Augmented reality head-up display device, vehicle, and method of manufacturing a reflective unit

Abstract

The application relates to an augmented reality head-up display device, which comprises an image unit, a light waveguide unit and a reflection unit, the reflection unit comprises a transparent piece with a reflection function and a multi-spectrum reflection layer arranged on the transparent piece, the transparent piece comprises at least two layers of transparent plates arranged in a stack, the multi-spectrum reflection layer is arranged on a first transparent plate close to the light waveguide unit, the multi-spectrum reflection layer has high reflectivity with a certain bandwidth for red, green and blue multi-band light, so that less image light transmits through the first transparent plate to other transparent plates, thereby effectively eliminating ghosting phenomenon and improving the quality and efficiency of the display image, meanwhile, the multi-spectrum reflection layer highly reflects a relatively narrow bandwidth at a red, green and blue main band, part of the light is transmitted, and all light is not reflected, thereby avoiding mirror effect and improving safety performance.

Description

Technical Field

[0001] This invention relates to an augmented reality head-up display device, a vehicle, and a method for manufacturing a reflective unit, belonging to the field of display device technology. Background Technology

[0002] A head-up display (HUD) functions as a "projector" for automotive information. This technology projects vehicle-related information onto the driver's line of sight, reducing the frequency of looking down at the instrument panel or center console screen while driving. A traditional HUD is an opto-electro-mechanical coupling device, mainly composed of a main control PCB board, a light source, a display medium, optical lenses, and a DC motor. The information is reflected multiple times by the display light source through a mirror structure onto a transparent medium (display screen or windshield), creating a virtual image that appears to float in front of the eyes. The use of HUDs greatly improves driving comfort and safety, and the global HUD installation volume is expected to reach 15 million units by 2025.

[0003] Based on product form, the mainstream HUDs are currently divided into combined type (C-HUD) and windshield type (W-HUD). Technically, C-HUD has a simple optical structure and is relatively easy to design, but its display size and projection distance are limited, and it may cause secondary injury to the driver in the event of a vehicle collision. W-HUD has a more integrated display effect, but its optical structure is complex, its design and layout are more difficult, it occupies a large volume, and its optical principle requires the use of a complex windshield surface, which undoubtedly increases the difficulty of manufacturing and mass production.

[0004] In recent years, augmented reality head-up displays (AR-HUDs) based on optical waveguides have emerged, overlaying digital images onto the real environment outside the vehicle, giving drivers an augmented reality visual experience. They can be used for AR navigation, adaptive cruise control, lane departure warning, and more.

[0005] Compared to the currently mainstream C-HUD and W-HUD, AR-HUD features smaller size, longer projection distance, wider field of view, and greater versatility. In existing technologies, because windshields generally employ a double-layer structure, light passing through the windshield undergoes secondary reflection, creating visual ghosting and significantly increasing visual discomfort. Summary of the Invention

[0006] The purpose of this invention is to provide an augmented reality head-up display device that can effectively eliminate ghosting and improve the quality and efficiency of displayed images.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an augmented reality head-up display device, comprising an image unit, an optical waveguide unit, and a reflection unit. The image unit generates image light rays and guides the image light rays to be incident on the surface of the optical waveguide unit. The optical waveguide unit transmits the image light rays and emits them toward the reflection unit. The reflection unit reflects the image light rays to the human eye and generates a virtual image. The reflection unit includes a transparent component with a reflective function and a multispectral reflective layer disposed on the transparent component. The transparent component includes at least two layers of transparent plates stacked together. The multispectral reflective layer is disposed on a first transparent plate close to the optical waveguide unit.

[0008] Furthermore, the multispectral reflective layer includes at least one low-refractive-index layer and at least one high-refractive-index layer. The multispectral reflective layer can be expressed as (LH)^m, where L is the low-refractive-index layer, H is the high-refractive-index layer, and m is the number of stacking periods. The refractive index of the high-refractive-index layer and the refractive index of the low-refractive-index layer differ by at least 0.1.

[0009] Furthermore, the thickness range of the low refractive index layer is 0–300 nm; the thickness range of the high refractive index layer is 0–100 nm; the number of stacking periods m is 2–50; and the thickness range of the first low refractive index layer disposed near the first transparent plate is greater than 0.

[0010] Furthermore, the refractive index of the low-refractive-index layer ranges from 1.3 to 1.78; and the refractive index of the high-refractive-index layer ranges from 1.8 to 2.9.

[0011] Furthermore, the material of the low refractive index layer is any one or more of silicon oxide, aluminum oxide, and magnesium fluoride; the material of the high refractive index layer is any one or more of titanium oxide, iron oxide, niobium oxide, tantalum oxide, zirconium oxide, chromium oxide, cerium oxide, and cobalt oxide.

[0012] Furthermore, a matching layer is provided between the multispectral reflective layer and the first transparent plate, and the refractive index of the matching layer is 2.0 to 2.9.

[0013] Furthermore, the multispectral reflective layer includes a substrate layer and a microstructure layer formed on the substrate layer. The microstructure layer includes a plurality of repeating microstructures, each microstructure including at least three microstructure units. Each microstructure unit has a different width and includes a protrusion and a groove adjacent to the protrusion. The width of the protrusion ranges from 100 to 400 nm, the height of the protrusion ranges from 50 to 300 nm, and the width of the groove ranges from 50 to 300 nm.

[0014] Furthermore, the refractive index of the base layer and the microstructure layer is 1.4 to 1.7, and the material of the base layer and the microstructure layer is any one of flexible acrylic, resin, and plastic.

[0015] Furthermore, the transparent component is a double-layered windshield.

[0016] Furthermore, the optical waveguide unit includes at least one optical waveguide, a first light-shielding layer disposed on one side of the optical waveguide, and a second light-shielding layer disposed on the other side of the optical waveguide. The first light-shielding layer is used to absorb light transmitted from the optical waveguide, and the second light-shielding layer is used to absorb light transmitted and / or reflected from the optical waveguide, as well as sunlight transmitted from the outside.

[0017] The present invention also provides a method for preparing the reflective unit as described above, the method comprising:

[0018] S11: Provide a transfer layer, on which a matching layer is made;

[0019] S12: Prepare a low refractive index layer on the matching layer, and then prepare multiple low refractive index layers or high refractive index layers to form a multispectral reflective layer;

[0020] S13: The transfer layer is attached to the first transparent plate to obtain the reflective unit.

[0021] The present invention also provides a method for preparing the reflective unit as described above, the method comprising:

[0022] S21: Provide a substrate layer, and spin-coat photoresist on the substrate layer;

[0023] S22: Fabricate a pattern of a microstructure layer on the photoresist;

[0024] S23: Transfer the pattern of the microstructure layer to the base layer to form a multispectral reflective layer;

[0025] S24: Provides a transfer layer to transfer the multispectral reflective layer to the transfer layer;

[0026] S25: The transfer layer is attached to the first transparent plate to obtain the reflective unit.

[0027] The present invention also provides a vehicle including the augmented reality head-up display device as described above.

[0028] The beneficial effects of the present invention are as follows: The augmented reality head-up display device of the present invention has a multispectral reflective layer with a certain bandwidth for red, green and blue multi-band light on the first transparent plate near the optical waveguide unit, which is used to reflect image light, so that less image light passes through the first light-transmitting plate and is incident on other transparent plates, thereby effectively eliminating ghosting and improving the quality and efficiency of the displayed image.

[0029] Meanwhile, the multispectral reflective layer provides high reflectivity in the narrow bandwidth of the red, green, and blue main wavelengths, allowing some light to pass through while preventing all light from being reflected, thus avoiding the mirror effect and improving safety performance.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the optical path of an augmented reality head-up display device according to an embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the optical path of the reflective unit in an augmented reality head-up display device in the prior art;

[0033] Figure 3 for Figure 2 The diagram shows the optical path through which the reflective unit creates the ghosting effect.

[0034] Figure 4 for Figure 1 The diagram shows the optical path of a portion of the augmented reality head-up display device.

[0035] Figure 5 for Figure 1 The diagram shows the optical path for ghosting elimination in a portion of an augmented reality head-up display.

[0036] Figure 6 The simulation diagram of the reflection efficiency versus wavelength effect of the multispectral reflective layer obtained in Example 1 is shown.

[0037] Figure 7 for Figure 1 A schematic diagram of a multispectral reflective layer;

[0038] Figure 8 The image shows a simulation of the reflection efficiency versus wavelength effect of the multispectral reflective layer obtained in Example 2. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the referred mechanism or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] Please see Figure 1 An embodiment of this application shows an augmented reality head-up display device, which includes an image unit 1, an optical waveguide unit 2, and a reflection unit 3. The image unit 1 generates image light rays and guides the image light rays to be incident on the surface of the optical waveguide unit 2. The optical waveguide unit 2 conducts the image light rays, while increasing the exit pupil expansion, and emits them toward the reflection unit 3. The image light rays emitted from the optical waveguide unit 2 illuminate the reflection unit 3, and the reflection unit 3 reflects the image light rays illuminating it to the human eye and generates a virtual image.

[0043] The head-up display principle of the augmented reality head-up display device is as follows: the image unit 1 emits image light with a certain field of view, the image light enters the optical waveguide unit 2, and after the exit pupil of the optical waveguide unit 2 is expanded, it is emitted. The emitted image light is reflected to the human eye by the reflection unit 3 at a certain reflection angle, and the human eye can see a virtual image at a certain projection distance through the reflection unit 3.

[0044] The optical waveguide unit 2 includes at least one layer of optical waveguide 21, which can be one layer, two layers, or three layers of optical waveguide 21, etc. In this embodiment, the optical waveguide unit 2 includes three layers of stacked optical waveguide 21. The number of layers of optical waveguide 21 is not specifically limited here and can be set according to actual needs.

[0045] The surface of the optical waveguide 21 is provided with an insertion region (not shown) and an exit region (not shown). The insertion region is configured to couple incident image light rays into the optical waveguide 21 and conduct them along the optical waveguide 21 to the exit region. The exit region is configured to emit the image light rays from the optical waveguide 21. The image light rays, after passing through the insertion region, undergo diffraction and total internal reflection within the optical waveguide 21. The diffracted and totally reflected image light rays are conducted multiple times within the optical waveguide 21, filling the entire exit region and exiting there, thus achieving exit pupil expansion. The optical waveguide 21 can continuously conduct the inserted light rays in a specific direction under the condition of total internal reflection. The transmittance of the optical waveguide 21 is greater than 80%. The optical waveguide 21 can be made of glass, resin, or a material with a transmittance greater than 80% under visible light; these are not listed here. The thickness of the optical waveguide 21 is less than 2 mm. The specific thickness of the optical waveguide 21 is not specifically limited here and can be set according to actual needs.

[0046] The coupling-in and coupling-out regions are structural units with diffraction properties. Essentially, they are nanostructures with refractive index gradients that enable light diffraction and transmission. Specifically, both the coupling-in and coupling-out regions are periodic grating structures, such as nanoscale relief gratings or volume holographic gratings. These periodic grating structures can be directly fabricated on the optical waveguide 21 or pre-fabricated on a thin film, which is then bonded to the optical waveguide 21. The bottom of the grating structures forming the coupling-in and coupling-out regions can be located on the surface of the optical waveguide 21 or inside the optical waveguide 21.

[0047] Both the coupling-in region and the coupling-out region can be rectangular, and the coupling-in region can also be circular or other shapes, depending on the requirements. The coupling-in region and the coupling-out region are arranged along the same axis on both sides of the same surface or on both sides of different surfaces of the optical waveguide 21. In this embodiment, the coupling-in region and the coupling-out region are located on the same surface of the optical waveguide 21 and there is a gap between them. The grating structure can be fabricated using holographic interference technology, photolithography technology, or nanoimprint technology, and can be freely selected according to actual needs.

[0048] The coupling region is preferably an inclined relief grating. Image light rays are incident at the coupling region and coupled into the optical waveguide 21 through a diffraction process. The inclined diffraction grating is wavelength selective, avoiding dispersion and exhibiting high diffraction efficiency for a specific wavelength band. The period and orientation of the grating structure in the coupling region are consistent with those in the coupling region; it can be a positive grating or an inclined grating.

[0049] By designing parameters such as the period, depth, duty cycle, and tilt angle of the grating structure, wavelength selectivity can be achieved by efficiently selecting light of a specific wavelength or band. For example, green image light can be coupled and then bent and propagated within the waveguide, while blue and red image light are not affected, achieving single-channel light diffraction. Alternatively, high-efficiency selection can be achieved for blue and red light bands, realizing dual-channel light diffraction. The single-channel diffraction waveguide 21 only propagates the light of one color image, while other colors of image light pass through the waveguide 21, ensuring that the light rays do not interfere with each other.

[0050] Furthermore, the surface of the optical waveguide 21 may also be provided with a transition region (not shown). The transition region is used to change the propagation direction of image light within the optical waveguide 21. When image light is incident on the coupling region, the image light is totally reflected within the optical waveguide 21 to the transition region. The transition region changes the propagation direction of the image light, causing the image light with the changed direction to be totally reflected to the coupling region. This can effectively expand the pupil of the output image, thereby widening the viewing angle and better meeting user needs.

[0051] The optical waveguide unit 2 also includes a first light-shielding layer 22 disposed on one side of the optical waveguide 21 and a second light-shielding layer 23 disposed on the other side of the optical waveguide 21. The first light-shielding layer 22 is used to absorb light transmitted from the optical waveguide 21, and the second light-shielding layer 23 is used to absorb light transmitted and / or reflected from the optical waveguide 21 as well as sunlight transmitted from the outside.

[0052] There are gaps between the first light-shielding layer 22 and the second light-shielding layer 23 and the optical waveguide 21, so as to absorb the light transmitted or reflected from the optical waveguide 21 and avoid absorbing the light inside the optical waveguide 21. The specific gap is not specifically limited here and can be set according to actual needs.

[0053] The first light-shielding layer 22 and the second light-shielding layer 23 have an absorption rate of more than 60% in the visible light band. That is, the first light-shielding layer 22 and the second light-shielding layer 23 can be made of a structure or a material with an absorption rate of more than 60% in the visible light band. Specific materials and structures are not listed here, and can be selected according to actual needs.

[0054] If the optical waveguide unit 2 does not have a first light-shielding layer 22, even after passing through multiple optical waveguides 21, some image light will still exit through the optical waveguide 21. Specifically, regardless of whether the image light is incident perpendicularly or obliquely into the coupling region, only a portion of the light will diffract and propagate within the optical waveguide 21; the 0th order diffracted light will all exit through the optical waveguide 21. This portion of image light will be reflected or diffusely reflected by any surface with reflective properties, and the reflected or diffusely reflected light will re-enter the optical waveguide 21, introducing stray light and affecting image quality. However, if the optical waveguide unit 2 has a first light-shielding layer 22, the first light-shielding layer 22 will absorb the image light exiting through the optical waveguide 21, preventing it from re-entering the optical waveguide 21 after reflection or diffuse reflection, thereby reducing interference and improving image quality.

[0055] The projection area of ​​the first light-shielding layer 22 on the surface of the optical waveguide 21 covers the projection area of ​​the coupled region on the surface of the optical waveguide 21, and the projection areas of the first light-shielding layer 22 and the coupled region on the surface of the optical waveguide 21 are separated, thereby maximizing the absorption of light transmitted from the surface of the optical waveguide 21. That is, the maximum area covered by the projection area of ​​the first light-shielding layer 22 on the surface of the optical waveguide 21 is the area excluding the projection area of ​​the coupled region on the surface of the optical waveguide 21, and the minimum area is the projection area of ​​the coupled region on the surface of the optical waveguide 21.

[0056] If the optical waveguide unit 2 does not have a second light-shielding layer 23, the image light transmitted in the optical waveguide 21, even after passing through multiple optical waveguides 21, will be transmitted through the coupling region on the side opposite to the reflection unit 3. Additionally, external sunlight, after passing through the reflection unit 3, will also enter the optical waveguide 21 and be transmitted through the coupling region 213 on the side opposite to the reflection unit 3. In other words, sunlight will also flow back and conduct in reverse within the optical waveguide 21, causing overheating and damage to critical components. Simultaneously, when image light enters the optical waveguide 21, some light will be reflected by the surface of the optical waveguide 21. This light will be reflected or diffusely reflected by any surface with reflective properties, and after reflection or diffuse reflection, it will re-enter the optical waveguide 21, introducing stray light and affecting image quality. However, if the optical waveguide unit 2 has a second light-shielding layer 23, this layer absorbs this light, preventing it from re-entering the optical waveguide 21 or conducting in reverse after reflection or diffuse reflection, thereby reducing the impact and improving image quality.

[0057] The projection area of ​​the second light-shielding layer 23 on the surface of the optical waveguide 21 covers the projection area of ​​the coupling region on the surface of the optical waveguide 21, and the projection area of ​​the second light-shielding layer 23 on the surface of the optical waveguide 21 and the projection area of ​​the image unit 1 on the surface of the optical waveguide 21 are separated, thereby maximizing the absorption of light transmitted and / or reflected from the surface of the optical waveguide 21. That is, the maximum range covered by the projection area of ​​the second light-shielding layer 23 on the surface of the optical waveguide 21 is the area excluding the projection area of ​​the image unit 1 on the surface of the optical waveguide 21, and the minimum range is the projection area of ​​the coupling region on the surface of the optical waveguide 21.

[0058] By setting the dimensions of the grating structures in the coupling-in and coupling-out regions, the distance between them, the specific structure of the grating, the thickness of the optical waveguide 21, and the position and dimensions of the first light-shielding layer 22 and the second light-shielding layer 23, image light can be coupled in through diffraction in the coupling-in region, diffracted by the optical waveguide 21 and transmitted to the coupling-out region. The light transmitted and reflected from the surface of the optical waveguide 21 is absorbed by the first light-shielding layer 22 or the second light-shielding layer 23, and emitted from the coupling-out region to illuminate the reflection unit 3. The light is reflected by the reflection unit 3 to the human eye, forming a virtual image in front of the human eye, thus improving the imaging quality.

[0059] The reflective unit 3 includes a transparent element 31 with reflective function and a multispectral reflective layer 32 disposed on the transparent element 31. The transparent element 31 includes at least two stacked transparent plates, that is, when image light shines on the transparent element 31, the transparent element 31 reflects the image light at least twice. The transparent element 31 includes a first transparent plate 311 disposed near the optical waveguide unit 2 and a second transparent plate 312 stacked with the first transparent plate 311. The first transparent plate 311 and the second transparent plate 312 can be curved or planar structures, which are not specifically limited here. In this embodiment, the transparent element 31 is a double-layered windshield, and both the first transparent plate 311 and the second transparent plate 312 are windshields, but it is not limited to this. The transparent element 31 can also have other structures, which are not listed here.

[0060] like Figure 6 and Figure 8 As shown, the multispectral reflective layer 32 highly reflects the narrow bandwidth in the red, green and blue main bands, thereby allowing most of the wider bandwidth light to pass through and avoiding all light from being reflected, thus producing a mirror effect and affecting safety.

[0061] Please see Figure 2 In existing AR-HUD solutions, image light emitted from the optical waveguide unit is incident on the reflection unit 03, which is the windshield 03. The windshield has high transmittance and low reflectivity. Therefore, most of the image light will pass through the windshield and be emitted, while less image light will be reflected by the windshield and received by the human eye, thus greatly reducing the light utilization efficiency.

[0062] Please see Figure 3 The windshield 03 is generally a double-layered windshield with two front surfaces. Image light emitted from the optical waveguide unit enters the double-layered windshield and is first reflected by the first front surface 031. Some of the light passes through the first front surface 031 and enters the second front surface 032, where it is reflected again. The light from both reflections is received by the human eye, thus creating a ghosting effect in the distance.

[0063] Please see Figure 4 The multispectral reflective layer 32 helps to improve display efficiency. The image light emitted from the optical waveguide unit 2 enters the reflective unit 3 and is reflected by the multispectral reflective layer 32 on the surface of the reflective unit 3. Because the multispectral reflective layer 32 has high reflection efficiency, most of the light is reflected to the human eye, which significantly improves the light utilization efficiency.

[0064] Please see Figure 5 A multispectral reflective layer 32 is disposed on the first transparent plate 311 near the optical waveguide unit 2, so that most of the image light is reflected on the first transparent plate 311, and less image light passes through the first transparent plate and enters the second transparent plate 312. That is, it enhances the first reflection of the transparent element 31 and weakens or even eliminates the second reflection of the transparent element 31. Therefore, the main image light received by the human eye is only the light reflected by the first transparent plate, and the light reflected by the second transparent plate can be ignored, thereby effectively eliminating the ghosting phenomenon. The specific reflection efficiency of the multispectral reflective layer 32 depends on the acceptable range of the ratio of the reflection efficiencies of the first transparent plate and the second transparent plate.

[0065] The multispectral reflective layer comprises at least one low-refractive-index layer and at least one high-refractive-index layer, which can be expressed as (LH)^m, where L is the low-refractive-index layer, H is the high-refractive-index layer, and m is the number of stacking periods.

[0066] The thickness of the low-refractive-index layer ranges from 0 to 300 nm, the thickness of the high-refractive-index layer ranges from 0 to 100 nm, and the number of stacking periods m ranges from 2 to 50. The thickness of the first low-refractive-index layer located near the first transparent plate is greater than 0; that is, the first refractive-index layer located near the first transparent plate in the multispectral reflective layer is a low-refractive-index layer.

[0067] The refractive index of the low-refractive-index layer ranges from 1.3 to 1.78. The refractive index of the high-refractive-index layer ranges from 1.8 to 2.9, and the difference between the refractive indices of the high-refractive-index layer and the low-refractive-index layer is at least 0.1.

[0068] The low-refractive-index layer is made of one or more of silicon oxide, aluminum oxide, and magnesium fluoride; the high-refractive-index layer is made of one or more of titanium oxide, iron oxide, niobium oxide, tantalum oxide, zirconium oxide, chromium oxide, cerium oxide, and cobalt oxide. Other materials may also be used for the low-refractive-index and high-refractive-index layers, but these will not be listed here.

[0069] In addition, a matching layer is disposed between the multispectral reflective layer and the first transparent plate, and the refractive index of the matching layer is 2.0 to 2.9. The material of the matching layer is usually silicon dioxide.

[0070] The multispectral reflective layer has a reflectivity of 70%–100% for light in the 440–460 nm wavelength band, 70%–100% for light in the 515–535 nm wavelength band, and 70%–100% for light in the 610–630 nm wavelength band.

[0071] The above-described reflective unit will be further explained below with reference to specific embodiments.

[0072] Example 1

[0073] The reflective unit can be expressed as: SM|(LH)^m|, where S is the transparent element, i.e., the windshield, M is the matching layer, which is a high refractive index material TiO2, L is a low refractive index material SiO2, H is a high refractive index material TiO2, and m is the number of stacking periods. The thickness of each layer is shown in Table 1 below.

[0074] Table 1. Materials and thicknesses of the matching layer, low-refractive-index layer, and high-refractive-index layer in Example 1.

[0075] layer Matching layer 1 2 3 4 5 6 7 Material <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[SiO2]]> thickness nm 93.7 270.94 22.06 0 128.06 102.62 0 85 layer 8 9 10 11 12 13 14 Material <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> thickness nm 77.25 159.25 0 168.21 61.631 23.67 84.91

[0076] Please see Figure 6 According to the reflection efficiency curve of the multispectral reflective layer obtained in this embodiment, the reflectivity of light in the visible light band is greater than 70% for light in the 430-460nm band, greater than 70% for light in the 520-530nm band, and greater than 70% for light in the 580-635nm band.

[0077] This application also provides a method for preparing the reflective unit shown above, the method comprising:

[0078] S11: Provides a transfer layer, on which a matching layer is created;

[0079] S12: Prepare a low refractive index layer on the matching layer, and then prepare multiple low refractive index layers or high refractive index layers to form a multispectral reflective layer;

[0080] S13: The transfer layer is attached to the first transparent plate to obtain the reflective unit.

[0081] The transfer layer serves as a carrier during the fabrication of the multispectral reflective layer and is used to transfer the multispectral reflective layer to the windshield. The materials of the transfer layer include flexible acrylic, resin, and plastic, which will not be listed here.

[0082] Matching layers, low-refractive-index layers, and high-refractive-index layers can be prepared by physical vapor deposition (PVD), but are not limited to this and can also be prepared by other methods.

[0083] The specific thickness, materials used, and stacking method of the low-refractive-index layer and the high-refractive-index layer can be set according to actual needs.

[0084] In addition, the multispectral reflective layer can also be other structures, including a base layer and a microstructure layer formed on the base layer.

[0085] The microstructure layer comprises several repeating microstructures, each microstructure consisting of at least three microstructure units, each with a different width. Each microstructure unit includes a protrusion and a groove adjacent to the protrusion. The width of the protrusion ranges from 100 to 400 nm, the height of the protrusion ranges from 50 to 300 nm, and the width of the groove ranges from 50 to 300 nm.

[0086] The refractive index of the substrate layer and the microstructure layer is 1.4–1.7. The material of the substrate layer and the microstructure layer can be any of flexible acrylic, resin, or plastic, but is not limited to these, and will not be listed here. Furthermore, the substrate layer has a transmittance of more than 80% in the visible light band.

[0087] The above-described reflective unit will be further explained below with reference to specific embodiments.

[0088] Example 2

[0089] Please see Figure 7 The base layer 321 of the multispectral reflective layer 32 is made of silicon oxide. The microstructure in the microstructure layer includes three microstructure units: a first microstructure unit, a second microstructure unit, and a third microstructure unit. The first microstructure unit includes a first protrusion 322 and a first groove 323; the second microstructure unit includes a second protrusion 324 and a second groove 325; and the third microstructure unit includes a third protrusion 326 and a third groove 327. The width of the first protrusion 322 is p1 = 0.2 μm, the width of the second protrusion 324 is p2 = 0.25 μm, the width of the third protrusion 326 is p3 = 0.3 μm, the width of the first groove 323 is f1 = 0.1 μm, the width of the second groove 325 is f2 = 0.15 μm, and the width of the third groove 327 is f3 = 0.25 μm. The height of the first protrusion 322, the second protrusion 324, and the third protrusion 326 is 0.2 μm.

[0090] Please see Figure 8According to the reflection efficiency curve of the multispectral reflective layer obtained in this embodiment in the visible light band, the reflectivity for light with a wavelength of 450nm is greater than 60%, the reflectivity for light with a wavelength of 540nm is greater than 60%, and the reflectivity for light with a wavelength of 640nm is greater than 20%.

[0091] This application also provides a method for preparing the reflective unit shown above, the method comprising:

[0092] S21: Provide a substrate layer, and spin-coat photoresist on the substrate layer;

[0093] S22: Patterning of microstructure layers on photoresist;

[0094] S23: Transfer the pattern of the microstructure layer to the base layer to form a multispectral reflective layer;

[0095] S24: Provides a transfer layer to transfer the multispectral reflective layer to the transfer layer;

[0096] S25: The transfer layer is attached to the first transparent plate to obtain the reflective unit.

[0097] The microstructure layer is patterned using methods such as photolithography or exposure, and the pattern is transferred to the substrate layer using methods such as ion etching or physicochemical reaction. The transfer layer can be made of flexible acrylic, resin, or plastic, but is not limited to these, and will not be listed here. The multispectral reflective layer can be transferred to the transfer layer via imprinting, i.e., fixing the multispectral reflective layer onto the transfer layer for easier subsequent use.

[0098] This application also provides a vehicle including the augmented reality head-up display device shown above, forming a virtual image in front of the windshield. The vehicle can be a bicycle, an electric vehicle, etc., such as a pure electric vehicle, a range-extended electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a new energy vehicle, etc., without specific limitation. The multispectral reflective layer helps improve display efficiency and enhances the versatility of windshield design. This multispectral reflective layer enhances the first reflection of the windshield and weakens or even eliminates the second reflection, thereby effectively eliminating ghosting.

[0099] In summary, the augmented reality head-up display device of the present invention has a multispectral reflective layer with a certain bandwidth for red, green and blue multi-band light on the first transparent plate near the optical waveguide unit. This layer reflects the image light, so that less image light passes through the first light-transmitting plate and is incident on other transparent plates, thereby effectively eliminating ghosting and improving the quality and efficiency of the displayed image.

[0100] Meanwhile, the multispectral reflective layer provides high reflectivity in the narrow bandwidth of the red, green, and blue main wavelengths, allowing some light to pass through while preventing all light from being reflected, thus avoiding the mirror effect and improving safety performance.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An augmented reality head-up display device, characterized in that, The device includes an image unit, an optical waveguide unit, and a reflection unit. The image unit generates image light rays and guides the image light rays to be incident on the surface of the optical waveguide unit. The optical waveguide unit conducts the image light rays and emits them toward the reflection unit. The reflection unit reflects the image light rays to the human eye and generates a virtual image. The reflection unit includes a transparent component with a reflective function and a multispectral reflective layer disposed on the transparent component. The transparent component includes at least two stacked transparent plates, and the multispectral reflective layer is disposed on a first transparent plate close to the optical waveguide unit. The multispectral reflective layer includes a base layer and a microstructure layer formed on the base layer. The microstructure layer includes a plurality of repeating microstructures, each microstructure including at least three microstructure units. Each microstructure unit has a different width and includes a protrusion and a groove adjacent to the protrusion. The width of the protrusion ranges from 100 to 400 nm, the height of the protrusion ranges from 50 to 300 nm, and the width of the groove ranges from 50 to 300 nm. The optical waveguide unit includes at least one optical waveguide, a first light-shielding layer disposed on one side of the optical waveguide, and a second light-shielding layer disposed on the other side of the optical waveguide. The first light-shielding layer is used to absorb light transmitted from the optical waveguide, and the second light-shielding layer is used to absorb light transmitted and / or reflected from the optical waveguide, as well as sunlight transmitted from the outside. The projection area of ​​the first light-shielding layer on the optical waveguide surface covers the projection area of ​​the coupling region on the optical waveguide surface, and the projection area and the coupling region of the first light-shielding layer on the optical waveguide surface are separated from each other. The projection area of ​​the second light-shielding layer on the optical waveguide surface covers the projection area of ​​the coupling region on the optical waveguide surface, and the projection area of ​​the second light-shielding layer on the optical waveguide surface and the projection area of ​​the image unit on the optical waveguide surface are disposed separately.

2. The augmented reality head-up display device as described in claim 1, characterized in that, The multispectral reflective layer includes at least one low-refractive-index layer and at least one high-refractive-index layer. The multispectral reflective layer can be expressed as (LH)^m, where L is the low-refractive-index layer, H is the high-refractive-index layer, and m is the number of stacking periods. The refractive index of the high-refractive-index layer and the refractive index of the low-refractive-index layer differ by at least 0.

1.

3. The augmented reality head-up display device as described in claim 2, characterized in that, The thickness of the low refractive index layer ranges from 0 to 300 nm; the thickness of the high refractive index layer ranges from 0 to 100 nm; the number of stacking periods m is 2 to 50; and the first refractive index layer in the multispectral reflective layer, which is located near the first transparent plate, is the low refractive index layer.

4. The augmented reality head-up display device as described in claim 2, characterized in that, The refractive index of the low-refractive-index layer ranges from 1.3 to 1.78; the refractive index of the high-refractive-index layer ranges from 1.8 to 2.

9.

5. The augmented reality head-up display device as described in claim 2, characterized in that, The low refractive index layer is made of one or more of silicon oxide, aluminum oxide, and magnesium fluoride; the high refractive index layer is made of one or more of titanium oxide, iron oxide, niobium oxide, tantalum oxide, zirconium oxide, chromium oxide, cerium oxide, and cobalt oxide.

6. The augmented reality head-up display device as claimed in claim 2, characterized in that, A matching layer is further provided between the multispectral reflective layer and the first transparent plate, and the refractive index of the matching layer is 2.0~2.

9.

7. The augmented reality head-up display device as claimed in claim 1, characterized in that, The refractive index of the base layer and the microstructure layer is 1.4~1.

7.

8. The augmented reality head-up display device as claimed in claim 1, characterized in that, The transparent component is a double-layered windshield.

9. A vehicle, characterized in that, Includes the augmented reality head-up display device as described in any one of claims 1-8.

Images