.

[0026] The first holographic element, the second holographic element, and the third holographic element are embedded in the polymer layer, and the thicknesses of the first holographic element, the second holographic element, the third holographic element, and the polymer layer are equal.

[0027] The thickness of the polymer layer is 0.20mm to 1mm, or 0.30mm to 0.90mm, or 0.40mm to 0.80mm.

[0028] Wherein, the absolute value of the difference between the refractive index of the first holographic element and the refractive index of the polymer layer is 0 to 0.01;

[0029] And / or, the absolute value of the difference between the refractive index of the second holographic element and the refractive index of the polymer layer is 0 to 0.01;

[0030] And / or, the absolute value of the difference between the refractive index of the third holographic element and the refractive index of the polymer layer is 0 to 0.01.

[0031] The laminated glass further includes a shielding layer disposed on the second surface and / or the fourth surface, wherein the shielding layer is disposed within the shielding area.

[0032] A second aspect of this application provides a projection system, the projection system including a projection device and a laminated glass as provided in the first aspect of this application, the projection device being used to generate projection light, the projection light being projected onto the fourth surface, and the laminated glass reflecting the projection light to form a display image.

[0033] A third aspect of this application provides a vehicle, the vehicle including a body and a projection system provided in the second aspect of this application, wherein the projection device of the projection system is installed inside the body and the laminated glass of the projection system is installed at an opening in the body.

[0034] The laminated glass, projection system, and vehicle provided in this application, by setting an intermediate layer, wherein the refractive index of the polymer layer is lower than that of the second glass plate, and the refractive index of air is lower than that of the second glass plate, allows the second glass plate to form a light waveguide structure, which can also be understood as a light guide structure, enabling the projected light to propagate within the second glass plate. Furthermore, by using a first holographic element to change the direction of the projected light, causing total internal reflection within the second glass plate, and then using a second holographic element to further change the direction of the projected light, allowing it to exit the second glass plate and enter the eye, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass. In addition, a third holographic element is set to change the direction of crosstalk light, causing crosstalk light to undergo total internal reflection within the second glass plate, thereby preventing crosstalk light from escaping at the position of the main image, further reducing or even eliminating ghosting, further improving the display effect of the laminated glass, and further enhancing the user experience. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0036] Figure 1 is a cross-sectional view of a laminated glass provided in one embodiment of this application.

[0037] Figure 2 is a magnified view of a portion of Figure 1.

[0038] Figure 3 is another enlarged view of a portion of Figure 1.

[0039] Figure 4 is a schematic diagram of the structure of the laminated glass provided in one embodiment of this application.

[0040] Labeling description: laminated glass 10, light-transmitting area 101, shielding area 102, left-hand drive area 103, right-hand drive area 104, first glass plate 11, first surface 111, second surface 112, intermediate layer 12, polymer layer 121, first holographic element 122, second holographic element 123, third holographic element 124, second glass plate 13, third surface 131, fourth surface 132, projection device 20. Detailed Implementation

[0041] The following are preferred embodiments of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0042] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0043] In this application, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0044] In this application, "one or more" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0045] The value of x in the chemical formula: If it is clearly defined, the defined range shall prevail. If it is not clearly defined, it can be determined according to the stoichiometric, substoichiometric, or superstoichiometric deposition methods used in the magnetron sputtering process.

[0046] Refractive index: The refractive index measured at a wavelength of 550 nm.

[0047] As shown in Figures 1, 2 and 3, this application provides a laminated glass 10, which includes a first glass plate 11, an intermediate layer 12 and a second glass plate 13. The first glass plate 11 has a first surface 111 and a second surface 112, and the second glass plate 13 has a third surface 131 and a fourth surface 132. The intermediate layer 12 connects the second surface 112 and the third surface 131.

[0048] The refractive index of the intermediate layer 12 is less than that of the second glass plate 13, and the intermediate layer 12 includes a coupling-in region and a coupling-out region spaced apart. The coupling-in region is used to receive the projected light rays incident from the fourth surface 132 and change the propagation direction of the projected light rays. The coupling-out region is used to receive the projected light rays propagating in the second glass plate 13 and change the propagation direction of the projected light rays.

[0049] The projected light rays can enter the coupling region from the fourth surface 132. After being reflected by the coupling region, the projected light rays can be reflected back and forth between the intermediate layer 12 and the fourth surface 132, so that the projected light rays can propagate within the second glass plate 13. Furthermore, the projected light rays propagating within the second glass plate 13 can reach the coupling region. After being reflected by the coupling region, the projected light rays can pass through the fourth surface 132 and exit the second glass plate 13.

[0050] The projected light is generated by the projection device 20 and incident on the laminated glass 10. The laminated glass 10 reflects the projected light to form a display image that can be observed by people inside the vehicle. In particular, for the driver, the image can be observed without looking down, which improves the driver's field of vision and allows the driver to observe the external situation for a longer period of time. At the same time, it is easier to obtain the necessary information for assisted driving, which greatly improves driving safety. Thus, it can partially or even completely replace the traditional instrument panel, or even eliminate the traditional instrument panel.

[0051] The image formed by the reflection of projected light through the laminated glass 10 can display vehicle driving information, various patterns, or play videos, and can be used in various scenarios such as welcoming guests, creating an atmosphere, watching movies, and office work. Optionally, it can be used to display driving parameters, including vehicle speed, engine speed, fuel consumption, tire pressure, warning information, and mileage. It can also be used to display weather temperature, entertainment information, and can be used for dynamic navigation, night vision, and real-view maps.

[0052] The first glass plate 11 serves as the outer glass plate of the laminated glass 10. The first glass plate 11 has a first surface 111 and a second surface 112. The first surface 111 is away from the intermediate layer 12 and in contact with the external environment of the vehicle, while the second surface 112 is close to the intermediate layer 12. The second glass plate 13 serves as the inner glass plate of the laminated glass 10. The second glass plate 13 has a third surface 131 and a fourth surface 132. The third surface 131 is close to the intermediate layer 12, while the fourth surface 132 is away from the intermediate layer 12 and in contact with the internal environment of the vehicle. The intermediate layer 12 connects the second surface 112 and the third surface 131.

[0053] The first glass plate 11 is transparent or tinted glass, with a thickness of 1.6mm to 2.1mm and a visible light transmittance greater than or equal to 80%. The second glass plate 13 is also transparent or tinted glass, with a thickness of 1.6mm to 2.1mm and a visible light transmittance greater than or equal to 80%. For example, the first glass plate 11 can be 2.1mm thick transparent glass with a visible light transmittance of 89%, and the second glass plate 13 can be 1.6mm thick green glass with a visible light transmittance of 83%, or 2.1mm thick green glass with a visible light transmittance of 80%. The refractive indices of the first glass plate 11 and the second glass plate 13 are 1.45 to 1.90, specifically 1.48, 1.52, 1.56, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, or 1.90, etc.

[0054] The refractive index of the intermediate layer 12 is less than that of the second glass plate 13. The refractive index of the intermediate layer 12 is ≤1.52, specifically examples include 1.52, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, 1.10, or 1.05, etc. The refractive index of air is approximately 1. The intermediate layer 12 / second glass plate 13 / air form a low refractive index layer / high refractive index layer / low refractive index layer, making the second glass plate 13 form an optical waveguide structure, which can also be understood as a light guiding structure, confining light to propagate within a specific direction and range, allowing the projected light to propagate within the second glass plate 13.

[0055] Specifically, after the projected light enters the coupling area from the fourth surface 132, it is reflected by the intermediate layer 12 and then reflected back to the fourth surface 132. The projected light then reflects back and forth between the intermediate layer 12 and the fourth surface 132, repeating the above process. This continues until the projected light, after being reflected by the coupling area, passes through the fourth surface 132, exits the second glass plate 13, and enters the eye, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass 10. The projected light is shown as L1 in Figure 1. By adjusting the propagation direction of the projected light within the second glass plate 13, total internal reflection can be achieved within the second glass plate 13.

[0056] In related technologies, the laminated glass 10 uses a PVB film with a wedge-shaped angle to make the two reflected images overlap as much as possible to eliminate ghosting, but this cannot fundamentally solve the ghosting phenomenon. However, this application, by setting a holographic waveguide structure in the laminated glass 10, can replace the wedge-shaped PVB film laminated glass 10 in related technologies, effectively eliminating the influence of ghosting, providing higher imaging quality, and adapting to different shapes of the laminated glass 10, thus offering flexibility.

[0057] The structure of the intermediate layer 12 is described in detail below. The intermediate layer 12 includes a polymer layer 121, a first holographic element 122 disposed in the coupling region, and a second holographic element 123 disposed in the coupling region. The polymer layer 121 connects the second surface 112 and the third surface 131. The refractive index of the polymer layer 121 is less than the refractive index of the second glass plate 13. The first holographic element 122 and the second holographic element 123 are fixed to the polymer layer 121 and are disposed facing the third surface 131. The first holographic element 122 and the second holographic element 123 are spaced apart.

[0058] The first holographic element 122 is used to receive the projected light rays incident from the fourth surface 132 and change the propagation direction of the projected light rays so that the projected light rays propagate within the second glass plate 13. The second holographic element 123 is used to receive the projected light rays propagating within the second glass plate 13 and change the propagation direction of the projected light rays so that the projected light rays exit the second glass plate 13. The second holographic element 123 is also used to amplify the projected light rays.

[0059] A polymer layer 121 is disposed between the first glass plate 11 and the second glass plate 13, connecting the second surface 112 and the third surface 131. The material of the polymer layer 121 may include one or more of the following materials: polycarbonate (PC), polyvinyl chloride (PVC), polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyacrylate (PA), polymethyl methacrylate (PMMA), polyurethane (PUR), ionomer polymer film (SGP), etc. The refractive index of the polymer layer 121 is ≤1.52, specifically 1.52, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, 1.10, or 1.05, etc. Preferably, the refractive index of the polymer layer 121 is ≤1.40; more preferably, the refractive index of the polymer layer 121 is ≤1.30; and even more preferably, the refractive index of the polymer layer 121 is ≤1.20. The thickness of the polymer layer 121 is 0.20 mm to 1 mm, specifically, examples include 0.20 mm, 0.30 mm, 0.40 mm, 0.50 mm, 0.60 mm, 0.70 mm, 0.80 mm, 0.90 mm, or 1 mm, etc. Preferably, the thickness of the polymer layer 121 is 0.30 mm to 0.90 mm, more preferably, the thickness of the polymer layer 121 is 0.40 mm to 0.80 mm. For example, the thickness of the polymer layer 121 is 0.38 mm or 0.76 mm. The specific thickness of the polymer layer 121 can be adjusted according to product requirements or user requirements.

[0060] The first holographic element 122 is a diffractive optical element whose working principle is based on the principle of diffraction, rather than the refraction or reflection laws of traditional optical elements. The first holographic element 122 can be a holographic optical element (HOE) thin film. The first holographic element 122 can receive the projected light rays incident from the fourth surface 132 and change the direction of the projected light rays, so that the projected light rays undergo total internal reflection within the second glass plate 13.

[0061] The first holographic element 122 is fixed to the polymer layer 121, for example, by bonding the first holographic element 122 to the polymer layer 121. An adhesive with high transparency is used to bond the first holographic element 122 to the polymer layer 121, ensuring that the visibility of the laminated glass 10 is not affected, thereby reducing the sense of boundary. The adhesive also has good adhesion, firmly bonding the polymer layer 121 and the first holographic element 122 together, ensuring the stability and durability of the laminated glass 10. The adhesive material can be vinyl acetate (EVA), polyurethane (PU), etc. The first holographic element 122 is embedded in the polymer layer 121 and connected to the third surface 131; the first holographic element 122 can also be connected to the second surface 112.

[0062] The first holographic element 122 is used to give the projected light a first angle θ1, where θ1 is the angle between the light reflected from the first holographic element 122 and the normal direction of the second glass plate 13. The first angle θ1 satisfies the following formula: θ1 ≥ arcsin(n2 / n1); where n1 is the refractive index of the second glass plate 13, and n2 is the maximum of the refractive index of the polymer layer 121 and the refractive index of air. By limiting the incident angle of the projected light to the first angle θ1 using the first holographic element 122, the incident angle of the projected light is made greater than the critical angle of total internal reflection in the optical waveguide. Due to the total internal reflection effect, the projected light can propagate within the optical waveguide structure, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass 10.

[0063] Furthermore, the projected light rays are generated by the projection device 20, and the incident direction of the projected light rays from the projection device 20 to the fourth surface 132 is perpendicular to the fourth surface 132. This can also be understood as the projected light rays incident on the fourth surface 132 at a 90° incident angle. By limiting the incident angle of the projected light rays from the projection device 20 to the fourth surface 132, ghosting caused by reflections of the incident image generated by the projection device 20 on the fourth surface 132 can be avoided. Specifically, the projected light rays enter the fourth surface 132 perpendicularly and then strike the first holographic element 122.

[0064] The second holographic element 123 is a diffractive optical element whose working principle is based on the principle of diffraction, rather than the refraction or reflection laws of traditional optical elements. The second holographic element 123 can be a holographic optical element HOE thin film. The second holographic element 123 can receive projected light rays propagating within the second glass plate 13 and change the direction of the projected light rays, causing them to exit the second glass plate 13. The second holographic element 123 can also amplify the projected light rays.

[0065] The second holographic element 123 is fixed to the polymer layer 121, for example, by bonding the second holographic element 123 to the polymer layer 121. An adhesive with high transparency is used to bond the second holographic element 123 to the polymer layer 121, ensuring that the visibility of the laminated glass 10 is not affected, thereby reducing the sense of boundary. The adhesive also has good adhesion, firmly bonding the polymer layer 121 and the second holographic element 123 together, ensuring the stability and durability of the laminated glass 10. The adhesive material can be vinyl acetate (EVA), polyurethane (PU), etc. The second holographic element 123 is embedded in the polymer layer 121 and connected to the third surface 131; the second holographic element 123 can also be connected to the second surface 112.

[0066] The second holographic element 123 is used to give the projected light a second angle θ2, which is the angle between the light reflected by the second holographic element 123 and the normal direction of the second glass plate 13. The projected light also has a third angle θ3, which is the angle between the light exiting the second glass plate 13 and the normal direction of the second glass plate 13. The second angle θ2 and the third angle θ3 satisfy the following formula: sinθ2×n1=sinθ3×n3, and 1.52×sinθ2=sinθ3; where n1 is the refractive index of the second glass plate 13, and n3 is the refractive index of air. By changing the direction of the projected light, the second holographic element 123 gives the projected light a second angle θ2, thereby eliminating total internal reflection in the second glass plate 13 and allowing it to exit the second glass plate 13 and enter the human eye. The changed angle is related to the position of the human eye, providing flexibility. Meanwhile, the second holographic element 123 also serves to magnify the image, further improving the display effect of the laminated glass 10.

[0067] The area of ​​the first holographic element 122 is greater than or equal to the area of ​​the projected light rays incident on the fourth surface 132. Matching the area of ​​the first holographic element 122 with the area of ​​the projected light rays incident on the fourth surface 132 is beneficial for the first holographic element 122 to receive and reflect more projected light rays, thereby improving the display effect of the laminated glass 10.

[0068] And / or, the area of ​​the second holographic element 123 is larger than the area of ​​the first holographic element 122, which is beneficial for the second holographic element 123 to receive and reflect more projected light, thereby improving the display effect of the laminated glass 10.

[0069] In one embodiment, the intermediate layer 12 further includes an auxiliary coupling region, which is located on the side of the coupling-out region away from the coupling-in region; the projected light is reflected sequentially by the coupling-out region and the fourth surface 132 to form crosstalk light, and the auxiliary coupling region is used to receive the crosstalk light and change the propagation direction of the crosstalk light;

[0070] The crosstalk light rays can reach the auxiliary coupling region. After being reflected by the auxiliary coupling region, the crosstalk light rays can be reflected back and forth between the intermediate layer 12 and the fourth surface 132, so that the crosstalk light rays can propagate within the second glass plate 13. The crosstalk light rays are shown as L2 in Figure 1.

[0071] This embodiment sets up an auxiliary coupling area in conjunction with the coupling-out area to allow crosstalk light to propagate within the second glass plate 13, thereby causing total internal reflection of the crosstalk light within the second glass plate 13. This prevents the crosstalk light from escaping at the position of the main image, further reducing or even eliminating ghosting phenomena, further improving the display effect of the laminated glass 10, and further enhancing the user experience.

[0072] The intermediate layer 12 further includes a third holographic element 124 disposed in the auxiliary coupling region. The third holographic element 124 is fixed to the polymer layer 121 and is disposed facing the third surface 131. The third holographic element 124 is disposed on the side of the second holographic element 123 away from the first holographic element 122.

[0073] The projected light rays are reflected sequentially by the second holographic element 123 and the fourth surface 132 to form crosstalk light rays. The third holographic element 124 is used to receive the crosstalk light rays and change the propagation direction of the crosstalk light rays so that the crosstalk light rays propagate within the second glass plate 13.

[0074] The third holographic element 124 is a diffractive optical element whose working principle is based on the principle of diffraction, rather than the refraction or reflection laws of traditional optical elements. The third holographic element 124 can be a holographic optical element HOE thin film. The third holographic element 124 can receive crosstalk light and change the direction of the crosstalk light, so that the crosstalk light undergoes total internal reflection within the second glass plate 13.

[0075] The third holographic element 124 is fixed to the polymer layer 121, for example, by bonding the third holographic element 124 to the polymer layer 121. An adhesive with high transparency is used to bond the third holographic element 124 to the polymer layer 121, ensuring that the visibility of the laminated glass 10 is not affected, thereby reducing the sense of boundary. The adhesive also has good adhesion, firmly bonding the polymer layer 121 and the third holographic element 124 together, ensuring the stability and durability of the laminated glass 10. The adhesive material can be vinyl acetate (EVA), polyurethane (PU), etc. The third holographic element 124 is embedded in the polymer layer 121 and connected to the third surface 131. The third holographic element 124 can also be connected to the second surface 112. The third holographic element 124 is farther away from the first holographic element 122 than the second holographic element 123, and the third holographic element 124 is connected to the second holographic element 123.

[0076] The third holographic element 124 is used to give the crosstalk light a fourth angle θ4, which is the angle between the light reflected by the third holographic element 124 and the normal direction of the second glass plate 13. The fourth angle θ4 satisfies the following formula: θ4≥arcsin(n2 / n1); where n1 is the refractive index of the second glass plate 13, and n2 is the maximum value between the refractive index of the polymer layer 121 and the refractive index of air.

[0077] Because the portion of the projected light reflected by the second holographic element 123 is reflected by the fourth surface 132, crosstalk light is formed, which causes ghosting. Therefore, this application limits the incident angle of the crosstalk light to the fourth angle θ4 by the third holographic element 124, making the incident angle of the crosstalk light greater than the critical angle of total internal reflection in the optical waveguide. Due to the total internal reflection effect, the crosstalk light can propagate within the optical waveguide structure, thereby preventing the crosstalk light from escaping at the position of the main image, further reducing or even eliminating ghosting, further improving the display effect of the laminated glass 10, and further enhancing the user experience.

[0078] Figure 4 shows a schematic diagram of the laminated glass 10 viewed from inside the vehicle. The laminated glass 10 has a light-transmitting area 101 and a shielding area 102. The visible light transmittance of the light-transmitting area 101 is ≥70%, and the visible light transmittance of the shielding area 102 is ≤5%. The first holographic element 122 is disposed in the shielding area 102, and the second holographic element 123 and the third holographic element 124 are both disposed in the light-transmitting area 101. The second holographic element 123 is connected to the third holographic element 124.

[0079] The shielding area 102 is also commonly referred to as the black border area. Preferably, the shielding area 102 is a bottom shielding area located below the light-transmitting area 101. Optionally, the laminated glass 10 further includes a shielding layer located on the second surface 112 and / or the fourth surface 132, the shielding layer being disposed within the shielding area 102. The shielding layer can block ambient light, preventing unnecessary interference to the view, and can also improve the contrast between the displayed image and the displayed background, as well as achieve a higher color gamut, making the image display clearer. The material of the shielding layer is selected from at least one of dark ink, opaque polymer film, and dimming film.

[0080] Furthermore, as shown in Figure 4, a first holographic element 122, a second holographic element 123, and a third holographic element 124 constitute a holographic element group. The laminated glass 10 has a left-hand drive area 103 and a right-hand drive area 104 arranged along the length of the laminated glass 10. One holographic element group is disposed in the left-hand drive area 103, and the other holographic element group is disposed in the right-hand drive area 104. By distributing the two holographic element groups in the left-hand drive area 103 and the right-hand drive area 104 respectively, users in both the left-hand drive area 103 and the right-hand drive area 104 can clearly observe the display image formed by the projected light, reducing or even eliminating ghosting and improving the display effect of the laminated glass 10.

[0081] Along the height direction of the laminated glass 10, the height of the third holographic element 124 (as shown by H3 in Figure 4) is greater than the height of the second holographic element 123 (as shown by H2 in Figure 4), and the height of the second holographic element 123 (as shown by H2 in Figure 4) is greater than the height of the first holographic element 122 (as shown by H1 in Figure 4).

[0082] Since the projected light rays that illuminate the first holographic element 122 may not completely illuminate the center of the first holographic element 122, but may illuminate its edges, in order to ensure that the light reflected by the first holographic element 122 is completely received by the second holographic element 123, the height of the second holographic element 123 is made greater than the height of the first holographic element 122, which is beneficial for the second holographic element 123 to receive more projected light rays.

[0083] Furthermore, since the second holographic element 123 has the function of magnifying the image, in order to fully receive the light reflected back by the fourth surface 132, the height of the third holographic element 124 is made greater than the height of the second holographic element 123 to ensure that the third holographic element 124 receives more crosstalk light, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass 10.

[0084] The specific positions, heights, and widths of the first holographic element 122, the second holographic element 123, and the third holographic element 124 need to be determined based on the installation position of the projection device 20, the field of view (FOV), and the position of the eye box for different vehicle models, and are not limited here.

[0085] The first holographic element 122, the second holographic element 123, and the third holographic element 124 are flexible. They can be matched with a curved glass plate. Furthermore, the magnification and reduction of the image in the curved laminated glass 10 can be mutually canceled out by a single reflection between the third surface 131 and the fourth surface 132. The fourth surface 132 can be considered a convex mirror, and the third surface 131 a concave mirror, thus not affecting the display effect of the laminated glass 10.

[0086] Along the height direction of the laminated glass 10, there is a distance D between the first holographic element 122 and the second holographic element 123. The distance D satisfies the following formula: D = 2 × n × d × tanθ1; where n is a positive integer, d is the thickness of the second glass plate 13, and θ1 is the angle between the light reflected by the first holographic element 122 and the normal direction of the second glass plate 13. By limiting the distance between the first holographic element 122 and the second holographic element 123 by the above formula, it is ensured that the projected light reflected by the first holographic element 122 can be received by the second holographic element 123, so that the projected light exits the second glass plate 13 and enters the eye, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass 10.

[0087] The first holographic element 122, the second holographic element 123, and the third holographic element 124 are embedded in the polymer layer 121, and the thicknesses of the first holographic element 122, the second holographic element 123, the third holographic element 124, and the polymer layer 121 are equal. By limiting the thicknesses of the first holographic element 122, the second holographic element 123, the three holographic elements, and the polymer layer 121 to be equal, bulging of the laminated glass 10 can be avoided, and the reliability of the laminated glass 10 can be improved.

[0088] The absolute value of the difference between the refractive index of the first holographic element 122 and the refractive index of the polymer layer 121 is 0 to 0.01. Specific examples of the absolute value of the difference between the refractive index of the first holographic element 122 and the refractive index of the polymer layer 121 include 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, and 0.01.

[0089] And / or, the absolute value of the difference between the refractive index of the second holographic element 123 and the refractive index of the polymer layer 121 is 0 to 0.01. Specific examples of the absolute value of the difference between the refractive index of the second holographic element 123 and the refractive index of the polymer layer 121 include 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.01, etc.

[0090] And / or, the absolute value of the difference between the refractive index of the third holographic element 124 and the refractive index of the polymer layer 121 is 0 to 0.01. Specific examples of the absolute value of the difference between the refractive index of the third holographic element 124 and the refractive index of the polymer layer 121 include 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, or 0.01, etc.

[0091] By limiting the absolute value of the difference in refractive index between the polymer layer 121 and the first holographic element 122, the second holographic element 123, and the third holographic element 124, the polymer layer 121 can better cooperate with each holographic element, better limit the propagation of the projected light in a specific direction and range, thereby reducing or even eliminating ghosting and improving the display effect of the laminated glass 10.

[0092] This application, by setting a first holographic element, a second holographic element, and a third holographic element in conjunction with a polymer layer, can fundamentally solve the phenomenon of ghosting caused by the image being reflected twice on the first and fourth surfaces of the laminated glass. The image is reflected into the optical waveguide structure only through the first holographic element, and then propagated through the optical waveguide structure. Finally, the image is emitted through the second holographic element and enters the human eye. The remaining reflected light is further confined in the second glass plate by the third holographic element and emitted in a position that does not affect the main image. This significantly improves the display effect of the laminated glass and enhances the user experience.

[0093] This application provides a projection system, which includes a projection device and a laminated glass as described above. The projection device generates projection light, which is projected onto the fourth surface, and the laminated glass reflects the projection light to form a display image.

[0094] The wavelength of the projected light can be in the range of 380nm to 780nm. The projected light can contain at least 80% P-polarized light. The higher the proportion of P-polarized light in the projected light, the better it is for meeting the needs of drivers wearing sunglasses and the easier it is to eliminate visual ghosting in the displayed image.

[0095] This application provides a vehicle, the vehicle including a body and the projection system provided in this application above, the projection device of the projection system being installed inside the body, and the laminated glass of the projection system being installed at an opening in the body.

[0096] When laminated glass is installed in a vehicle, it is preferably used as the windshield. However, it is not limited to this; laminated glass can also be used as the rear windshield or side window glass, thus providing more display application scenarios for the vehicle.

[0097] The above provides a detailed description of the embodiments provided in this application. This document elucidates and explains the principles and implementation methods of this application. The above description is only intended to help understand the methods 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 laminated glass, characterized by, The laminated glass includes a first glass plate, an intermediate layer, and a second glass plate. The first glass plate has a first side and a second side, and the second glass plate has a third side and a fourth side. The intermediate layer connects the second side and the third side. The refractive index of the intermediate layer is less than that of the second glass plate, and the intermediate layer includes a coupling-in region and a coupling-out region spaced apart. The coupling-in region is used to receive the projected light rays incident from the fourth surface and change the propagation direction of the projected light rays. The coupling-out region is used to receive the projected light rays propagating in the second glass plate and change the propagation direction of the projected light rays. The projected light rays can enter the coupling area from the fourth surface. After being reflected by the coupling area, the projected light rays can be reflected back and forth between the intermediate layer and the fourth surface, so that the projected light rays can propagate within the second glass plate. Furthermore, the projected light rays propagating within the second glass plate can reach the coupling area. After being reflected by the coupling area, the projected light rays can pass through the fourth surface and exit the second glass plate.

2. Laminated glass according to claim 1, characterized in that The intermediate layer includes a polymer layer, a first holographic element disposed in the coupling region, and a second holographic element disposed in the coupling region. The polymer layer connects the second surface and the third surface. The refractive index of the polymer layer is less than the refractive index of the second glass plate. The first holographic element and the second holographic element are fixed to the polymer layer and are disposed facing the third surface. The first holographic element and the second holographic element are spaced apart.

3. Laminated glass according to claim 2, characterized in that The refractive index of the polymer layer is ≤1.52, or ≤1.40, or ≤1.30, or ≤1.

20.

4. The laminated glass according to claim 2, wherein The first holographic element is used to give the projected light a first angle θ1, where the first angle θ1 is the angle between the light reflected by the first holographic element and the normal direction of the second glass plate. The first angle θ1 satisfies the following formula: θ1≥arcsin(n2 / n1); where n1 is the refractive index of the second glass plate, and n2 is the maximum value of the refractive index of the polymer layer and the refractive index of air.

5. The laminated glass according to claim 2, wherein The projected light rays are generated by the projection device, and the incident direction of the projected light rays from the projection device to the fourth surface is perpendicular to the fourth surface.

6. The laminated glass according to claim 2, wherein The second holographic element is used to give the projected light a second angle θ2, which is the angle between the light reflected by the second holographic element and the normal direction of the second glass plate. The projected light also has a third angle θ3, which is the angle between the light emitted from the second glass plate and the normal direction of the second glass plate. The second angle θ2 and the third angle θ3 satisfy the following formula: sinθ2×n1=sinθ3×n3, and 1.52×sinθ2=sinθ3; where n1 is the refractive index of the second glass plate and n3 is the refractive index of air.

7. The laminated glass according to claim 2, wherein The area of ​​the first holographic element is greater than or equal to the area of ​​the projected light rays incident on the fourth surface; and / or, the area of ​​the second holographic element is greater than the area of ​​the first holographic element.

8. The laminated glass according to claim 2, wherein The intermediate layer also includes an auxiliary coupling region, which is located on the side of the coupling-out region away from the coupling-in region; the projected light rays are reflected sequentially by the coupling-out region and the fourth surface to form crosstalk light rays, and the auxiliary coupling region is used to receive the crosstalk light rays and change the propagation direction of the crosstalk light rays; The crosstalk light can be directed to the auxiliary coupling region, and after being reflected by the auxiliary coupling region, the crosstalk light can be reflected back and forth between the intermediate layer and the fourth surface, so that the crosstalk light can propagate within the second glass plate.

9. The laminated glass according to claim 8, wherein The intermediate layer further includes a third holographic element disposed in the auxiliary coupling region. The third holographic element is fixed to the polymer layer and is disposed facing the third surface. The third holographic element is disposed on the side of the second holographic element away from the first holographic element.

10. The laminated glass according to claim 9, wherein The third holographic element is used to give the crosstalk light a fourth angle θ4, which is the angle between the light reflected by the third holographic element and the normal direction of the second glass plate. The fourth angle θ4 satisfies the following formula: θ4≥arcsin(n2 / n1); where n1 is the refractive index of the second glass plate, and n2 is the maximum value between the refractive index of the polymer layer and the refractive index of air.

11. The laminated glass according to claim 9, wherein The laminated glass has a light-transmitting area and a shielding area, wherein the visible light transmittance of the light-transmitting area is ≥70%, and the visible light transmittance of the shielding area is ≤5%. The first holographic element is disposed in the shielding area, and the second holographic element and the third holographic element are both disposed in the light-transmitting area, with the second holographic element connected to the third holographic element.

12. The laminated glass of claim 9, wherein A first holographic element, a second holographic element, and a third holographic element constitute a holographic element group. The laminated glass has a left-hand drive area and a right-hand drive area arranged along the length direction of the laminated glass. One holographic element group is disposed in the left-hand drive area, and the other holographic element group is disposed in the right-hand drive area.

13. The laminated glass of claim 9, wherein Along the height direction of the laminated glass, the height of the third holographic element is greater than the height of the second holographic element, and the height of the second holographic element is greater than the height of the first holographic element.

14. The laminated glass of claim 9, wherein Along the height direction of the laminated glass, there is a distance D between the first holographic element and the second holographic element, and the distance D satisfies the following formula: D=2×n×d×tanθ1; where n is a positive integer, d is the thickness of the second glass plate, and θ1 is the angle between the light reflected by the first holographic element and the normal direction of the second glass plate.

15. The laminated glass of claim 9, wherein The first holographic element, the second holographic element, and the third holographic element are embedded in the polymer layer, and the thicknesses of the first holographic element, the second holographic element, the third holographic element, and the polymer layer are equal.

16. Laminated glass according to claim 15, characterized in that The thickness of the polymer layer is 0.20mm to 1mm, or 0.30mm to 0.90mm, or 0.40mm to 0.80mm.

17. The laminated glass of claim 9, wherein The absolute value of the difference between the refractive index of the first holographic element and the refractive index of the polymer layer is 0 to 0.01; And / or, the absolute value of the difference between the refractive index of the second holographic element and the refractive index of the polymer layer is 0 to 0.01; And / or, the absolute value of the difference between the refractive index of the third holographic element and the refractive index of the polymer layer is 0 to 0.

01.

18. The laminated glass of claim 11, wherein The laminated glass further includes a shielding layer disposed on the second surface and / or the fourth surface, the shielding layer being disposed within the shielding area.

19. A projection system, characterized by The projection system includes a projection device and a laminated glass as described in any one of claims 1-18, wherein the projection device generates projection light, the projection light is projected onto the fourth surface, and the laminated glass reflects the projection light to form a display image.

20. A vehicle characterized by comprising: The vehicle includes a body and the projection system of claim 19, wherein the projection device of the projection system is installed inside the body and the laminated glass of the projection system is installed at an opening in the body.

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