Projection display device and vehicle

Abstract

The invention provides a projection display device and a vehicle, two opposite sides of the projection display device are a first side and a second side respectively, and the projection display device comprises an inner light-transmitting layer, a display layer and an outer light-transmitting layer which are sequentially stacked in the direction from the first side to the second side; the display layer is configured to display a projection image received from the projection light source; the inner light-transmitting layer is configured to allow the projection image displayed on the display layer to be displayed towards the first side; the outer light-transmitting layer is configured to restrict the projection image displayed on the display layer from being displayed toward the second side. The projection display device provided by the invention can display the projection image towards one of the two opposite sides of the projection display device, and basically does not display the projection image towards the other side, so that a privacy protection function is achieved.

Description

Projection display device and vehicle Technical Field

[0001] The present application relates to the field of glass technology, and in particular to a projection display device and a vehicle. Background Art

[0002] As people become more and more dependent on vehicles, they are also putting forward more and more demands on vehicles. One of the demands is the desire for more space or planes as carriers for presenting information media, especially the desire to use projection light sources to project displays directly on the vehicle's glass.

[0003] Chinese patent application publication number CN113415051A discloses a glass and product with display function, including a laminated inner layer of glass, a display unit layer, and an outer layer of glass. The outer layer of glass is used to quantitatively control the transmittance of natural light, thereby suppressing the interference of sunlight on the image displayed by the display unit layer when external light is enhanced, thereby improving image contrast.

[0004] Summary of the Invention

[0005] The present application provides a projection display device and a vehicle, which can display a projection image toward one of two opposite sides of the projection display device, while basically not displaying the projection image toward the other side, thereby playing a privacy protection function.

[0006] In a first aspect, the present application provides a projection display device, wherein two opposite sides are respectively a first side and a second side, the projection display device includes an inner light-transmitting layer, a display layer, and an outer light-transmitting layer stacked in sequence in a direction from the first side toward the second side; the display layer is configured to display a projection image received from a projection light source; the inner light-transmitting layer is configured to allow the projection image displayed on the display layer to be displayed toward the first side; and the outer light-transmitting layer is configured to limit the projection image displayed on the display layer to be displayed toward the second side.

[0007] Optionally, the light projected by the projection light source is polarized light; the inner light-transmitting layer is configured to transmit the polarized light reflected by the display layer; and / or the outer light-transmitting layer is configured to absorb the polarized light transmitted by the display layer.

[0008] Optionally, the inner light-transmitting layer includes a first light-transmitting plate, the first light-transmitting plate has an incident surface facing the projection light source, and the first light-transmitting plate has a transmittance greater than or equal to 90% for the polarized light.

[0009] Optionally, the projection image displayed by the display layer has a first brightness, the projection image reflected by the incident surface of the first light-transmitting plate has a second brightness, and a ratio of the first brightness to the second brightness is greater than or equal to 4.5.

[0010] Optionally, the polarized light is P polarized light, and the P polarized light has an incident angle θ i Projected onto the incident surface, θ i Satisfying the formula θ i =tan -1 (n g / n i ), where n g is the refractive index of the first light-transmitting plate, n i is the refractive index of air.

[0011] Optionally, the inner light-transmitting layer further includes a second light-transmitting plate, and the second light-transmitting plate is arranged between the first light-transmitting plate and the display layer.

[0012] Optionally, the outer light-transmitting layer includes a polarizing layer, the polarizing layer has a light-transmitting axis, and the light-transmitting axis is orthogonal to the polarization direction of the polarized light projected onto the polarizing layer.

[0013] Optionally, the outer light-transmitting layer further includes a third light-transmitting plate, the polarizing layer is provided between the display layer and the third light-transmitting plate, and the third light-transmitting plate has a transmittance of less than or equal to 50% for natural light.

[0014] Optionally, the outer light-transmitting layer further includes a third light-transmitting plate, and the third light-transmitting plate is arranged between the display layer and the polarizing layer.

[0015] Optionally, the brightness of the projected image transmitted by the polarizing layer is a third brightness, and the third brightness is less than or equal to 5 nits.

[0016] In a second aspect, the present application further provides a vehicle comprising a vehicle window and a projection light source, wherein at least a portion of the vehicle window is the projection display device described in the embodiment of the first aspect; the projection light source is used to provide a projection image toward an inner light-transmitting layer of the projection display device.

[0017] The projection display device provided in the present application can display a projected image only toward one of its two opposite sides, and basically does not display a projected image toward the other side, thereby playing a privacy protection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some of the embodiments described in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. In the drawings:

[0019] FIG1 is a schematic diagram of a projection display device according to a first embodiment of the present application;

[0020] FIG2 is a schematic diagram of a projection display device according to a second embodiment of the present application;

[0021] FIG3 is a schematic diagram of the display module in FIG2 ;

[0022] FIG4 is a schematic diagram of a projection display device according to a third embodiment of the present application;

[0023] FIG5 is a schematic diagram of a projection display device according to a fourth embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0025] The term "including" and its variations used in this document indicate open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The terms "inside" and "outside" are only used to distinguish different objects and are not to be understood as limiting a specific direction. Unless otherwise stated, "multi-layer" means two or more layers.

[0026] The inventors of this application have discovered that images displayed on conventional glass with display functions tend to be visible on both sides of the glass, thus causing privacy leakage. For example, when the glass is used as a vehicle window, if a person inside the vehicle projects an image onto the glass using a projection light source, the projected image is visible not only to the person inside the vehicle but also to people outside the vehicle, which may be undesirable to the person inside the vehicle.

[0027] To solve the above problems, an embodiment of the first aspect of the present application provides a projection display device with a privacy protection function, which can be applied to display cabinets, building window curtain walls, automobile glass, ship glass, locomotive glass, human-computer interaction, electrical appliances, information kiosks, etc.

[0028] The projection display device comprises a first side and a second side on opposite sides, and includes an inner light-transmitting layer, a display layer, and an outer light-transmitting layer stacked in sequence from the first side toward the second side. The display layer is configured to display a projection image received from a projection light source. The inner light-transmitting layer is configured to allow the projection image displayed on the display layer to be displayed toward the first side. The outer light-transmitting layer is configured to restrict the projection image displayed on the display layer from being displayed toward the second side. In other words, the outer light-transmitting layer is configured to block or hinder the projection image displayed on the display layer from being displayed toward the second side, thereby preventing the projection image displayed on the display layer from being seen or clearly seen by a person located on the second side, thereby providing a privacy protection function.

[0029] Optionally, the inner light-transmitting layer may be a single-layer or multi-layer structure, and the outer light-transmitting layer may also be a single-layer or multi-layer structure.

[0030] Illustratively, the projection display device may be projection display glass, the inner light-transmitting layer may be a single-layer or multi-layer glass, and the outer light-transmitting layer may be a single-layer or multi-layer glass.

[0031] In some embodiments, the light projected by the projection light source is polarized light; the polarized light can be linearly polarized light, circularly polarized light, or higher-order polarized light; in some embodiments, the light projected by the projection light source is P-polarized light, which is a type of linearly polarized light. The beneficial effects of using P-polarized light in this embodiment include that when P-polarized light is incident at a specific angle, the reflectivity is essentially zero, thereby significantly reducing the reflection of light on the glass, thereby reducing the generation of image ghosting.

[0032] In this embodiment, the inner light-transmitting layer is configured to transmit the polarized light reflected by the display layer to allow the projected image displayed on the display layer to be displayed toward the first side; and / or, the outer light-transmitting layer is configured to absorb the polarized light transmitted by the display layer to limit the projected image displayed on the display layer to be displayed toward the second side.

[0033] Hereinafter, the principles of the present application will be described in detail in conjunction with exemplary embodiments with reference to the accompanying drawings.

[0034] FIG1 is a schematic diagram of a projection display device 100 according to a first embodiment of the present application.

[0035] As shown in FIG1 , the projection display device 100 has two opposing sides, namely a first side 101 and a second side 102. The projection display device 100 includes an inner light-transmitting layer 10, a display layer 20, and an outer light-transmitting layer 30, which are stacked in sequence from the first side 101 toward the second side 102. It will be understood that the display layer 20 is located between the inner light-transmitting layer 10 and the outer light-transmitting layer 30. A projection light source projects light toward the inner light-transmitting layer 10. In this embodiment, the light projected by the projection light source (not shown) is polarized light L1.

[0036] In this embodiment, as shown in Figure 1, the inner light-transmitting layer 10 includes a first light-transmitting plate 11, and the first light-transmitting plate 11 has an incident surface 111 facing the projection light source. The polarized light L1 projected by the projection light source is incident on the incident surface 111 of the first light-transmitting plate 11. At least part of the polarized light L1 passes through the first light-transmitting plate 11 to form a first transmitted light L2. The first transmitted light L2 is projected onto the display layer 20. The display layer 20 can reflect part of the first transmitted light L2 to form a first reflected light L3 (i.e., the projected image). The first light-transmitting plate 11 allows the first reflected light L3 to pass through, thereby allowing the projected image to be displayed toward the first side 101.

[0037] In this embodiment, as shown in FIG1 , the outer light-transmitting layer 30 includes a polarizing layer 31. A portion of the first transmitted light L2 passes through the display layer 20 to form the second transmitted light L4. The second transmitted light L4 is projected onto the polarizing layer 31. The polarizing layer 31 has a transmission axis that is orthogonal to the polarization direction of the second transmitted light L4. Therefore, substantially all or most of the second transmitted light L4 is absorbed by the polarizing layer 31 and cannot pass through the polarizing layer 31, thereby limiting the projected image from being displayed toward the second side 102. The dotted arrows in FIG1 indicate the polarization directions of the respective light rays.

[0038] In this embodiment, as shown in Figure 1, the ratio of the brightness of the projected image displayed by the display layer 20 to the brightness of the projected image reflected by the incident surface 111 of the first light-transmitting plate 11 is greater than or equal to 4.5, for example, the ratio is greater than or equal to 10, or greater than or equal to 100. Therefore, even if a small amount of polarized light is reflected by the incident surface 111 to form the second reflected light L5, the brightness of the projected image formed is much lower than the brightness of the projected image displayed by the display layer 20, thereby avoiding image ghosting on the incident surface 111 of the first light-transmitting plate 11.

[0039] For example, the polarized light L1 projected by the projection light source is P polarized light. As shown in FIG1 , the P polarized light is incident at an angle θ i Projected onto the incident surface 111 of the first light-transmitting plate 11, θ i Satisfying the formula θ i =tan -1 (n g / n i ),θ iAlso known as Brewster's angle, where n g is the refractive index of the first light-transmitting plate 11, n i is the refractive index of air. Theoretically, P polarized light with an incident angle θ i When projected onto the incident surface 111 of the first light-transmitting plate 11, the reflectivity of the incident surface 111 to P-polarized light is 0, thereby effectively suppressing the reflection of P-polarized light by the first light-transmitting plate 11, significantly reducing the brightness of the projected image reflected by the incident surface 111 of the first light-transmitting plate 11, and effectively avoiding image ghosting on the incident surface 111.

[0040] In this embodiment, the brightness of the projected image transmitted by the polarizing layer 31 is less than or equal to 5 nits, for example, less than or equal to 2 nits, or for example, less than or equal to 1 nit. Therefore, even if a small amount of the second transmitted light L4 passes through the polarizing layer 31 to form the third transmitted light L6, the projected image presented by the third transmitted light L6 is difficult to be seen or seen clearly by a person located on the second side 102 of the projection display device 100, thereby still preventing privacy leakage.

[0041] In this embodiment, the first light-transmitting plate 11 optionally has a transmittance of greater than or equal to 60% for the polarized light L1, for example, greater than or equal to 90%, and may be 95% or 98%. The high transmittance of the first light-transmitting plate 11 for the polarized light L1 can improve the brightness of the projected image displayed by the display layer 20. For example, the first light-transmitting plate 11 can be a single piece of glass or a double piece of glass, and the double piece of glass can have a hollow interlayer.

[0042] Illustratively, the polarizing layer 31 may be a flexible transparent substrate. For example, the polarizing layer 31 may be a linear polarizing filter, specifically a thin-film polarizer, a filter or thin-film layer having a linear dichroic material such as an anisotropic polymer layer, deformed metal nanoparticles, a nanoparticle linear thin-film polarizer, a metal polarizer, etc.

[0043] Among them, the thin film polarizer can be a multilayer optical film structure, and nanoscale or microscale molecules can be set in the multilayer structure. The wavelength and polarization response of the thin film polarizer can be controlled by controlling the rotation direction and thickness of the molecules.

[0044] The core polarizing film material in the dichroic film layer is polyvinyl alcohol (PVA). Its components are primarily light atoms such as carbon, hydrogen, and oxygen, resulting in high light transmittance and high ductility. After dyeing in a dyeing tank, the PVA film's surface becomes uniformly enriched with a layer of dichroic molecules, metal salts such as gold, silver, and iron, dye molecules, and polyethylene molecules. When an external force is applied to the PVA film, the molecular chains of the PVA film are distributed along the direction of the force, and the dichroic molecules are also distributed in an orderly manner, forming a polarizing layer 31 with uniform dichroic absorption properties, with its transmission axis perpendicular to the direction of stretching. Nanoparticle linear thin-film polarizers are made by embedding prolate ellipsoidal nanoparticles into sodium silicate glass.

[0045] In this embodiment, optionally, the polarizing layer 31 may be a combination of one or more of a linear polarization filter and a phase retarder, and the phase retarder may be a quarter-wave retarder and / or a half-wave retarder.

[0046] In this embodiment, as shown in FIG. 1 , the first light-transmitting plate 11 and the display layer 20 may be connected via a first adhesive layer 40 , and the polarizing layer 31 and the display layer 20 may be connected via a second adhesive layer 50 .

[0047] Optionally, the first light-transmitting plate 11, the first adhesive layer 40, the display layer 20 and the second adhesive layer 50 can be configured not to change the polarization state of the polarized light L1 projected by the projection light source, that is, the polarization states of the polarized light L1, the first transmitted light L2, the first reflected light L3 and the second transmitted light L4 are the same, for example, all are P-polarized light, which facilitates the configuration of the light-transmitting axis of the polarizing layer 31 according to the polarization state of the polarized light L1 without having to specifically consider changes in the polarization state.

[0048] However, the present application is not limited to this. One or more of the first light-transmitting plate 11, the first adhesive layer 40, the display layer 20 and the second adhesive layer 50 may also be configured to change the polarization state of the polarized light L1, that is, the polarization states of the polarized light L1, the first transmitted light L2, the first reflected light L3 and the second transmitted light L4 may be partially different or completely different. In this case, the light transmission axis of the polarizing layer 31 needs to be configured according to the polarization state of the second transmitted light L4 projected onto the polarizing layer 31.

[0049] In a feasible technical solution, the first bonding layer 40 and the second bonding layer 50 are made of a transparent bonding material, which may be polyvinyl butyral (PVB), polycarbonate, sound-insulating PVB, ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), ionomer, thermoplastic material and any combination thereof, or may be transparent optical adhesive (OCA), liquid transparent optical adhesive (LOCA) or optically transparent resin (OCR), etc.

[0050] Optionally, the transmittance of the first adhesive layer 40 and / or the second adhesive layer 50 to the polarized light L1 is greater than or equal to 85%, for example, greater than or equal to 90% or greater than or equal to 95%.

[0051] Optionally, the haze of the first adhesive layer 40 is less than or equal to 1%, for example, less than or equal to 0.4%.

[0052] Optionally, the thickness of the first adhesive layer 40 is 0.1 mm to 1 mm, for example, 0.38 mm or 0.76 mm, and the thickness of the second adhesive layer 50 is 0.1 mm to 1 mm, for example, 0.38 mm or 0.76 mm.

[0053] In another feasible technical solution, different from the previous technical solution, the second adhesive layer 50 is made of a dark adhesive material, which can be one or any combination of gray PVB film, light gray PVB film, blue PVB film, light blue PVB film, green PVB film, gray PVB film or brown PVB film.

[0054] Optionally, the transmittance of the second adhesive layer 50 to the polarized light L1 is less than or equal to 50%, for example, less than or equal to 5%, or less than or equal to 2%.

[0055] In this embodiment, the display layer 20 may have a display function in its entirety or in a partial area. The display layer 20 may be a combination of one or more of a light-emitting diode (LED), an organic light-emitting diode (OLED), a liquid crystal display (LCD), a projection display film, and electroluminescence. Among them, LED, LCD, and OLED use an external electric field to make the internal luminescent material emit light, thereby achieving a display effect. Projection display uses the principle that the projection display film has a unique high reflectivity for projector light to achieve a display effect. Electroluminescence uses an electric field to cause electrons to collide with luminescent centers to produce energy level transitions, ultimately emitting light. These display technologies have fast response speeds, low energy consumption, and wide viewing angles.

[0056] Optionally, the size of the display layer 20 may be equal to or smaller than the size of the first light-transmitting plate 11 , and the size of the polarizing layer 31 may be equal to or smaller than the size of the first light-transmitting plate 11 .

[0057] Figure 2 is a schematic diagram of a projection display device 100 according to a second embodiment of the present application. Unlike the first embodiment of the present application, the inner light-transmitting layer 10 further includes a second light-transmitting plate 12, which is arranged between the first light-transmitting plate 11 and the display layer 20. It can be understood that in the direction from the first side 101 to the second side 102, the first light-transmitting plate 11, the second light-transmitting plate 12, the display layer 20 and the polarizing layer 31 are stacked in sequence.

[0058] Optionally, the second light-transmitting plate 12 has a transmittance of greater than or equal to 90% for the polarized light L1, for example, 90%, 95%, or 98%. The high transmittance of the second light-transmitting plate 12 for the polarized light L1 can improve the brightness of the projected image displayed by the display layer 20. For example, the second light-transmitting plate 12 can be a transparent substrate, and its material can be a transparent material such as polyethylene terephthalate (PET), triacetate film (TAC), polymethyl methacrylate (PMMA), etc.

[0059] In this embodiment, as shown in FIG2 , the second light-transmitting plate 12 is connected to the display layer 20 via a third adhesive layer 60. The third adhesive layer 60 is made of a transparent adhesive material, and specifically may be polyvinyl butyral (PVB), polycarbonate, sound-insulating PVB, ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), ionomer, thermoplastic material, or a combination thereof, or may be a transparent optical adhesive (OCA), liquid optical adhesive (LOCA), or optically transparent resin (OCR).

[0060] Optionally, the transmittance of the third adhesive layer 60 to the polarized light L1 is greater than or equal to 85%, for example, may be 90% or 95%.

[0061] Optionally, the thickness of the third adhesive layer 60 is 0.1 mm to 1 mm, for example, 0.38 mm or 0.76 mm.

[0062] Optionally, the size of the display layer 20 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the second light-transmitting plate 12 , and the size of the polarizing layer 31 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the second light-transmitting plate 12 .

[0063] In this embodiment, as shown in FIG3 , the second light-transmitting plate 12 , the third adhesive layer 60 , the display layer 20 , the second adhesive layer 50 , and the polarizing layer 31 constitute a display module. The second light-transmitting plate 12 and the polarizing layer 31 serve as protective layers for the display layer 20 . The display module can be manufactured, installed, and disassembled as an integral component. For example, if the display layer 20 is damaged, only the display module can be replaced, thereby reducing the subsequent maintenance cost of the projection display device.

[0064] Figure 4 is a schematic diagram of a projection display device 100 according to a third embodiment of the present application. Unlike the first embodiment of the present application, the outer light-transmitting layer 30 further includes a third light-transmitting plate 32, and the polarizing layer 31 is arranged between the display layer 20 and the third light-transmitting plate 32. It can be understood that in the direction from the first side 101 to the second side 102, the first light-transmitting plate 11, the display layer 20, the polarizing layer 31 and the third light-transmitting plate 32 are stacked in sequence.

[0065] Optionally, the third light-transmitting plate 32 has a natural light transmittance of less than or equal to 50%, for example, 40%, 30%, 20%, or 10%, thereby reducing the natural light transmittance and suppressing interference of external light on the image displayed on the display layer 20. For example, the third light-transmitting plate 32 may be a single-piece glass or a double-piece glass, and the double-piece glass may have a hollow interlayer.

[0066] In this embodiment, as shown in FIG4 , the third light-transmitting plate 32 is connected to the display layer 20 via a fourth adhesive layer 70. The fourth adhesive layer 70 is made of a dark adhesive material, specifically, gray PVB film or EVA, light gray PVB film or EVA, blue PVB film or EVA, light blue PVB film or EVA, green PVB film or EVA, gray PVB film or EVA, or brown PVB film or EVA.

[0067] Optionally, the transmittance of the fourth adhesive layer 70 to the polarized light L1 is less than or equal to 50%, for example, less than or equal to 5%, or less than or equal to 2%.

[0068] Optionally, the fourth adhesive layer 70 has a thickness of 0.1 mm to 1 mm, for example, 0.38 mm or 0.76 mm.

[0069] Optionally, the size of the display layer 20 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the third light-transmitting plate 32 , and the size of the polarizing layer 31 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the third light-transmitting plate 32 .

[0070] In this embodiment, when preparing the projection display device 100, the polarizing layer 31 and the display layer 20 can be pre-compounded through the second adhesive layer 50 to form a composite component, and then the composite component is compounded with the first light-transmitting plate 11 and the third light-transmitting plate 32 by hot pressing to obtain the projection display device 100.

[0071] Figure 5 is a schematic diagram of a projection display device 100 according to a fourth embodiment of the present application. Unlike the third embodiment of the present application, the third light-transmitting plate 32 is arranged between the display layer 20 and the polarizing layer 31. It can be understood that in the direction from the first side 101 to the second side 102, the first light-transmitting plate 11, the display layer 20, the third light-transmitting plate 32 and the polarizing layer 31 are stacked in sequence.

[0072] In this embodiment, the third light-transmitting plate 32 has a transmittance of less than or equal to 98% for the polarized light L1 , such as less than or equal to 50%, such as less than or equal to 30%, such as less than or equal to 10%.

[0073] 5 , the third light-transmitting plate 32 is connected to the display layer 20 via a fourth adhesive layer 70. The material, light transmittance, and thickness of the fourth adhesive layer 70 can be set with reference to the third embodiment of the present application, and thus will not be described in detail.

[0074] Optionally, the size of the display layer 20 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the third light-transmitting plate 32 , and the size of the polarizing layer 31 may be equal to or smaller than the size of the first light-transmitting plate 11 and / or the third light-transmitting plate 32 .

[0075] The second embodiment of the present application provides a vehicle, including a vehicle window and a projection light source for providing a projected image. At least a portion of the vehicle window comprises the projection display device 100 provided in the first embodiment of the present application. The inner light-transmitting layer 10 of the projection display device 100 faces the interior of the vehicle, serving as the inner glass of the vehicle window. Alternatively, the inner light-transmitting layer 10 of the projection display device 100 faces the exterior of the vehicle, serving as the outer glass of the vehicle window.

[0076] In some embodiments, the projection light source may include a light-emitting diode (LED), a liquid crystal display (LCD), a digital light processing (DLP) projection light source, or any other image projection light source. The projection light source may be a fixed light source, such as a fixed light source attached to a vehicle body panel, or a mobile light source, such as a mobile phone. The projection light source may be located inside or outside the vehicle.

[0077] In some embodiments, the inner light-transmitting layer 10 of the projection display device 100 faces the interior of the vehicle, and the projection light source is arranged inside the vehicle to project the projection image toward the inner light-transmitting layer 10. Therefore, the projection image can be seen by people inside the vehicle, but basically cannot be seen by people outside the vehicle.

[0078] In other embodiments, the inner light-transmitting layer 10 of the projection display device 100 faces the outside of the vehicle, and the projection light source is arranged outside the vehicle to project the projection image toward the inner light-transmitting layer 10. Therefore, the projection image can be seen by people outside the vehicle, but basically cannot be seen by people inside the vehicle.

[0079] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A projection display device, wherein two opposite sides thereof are respectively a first side and a second side, and the projection display device comprises an inner light-transmitting layer, a display layer and an outer light-transmitting layer which are sequentially stacked in a direction from the first side to the second side; The display layer is configured to display a projection image received from a projection light source; The inner light-transmitting layer is configured to allow the projected image displayed on the display layer to be displayed toward the first side; The outer light-transmitting layer is configured to restrict the projection image displayed on the display layer from being displayed toward the second side.

2. The projection display device according to claim 1, in, The light projected by the projection light source is polarized light; The inner light-transmitting layer is configured to transmit the polarized light reflected by the display layer; and / or the outer light-transmitting layer is configured to absorb the polarized light transmitted by the display layer.

3. The projection display device according to claim 2, in, The inner light-transmitting layer includes a first light-transmitting plate, the first light-transmitting plate has an incident surface facing the projection light source, and the first light-transmitting plate has a transmittance greater than or equal to 90% for the polarized light.

4. The projection display device according to claim 3, in, The projection image displayed by the display layer has a first brightness, the projection image reflected by the incident surface of the first light-transmitting plate has a second brightness, and a ratio of the first brightness to the second brightness is greater than or equal to 4.

5.

5. The projection display device according to claim 3, in, The polarized light is P polarized light, and the P polarized light has an incident angle θ i Projected onto the incident surface, θ i Satisfies the following formula: θ i =tan -1 (n g / n i ) Among them, n g is the refractive index of the first light-transmitting plate, n i is the refractive index of air.

6. The projection display device according to claim 3, in, The inner light-transmitting layer further includes a second light-transmitting plate, and the second light-transmitting plate is arranged between the first light-transmitting plate and the display layer.

7. The projection display device according to any one of claims 2 to 6, in, The outer light-transmitting layer includes a polarizing layer. The polarizing layer has a light-transmitting axis. The light-transmitting axis is orthogonal to a polarization direction of the polarized light projected onto the polarizing layer.

8. The projection display device according to claim 7, in, The outer light-transmitting layer further includes a third light-transmitting plate, the polarizing layer is arranged between the display layer and the third light-transmitting plate, and the third light-transmitting plate has a transmittance of less than or equal to 50% for natural light.

9. The projection display device according to claim 7, in, The outer light-transmitting layer further includes a third light-transmitting plate, and the third light-transmitting plate is arranged between the display layer and the polarizing layer.

10. The projection display device according to claim 7, in, The brightness of the projected image transmitted by the polarizing layer is a third brightness, and the third brightness is less than or equal to 5 nits.

11. A vehicle, include: A vehicle window, at least a portion of which is a projection display device according to any one of claims 1 to 10; as well as The projection light source is used to provide a projection image toward the inner light-transmitting layer of the projection display device.

Images