Head-up display devices and vehicles

Abstract

This application discloses a head-up display (HUD) device and a vehicle, belonging to the field of image display. The HUD device includes an optical waveguide, an optical engine, and a focal length adjustment layer. The optical waveguide has an input region and an output region. The optical engine is located on one side of the optical waveguide, and its light output direction faces the input region. The focal length adjustment layer is located between the optical waveguide and the windshield, and its orthographic projection onto the optical waveguide overlaps with the output region. The optical engine emits an image beam toward the input region. The optical waveguide transmits the image beam from the input region to the output region and guides it to the focal length adjustment layer. The focal length adjustment layer adjusts the focal length of at least a portion of the image beam emitted from the output region to produce a first image and a second image with different depths of field. This application achieves images with different depths of field through the focal length adjustment layer, thus realizing dual-focal-plane display without the need for two sets of optical engines, effectively reducing the size of the HUD device.

Description

Technical Field

[0001] This application relates to the field of image display, and in particular to a head-up display device and a vehicle. Background Technology

[0002] A head-up display (HUD) is an advanced driver assistance system whose main function is to project important driving information directly onto the windshield in front of the driver, allowing the driver to access this information without looking down.

[0003] Currently, most head-up display devices used in the market are augmented reality head-up display devices (AR HUDs). AR HUDs typically employ an off-axis reflection scheme based on freeform surface mirrors and use two sets of optical engines to achieve dual focal planes.

[0004] However, using two sets of optical engines to achieve dual focal planes will further increase the size of the AR HUD. Summary of the Invention

[0005] This application provides a head-up display device and a vehicle. It solves the problem of large size in existing head-up display devices when implementing dual focal planes. The technical solution is as follows:

[0006] In a first aspect, a head-up display device is provided, comprising: an optical waveguide, an optomechanical system, and a focus adjustment layer;

[0007] The optical waveguide has an input region and an output region;

[0008] The optical engine is located on one side of the optical waveguide, and the light output direction of the optical engine is towards the coupling region;

[0009] The focal length adjustment layer is located between the optical waveguide and the windshield, and the orthographic projection of the focal length adjustment layer on the optical waveguide overlaps with the coupling region.

[0010] The optical engine is used to emit an image beam toward the coupling region; the optical waveguide is used to transmit the image beam from the coupling region to the coupling region and guide it to the focal length adjustment layer through the coupling region; the focal length adjustment layer is used to adjust the focal length of at least a portion of the image beam emitted from the coupling region to produce a first image and a second image with different depths of field.

[0011] Optionally, the coupling region includes: a near-view coupling region and a far-view coupling region;

[0012] The focal length adjustment layer includes a first lens unit, the orthographic projection of the first lens unit on the optical waveguide overlaps with the near-field coupling region, and the first lens unit is used to reduce the focal length of the image beam emitted from the near-field coupling region to generate a first image.

[0013] The image beam emitted from the distant coupling area generates the second image, and the depth of field of the first image is less than the depth of field of the second image.

[0014] Optionally, the focal length adjustment layer further includes a second lens unit, the orthographic projection of the second lens unit on the optical waveguide overlapping the distant coupling region, the second lens unit being used to reduce the focal length of the image beam emitted from the distant coupling region to generate the second image;

[0015] The degree to which the second lens unit reduces the focal length of the image beam emitted from the distant coupling area is less than the degree to which the first lens unit reduces the focal length of the image beam emitted from the near coupling area.

[0016] Optionally, the image beam emitted by the optomechanical system includes: a first image beam and a second image beam, wherein the first image beam and the second image beam have different field of view angles;

[0017] The first image beam is used to be transmitted to the near-field coupling area through the optical waveguide, and the second image beam is used to be transmitted to the far-field coupling area through the optical waveguide.

[0018] Optionally, there are two optical waveguides, one of which is a first optical waveguide and the other is a second optical waveguide;

[0019] The first optical waveguide and the second optical waveguide are stacked in the light output direction of the optical engine, and the first optical waveguide is closer to the optical engine than the second optical waveguide;

[0020] The coupling-out region on the first optical waveguide is the near-view coupling-out region, and the coupling-out region on the second optical waveguide is the far-view coupling-out region; and the coupling-in region on the first optical waveguide is used to couple in the first image beam, and the coupling-in region on the second optical waveguide is used to couple in the second image beam.

[0021] The first lens unit is located between the first optical waveguide and the second optical waveguide.

[0022] Optionally, the optical waveguide includes: an optical waveguide body, a coupling grating, and a coupling grating; the optical waveguide body has the coupling region and the coupling region, the coupling grating is located in the coupling region, and the coupling grating is located in the coupling region.

[0023] Optionally, the brightness of the first image beam emitted by the optomechanical system is less than the brightness of the second image beam;

[0024] Alternatively, the height of the coupling grating at the near-field coupling area is less than the height of the coupling grating at the far-field coupling area, so that the brightness of the first image beam after being coupled out by the near-field coupling area is less than the brightness of the second image beam after being coupled out by the near-field coupling area.

[0025] Optionally, the optical waveguide further includes: a folding grating;

[0026] The folding grating is located between the input grating and the output grating, and the folding grating is used to guide the image beam coupled into the input grating to the output grating.

[0027] On the other hand, a vehicle is provided, including: a cockpit, and a head-up display installed in the cockpit, the head-up display being as described above.

[0028] Optionally, the cockpit includes the windshield, the focus adjustment layer, the optical waveguide, and the windshield are spaced apart, and the distance between the focus adjustment layer and the optical waveguide is smaller than the distance between the focus adjustment layer and the windshield.

[0029] The beneficial effects of the technical solutions provided in this application include at least the following:

[0030] An image beam emitted from the optical engine is transmitted from the coupling region to the coupling region via an optical waveguide, and then guided to a focus adjustment layer via the coupling region. The focus adjustment layer is used to adjust the focal length of at least a portion of the image beam emitted from the coupling region, thereby producing a first image and a second image with different depths of field. In this way, images with different depths of field can be realized through the focus adjustment layer, thus achieving dual-focal-plane display without the need for two sets of optical engines to achieve dual-focal-plane display. This reduces the size of the head-up display device and lowers the cost. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A schematic diagram of the basic component structure of a head-up display device provided in this application embodiment;

[0033] Figure 2This is a schematic diagram of an optical waveguide structure provided in an embodiment of this application;

[0034] Figure 3 This is a diagram illustrating the partitioned display mechanism of a head-up display device provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the viewing angle partitioning of a head-up display device provided in an embodiment of this application;

[0036] Figure 5 This is a schematic diagram of the grating arrangement in a head-up display device provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the grating arrangement in another head-up display device provided in this application embodiment;

[0038] Figure 7 This is a schematic diagram of another basic component structure of a head-up display device provided in an embodiment of this application;

[0039] Figure 8 This is a schematic diagram of the basic component structure of another head-up display device provided in the embodiments of this application;

[0040] Figure 9 This is a schematic diagram of an imaging device for a head-up display provided in an embodiment of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0042] In related technologies, head-up display devices (HUDs) employ an AR (Augmented Reflective) HUD display solution. AR HUDs typically utilize off-axis reflection based on freeform surface mirrors, where the field of view (FOV) and product volume are mutually constrained. Currently, mainstream AR HUDs have an FOV of 13° × 5° and a volume of approximately 10L. Increasing the FOV to 20° × 5° would increase the volume to around 15L, and increasing it to 30° × 5° would increase it to around 24L. However, due to limitations in current vehicle interior space, the FOV of AR HUDs remains at 13° × 5°. Furthermore, achieving dual-focal-plane display typically requires two optical engines, further increasing the AR HUD's volume and cost.

[0043] The head-up display (HUD) provided in this application is intended for use as a driver assistance system in vehicles, aiming to solve the size problem existing when adopting AR HUD display solutions. Taking the application of the HUD in an automobile as an example, the advantages of this HUD are illustrated below. The technical solution of the HUD is described as follows:

[0044] Please see Figures 1-2 , Figure 1 This is a schematic diagram of the basic component structure of a head-up display device provided in an embodiment of this application. Figure 2 This is a schematic diagram of an optical waveguide 10 structure provided in an embodiment of this application. The head-up display device provided in this embodiment includes: an optical waveguide 10, an optomechanical system 20, and a focus adjustment layer 30.

[0045] The optical waveguide 10 has a coupling-in region 10a and a coupling-out region 10b.

[0046] Optical mechanism 20 is located on one side of optical waveguide 10, and the light output direction of optical mechanism 20 is towards coupling region 10a.

[0047] The focus adjustment layer 30 is located between the optical waveguide 10 and the windshield 40, and the orthographic projection of the focus adjustment layer 30 on the optical waveguide 10 overlaps with the coupling region 10b.

[0048] The optical engine 20 emits an image beam toward the coupling region 10a. The optical waveguide 10 transmits the image beam from the coupling region 10a to the coupling region 10b, and guides it through the coupling region 10b to the focus adjustment layer 30. The focus adjustment layer 30 adjusts the focal length of at least a portion of the image beam emitted from the coupling region 10b to produce a first image and a second image with different depths of field.

[0049] In the head-up display device provided in this application embodiment, the optical waveguide 10 transmits the image beam emitted from the optical engine 20 from the coupling region 10a to the coupling region 10b, and then guides the image beam to the focus adjustment layer 30 through the coupling region 10b. The focus adjustment layer 30 is used to adjust the focal length of at least a portion of the image beam emitted from the coupling region 10b to generate a first image and a second image with different depths of field. By using the optical waveguide 10 to transmit the image beam emitted from the optical engine 20, a small-volume, large-field-of-view (FOV) display can be achieved, eliminating the constraint between the FOV of the image beam and the size of the head-up display device. When an increased FOV is required, an image beam with a corresponding FOV can be directly emitted from the optical engine 20 without increasing the size of the head-up display device. The focus adjustment layer 30 can realize images with different depths of field, thereby achieving dual-focal-plane display without the need for two sets of optical engines 20 to achieve dual-focal-plane display, thus reducing both the size of the head-up display device and its cost.

[0050] It should be noted that the first and second images generated in the head-up display are transmitted to the windshield 40 and reflected by the windshield 40 to the eye box 50, which is also the location of the driver's eyes inside the vehicle.

[0051] Please see Figure 2In some feasible implementations, the coupling region 10b includes a near-view coupling region 10b1 and a far-view coupling region 10b2.

[0052] The focal length adjustment layer 30 includes a first lens unit 31, the orthographic projection of the first lens unit 31 on the optical waveguide 10 overlaps with the near-field coupling region 10b1, and the first lens unit 31 is used to reduce the focal length of the image beam emitted from the near-field coupling region 10b1 to generate a first image.

[0053] The image beam emitted from the distant coupling region 10b2 produces a second image, and the depth of field of the first image is less than the depth of field of the second image.

[0054] By reducing the focal length of the image beam coupled from the near-field coupling area 10b1 using the first lens unit 31, the depth of field of the first image is smaller than that of the second image, meaning the imaging distance of the first image is smaller than that of the second image. Thus, the image beam emitted from the optical engine 20, after being reflected by the windshield 40 to the driver's eyes inside the vehicle, can present two focal planes with different depths of field. By setting the first lens unit 31 at the near-field coupling area 10b1 to achieve a dual-focal-plane design, the size of the head-up display device can be simplified, and the cost of implementing a dual-focal-plane design can be reduced.

[0055] For example, the first lens unit 31 is an optical element that can achieve optical focal length adjustment, such as a common optical lens, a liquid crystal lens, or a Fresnel lens. The first lens unit 31 uses one lens or a combination of multiple lenses. When the first lens unit 31 uses one lens, it facilitates the thinner design of the focal length adjustment layer 30. When the first lens unit 31 uses a combination of multiple lenses, such as a combination of two lenses, the focal length can be reduced by combining the two lenses, and the chromatic aberration and phase aberration that exist during light transmission can be corrected by combining the two lenses, thus ensuring image quality.

[0056] In some feasible implementations, the focal length adjustment layer 30 further includes a second lens unit 32, the orthographic projection of the second lens unit 32 on the optical waveguide 10 overlapping with the distant coupling region 10b2, the second lens unit 32 being used to reduce the focal length of the image beam emitted from the distant coupling region 10b2 to generate a second image.

[0057] The second lens unit 32 reduces the focal length of the image beam emitted from the distant coupling region 10b2 to a lesser extent than the first lens unit 31 reduces the focal length of the image beam emitted from the near coupling region 10b1.

[0058] The second lens unit 32 reduces the focal length of the image beam coupled from the distant coupling region 10b2, and the degree to which the second lens unit 32 reduces the focal length of the image beam emitted from the distant coupling region 10b2 is less than the degree to which the first lens unit 31 reduces the focal length of the image beam emitted from the near coupling region 10b1, so that the head-up display device can generate two focal planes with different imaging distances. The first lens unit 31 and the second lens unit 32 work together to easily generate two focal planes with different depths of field or different imaging distances according to imaging requirements, which facilitates the precise design of the head-up display device's imaging. The focal length adjustment layer 30 uses a combination design of the first lens unit 31 and the second lens unit 32 to achieve dual focal plane adjustment, which is simple in structure, small in size, and low in cost.

[0059] For example, the second lens unit 32 can also be an ordinary optical lens, a liquid crystal lens, a Fresnel lens, or other optical element capable of adjusting the optical focal length. The second lens unit 32 can be a single lens or a combination of multiple lenses. The second lens unit 32 only needs to be able to achieve the corresponding focal length adjustment; this application does not impose specific limitations.

[0060] The head-up display (HUD) is based on the dual-focal-plane AR HUD display mechanism of the optical waveguide 10. Its information needs fall into three main categories: first, real-time understanding of vehicle status; second, real-time access to navigation information to make driving decisions; and third, timely awareness of potential hazards in the driving environment. Based on the requirements of AR HUD, this application displays these contents at two different depths of field, placing information affecting the driver's driving decisions at the highest level to improve user cognitive efficiency, reduce cognitive burden, and enhance driving safety.

[0061] Specifically, the first image is a close-up view with an imaging distance of 1 to 1.5 meters, used to display instrument panel information, while the second image is a distant view with an imaging distance of >7.5 meters (for example, the imaging distance of the second image is 20 meters), used to display navigation prompts, driving warnings, etc.

[0062] The imaging distance corresponding to the first image is adjusted by the first lens unit 31, and the imaging distance corresponding to the second image is adjusted by the second lens unit 32.

[0063] In other feasible implementations, the second lens unit 32 may not be provided at the distant coupling area 10b2, that is, the focal length of the second image coupled out of the distant coupling area 10b2 is not adjusted, so that the second image is imaged at infinity. In this way, the first image and the second image can also form a dual-focal plane display effect.

[0064] In some feasible implementations, the image beam emitted by the optomechanical 20 includes a first image beam and a second image beam, the first image beam and the second image beam having different field of view angles.

[0065] For example, the FOV corresponding to the first image beam is ±18° in the horizontal direction and -5 to -3° in the vertical direction, while the FOV corresponding to the second image beam is ±18° in the horizontal direction and 0 to 5° in the vertical direction.

[0066] The first image beam is used to transmit to the near-field coupling area 10b1 through the optical waveguide 10, and the second image beam is used to transmit to the far-field coupling area 10b2 through the optical waveguide 10.

[0067] By emitting a first image beam and a second image beam with different field of view from the optical engine 20, the first image beam is transmitted to the near-field coupling area 10b1 through the optical waveguide 10, and the second image beam is transmitted to the far-field coupling area 10b2 through the optical waveguide 10. Combined with the focal length adjustment layers 30 correspondingly set at the near-field coupling area 10b1 and the far-field coupling area 10b2, the first image and the second image at different imaging distances can have different field of view, improving the imaging effect and providing users with a better user experience. It can also solve the problems of visual fatigue and convergence-focusing (VAC effect) conflict caused by prolonged viewing of existing single-focal-plane AR HUD displays.

[0068] Please see Figures 1-2 In some feasible embodiments, the optical waveguide 10 includes: an optical waveguide body 11, a coupling grating 12, and a coupling grating 13. The optical waveguide body 11 has a coupling region 10a and a coupling region 10b, the coupling grating 12 is located in the coupling region 10a, and the coupling grating 13 is located in the coupling region 10b.

[0069] The optomechanical unit 20, also known as the image generation unit (PGU), consists of a light source, optical films, and other optical components, and is used to generate an image beam. The coupling grating 12 couples the collimated image beam from the optomechanical unit 20 into the optical waveguide body 11. The optical waveguide body 11 performs total internal reflection of the image beam coupled by the coupling grating 12 to the output grating 13. The output grating 13 couples the totally internally reflected image beam from the optical waveguide body 11 to the focus adjustment layer 30.

[0070] Specifically, the optical engine 20 is a high-strength, small-sized PGU, such as LCOS, Mini-LED, or Micro-LED. The optical waveguide body 11 is a waveguide substrate made of glass, with a refractive index of 1.5 to 2.1 to improve the field of view (FOV). The optical waveguide 10 can also be made of resin glass with a higher refractive index to reduce the weight of the AR HUD. The coupling grating 12 and the coupling grating 13 can be any combination of a transmission grating and a reflection grating: when the coupling grating 12 couples the image beam into the optical waveguide body 11 in a transmission manner, the coupling grating 12 is a transmission grating; when the coupling grating 12 couples the image beam into the optical waveguide body 11 in a reflection manner, the coupling grating 12 is a reflection grating; when the coupling grating 13 couples the image beam out of the optical waveguide body 11 in a transmission manner, the coupling grating 13 is a transmission grating; when the coupling grating 13 couples the image beam out of the optical waveguide body 11 in a reflection manner, the coupling grating 13 is a reflection grating.

[0071] For example, please refer to Figure 1 The coupling grating 12, the coupling grating 13, and the optomechanical unit 20 are all located on the same side of the optical waveguide body 11. The coupling grating 12 is a transmission grating, and the coupling grating 13 is a reflection grating. The coupling grating 12 and the coupling grating 13 are directly integrated into the optical waveguide body 11. This facilitates the fabrication of the optical waveguide 10 and enables a compact design of the head-up display device, saving interior space when using the head-up display device.

[0072] In some feasible implementations, the coupling grating 12 and the coupling grating 13 have the same period in order to ensure the consistency of the incident angle and the exit angle.

[0073] Figure 3 This is a diagram illustrating the partitioned display mechanism of a head-up display device according to an embodiment of this application. Please refer to [link / reference]. Figure 3 The first image beam and the second image beam with different FOVs come from different parts of the coupling grating 13. By placing lens units with different optical powers (i.e., the first lens unit 31 and the second lens unit 32) at different positions in front of the coupling grating 13, first images and second images with different depths of field can be formed for the first image beam and the second image beam with different FOVs. The first images and the second images with different depths of field form two virtual image surfaces with different imaging positions at the eye box 50.

[0074] Figure 4 This is a schematic diagram of the viewing angle partitioning of a head-up display device provided in an embodiment of this application. Please refer to [link / reference]. Figure 4For different positions A and B on the eyepiece 50: horizontal upward light comes from the same grating area, while vertical light comes from different grating areas. For different positions A and C on the eyepiece 50: vertical light comes from the same grating area, while horizontal light comes from different grating areas. This application achieves dual-focal-plane display by adding a focal length adjustment layer 30 corresponding to the near-field coupling area 10b1 and the far-field coupling area 10b2 on the light-emitting side of the optical waveguide body 11.

[0075] In some feasible implementations, the brightness of the first image beam emitted from the optomechanical 20 is less than the brightness of the second image beam. Alternatively, the height of the coupling grating 13 at the near-field coupling region 10b1 is less than the height of the coupling grating 13 at the far-field coupling region 10b2, so that the brightness of the first image beam after being coupled out by the near-field coupling region 10b1 is less than the brightness of the second image beam after being coupled out by the near-field coupling region 10b1.

[0076] The second image beam corresponds to a second image with a longer imaging distance. The second image is used to display important information related to driving safety, such as navigation prompts and driving warnings. Setting the brightness of the second image beam to be larger will make the virtual image surface produced by the second image brighter, so that the driver in the vehicle can obtain the information transmitted by the second image in a timely manner, thereby improving driving safety.

[0077] For example, the brightness of the first image corresponding to the first image beam is 2000 nits, and the brightness of the second image corresponding to the second image beam is 15000 nits. The first image can be displayed continuously, and the second image can be displayed intermittently.

[0078] In other feasible embodiments, the head-up display device may further include a filter, for example, placed at any one of the light-emitting side of the coupling grating 13, the light-incident side of the focus adjustment layer 30, and the light-emitting side of the focus adjustment layer 30, so that the beam brightness of the first image is less than the beam brightness of the second image. Although using a filter can create a difference in brightness between the first image and the second image, it sacrifices some brightness, resulting in a waste of beam brightness.

[0079] In some feasible implementations, the optical waveguide 10 further includes a folding grating 14. The folding grating 14 is located between the input grating 12 and the output grating 13, and is used to guide the image beam coupled into the input grating 12 to the output grating 13.

[0080] Figure 5 and Figure 6 These are all schematic diagrams illustrating the grating arrangement in a head-up display device provided in the embodiments of this application. For details, please refer to... Figures 5-6The coupling grating 12 and the folding grating 14 are aligned in the Y direction, and the folding grating 14 and the coupling grating 13 are aligned in the X direction. The coupling grating 12 is used to couple the image beam collimated by the optical engine 20 into the optical waveguide body 11 for total internal reflection transmission. When the optical waveguide body 11 transmits the image beam to the folding grating 14 by total internal reflection, the image beam is divided into two parts. One part continues to be transmitted by total internal reflection along the Y direction, realizing light expansion in the Y direction (Y-direction pupil expansion), and the other part is transmitted by total internal reflection along the X direction of the coupling grating 13. After the image beam is transmitted to the coupling grating 13, it is coupled out by the coupling grating 13, reflected by the windshield 40, and enters the human eye to form an image on the retina.

[0081] When the periods of the input grating 12 and the output grating 13 are the same, the sum of the grating vectors of the input grating 12, the output grating 13, and the folded grating 14 is 0. For example... Figures 5-6 As shown, the grating lines of the coupled grating 12 are parallel to the X-axis, the grating lines of the coupled grating 13 are parallel to the Y-axis, and the angle θ between the line direction of the folded grating 14 and the horizontal X-axis is 45°.

[0082] Figure 7 This is a schematic diagram of another basic component structure of a head-up display device provided in an embodiment of this application. Please refer to [link / reference]. Figure 7 In some feasible implementations, there are two optical waveguides 10, one of which is a first optical waveguide 110 and the other is a second optical waveguide 120.

[0083] The first optical waveguide 110 and the second optical waveguide 120 are stacked in the light output direction of the optomechanical 20, and the first optical waveguide 110 is closer to the optomechanical 20 than the second optical waveguide 120, while the second optical waveguide 120 is closer to the windshield 40 than the first optical waveguide 110.

[0084] The coupling-out region 10b on the first optical waveguide 110 is the near-view coupling-out region 10b1, and the coupling-out region 10b on the second optical waveguide 120 is the far-view coupling-out region 10b2. The coupling-in region 10a on the first optical waveguide 110 is used to couple in the first image beam, and the coupling-in region 10a on the second optical waveguide 120 is used to couple in the second image beam.

[0085] The first lens unit 31 is located between the first optical waveguide 110 and the second optical waveguide 120.

[0086] The coupling region 10b on the first optical waveguide 110 is designated as the near-field coupling region 10b1, and the coupling region 10b on the second optical waveguide 120 is designated as the far-field coupling region 10b2. The second image beam emitted from the far-field coupling region 10b2 generates a second image. A corresponding first lens unit 31 is provided in the near-field coupling region 10b1. The focal length of the first image beam emitted from the near-field coupling region 10b1 is reduced by the first lens unit 31 to generate a first image. After the focal length is reduced by the first lens unit 31, the depth of field of the first image is smaller than that of the second image. This allows the image beam emitted from the optical engine 20 to present two focal planes with different depths of field after being reflected by the windshield 40 to the position of the driver's eyes inside the vehicle. By setting the first lens unit 31 in the near-field coupling region 10b1 to achieve a dual-focal-plane design, the size of the head-up display device can be simplified, and the cost of achieving a dual-focal-plane design can be reduced. The optical waveguides 10 are two in number and stacked, which facilitates flexible design of the head-up display device, saves space, allows for the sharing of a single optical engine 20, and reduces costs.

[0087] Figure 8 This is a schematic diagram of the basic component structure of another head-up display device provided in the embodiments of this application. For details, please refer to [link / reference]. Figure 8 The first optical waveguide 110 includes a first optical waveguide body 111, a first coupling grating 112, and a first coupling grating 113. The second optical waveguide 120 includes a second optical waveguide body 121, a second coupling grating 122, and a second coupling grating 123.

[0088] The first coupling grating 112 is integrated into the coupling region 10a of the first optical waveguide body 111, and is used to couple the first image beam emitted from the optomechanical 20 into the first optical waveguide body 111. The first optical waveguide body 111 is used to perform total internal reflection of the first image beam coupled into the first coupling grating 112 to the near-field coupling region 10b1. The first coupling grating 113 is integrated into the near-field coupling region 10b1 of the first optical waveguide body 111, and is used to couple the first image beam out of the first optical waveguide body 111.

[0089] The second coupling grating 122 is integrated into the coupling region 10a of the second optical waveguide body 121, and is used to couple the second image beam emitted from the optomechanical 20 into the second optical waveguide body 121. The second optical waveguide body 121 is used to perform total internal reflection of the second image beam coupled into the second coupling grating 122 to the distant output region 10b2. The second output grating 123 is integrated into the distant output region 10b2 of the second optical waveguide body 121, and is used to couple the second image beam out of the second optical waveguide body 121.

[0090] The first coupling grating 112 has a greater diffraction efficiency for the first image beam than for the second image beam, so as to couple the first image beam into the first optical waveguide body 111. The second coupling grating 122 has a greater diffraction efficiency for the second image beam than for the first image beam, so as to couple the second image beam into the second optical waveguide body 121.

[0091] The first input grating 112 and the first output grating 113 can be located on either the upper or lower side of the first optical waveguide body 111, and the second input grating 122 and the second output grating 123 can be located on either the upper or lower side of the second optical waveguide body 121. The first input grating 112, the first output grating 113, the second input grating 122, and the second output grating 123 are all either transmission gratings or reflection gratings, with the type of grating determined specifically by the position of the grating and the method of transmitting the image beam.

[0092] For example, Figure 8 The optical engine 20 is located on the lower side of the first optical waveguide body 111. The first coupling grating 112 is located on the lower side of the first optical waveguide body 111 and couples the first image beam emitted from the optical engine 20 into the first optical waveguide body 111 via transmission; therefore, the first coupling grating 112 is a transmission grating. The determination of the grating types of the first coupling grating 113, the second coupling grating 122, and the second coupling grating 123 is similar and will not be analyzed further. Figure 8 The types of gratings in the first output grating 113, the second input grating 122, and the second output grating 123.

[0093] The second image beam corresponds to a second image with a longer imaging distance. The second image is used to display important information related to driving safety. Setting the brightness of the second image beam or the second image to be larger can make the virtual image surface produced by the second image brighter, so that the driver in the vehicle can obtain the information transmitted by the second image in a timely manner, thereby improving driving safety.

[0094] In some feasible implementations, the brightness of the first image beam emitted from the optomechanical system 20 is less than the brightness of the second image beam. Alternatively, the grating height of the first coupling grating 112 is less than the grating height of the second coupling grating 122, resulting in a relatively higher coupling efficiency of the second coupling grating 122 for the second image beam, achieving the effect that the brightness of the second image beam is greater than the brightness of the first image beam. Or, the grating height of the first coupling grating 113 is less than the grating height of the second coupling grating 123, resulting in a relatively higher coupling efficiency of the second coupling grating 123 for the second image beam, achieving the effect that the brightness of the second image beam is greater than the brightness of the first image beam. Alternatively, a filter can be provided on any one of the light-emitting side of the first coupling grating 113, the light-incident side of the first lens unit 31, and the light-emitting side of the first lens unit 31, reducing the brightness of the first image beam or the first image, ultimately making the brightness of the first image less than the brightness of the second image.

[0095] Please see Figure 8 In some feasible embodiments, the focal length adjustment layer 30 further includes a second lens unit 32. The second lens unit 32 is located between the second optical waveguide body 121 and the windshield 40, and the orthographic projection of the second lens unit 32 on the second optical waveguide body 121 overlaps with the distant view coupling area 10b2. The second lens unit 32 is used to reduce the focal length of the second image beam emitted from the distant view coupling area 10b2 to generate a second image.

[0096] The degree to which the second lens unit 32 reduces the focal length of the second image beam emitted from the distant coupling region 10b2 is less than the degree to which the first lens unit 31 reduces the focal length of the first image beam emitted from the near coupling region 10b1.

[0097] The second lens unit 32 reduces the focal length of the second image beam coupled from the distant coupling region 10b2, and the degree to which the second lens unit 32 reduces the focal length of the second image beam emitted from the distant coupling region 10b2 is less than the degree to which the first lens unit 31 reduces the focal length of the first image beam emitted from the near coupling region 10b1, so that the head-up display device can generate two focal planes with different imaging distances. The first lens unit 31 and the second lens unit 32 work together to easily generate two focal planes with different depths of field or different imaging distances according to imaging requirements, which facilitates the precise design of the head-up display device's imaging. The focal length adjustment layer 30 uses a combination design of the first lens unit 31 and the second lens unit 32 to achieve dual focal plane adjustment, which is simple in structure, small in size, and low in cost.

[0098] In some feasible implementations, the near-field coupling region 10b1 in the first optical waveguide body 111 and the far-field coupling region 10b2 in the second optical waveguide body 121 are misaligned, so that the first lens unit 31 and the second lens unit 32 are misaligned, thereby avoiding the second lens unit 32 from affecting the focal length of the first image emitted by the first lens unit 31.

[0099] Figure 9 This is a schematic diagram of an imaging device for a head-up display provided in an embodiment of this application. Using the head-up display device in the above-disclosed embodiment of this application, a first image and a second image with different viewing angles, different depths of field, and different brightness can be seen at the eye box (i.e., at the driver's eye position inside the vehicle).

[0100] This application discloses a dual-focal-area AR HUD design based on an optical waveguide. Utilizing an optical engine 20 and a focal length adjustment layer 30, a dual-focal-area AR HUD can be achieved. Compared to existing mainstream dual-focal-area AR HUDs based on freeform surface mirrors, this design simplifies the structure and reduces costs. Furthermore, by using an optical waveguide 10 to realize the AR HUD display, a small-volume, large-field-of-view (FOV) display can be achieved, overcoming the limitations imposed by the size and FOV constraints of existing AR HUDs based on off-axis freeform surface mirrors.

[0101] This application also provides a vehicle, including: a cockpit, and a head-up display device installed in the cockpit, wherein the head-up display device is the head-up display device described in the above embodiment.

[0102] Since the head-up display device described in the above embodiments has the advantages of simple structure and small size, vehicles using the head-up display device described in the above embodiments can save space in the cockpit, improve the space utilization rate in the cockpit, and provide a better experience for users in the cockpit.

[0103] Using the head-up display device in this application embodiment as a driving assistance system in a vehicle, a dual-focal-plane design can be achieved by using a single optical engine 20 through a focal length adjustment layer 30, which effectively reduces the cost of the driving assistance system in the vehicle, thereby reducing the cost of the vehicle.

[0104] The means of transportation provided in the embodiments of this application are, for example, cars, airplanes, etc.

[0105] In some feasible embodiments, the cockpit has a windshield 40, a focus adjustment layer 30, an optical waveguide 10 and the windshield 40 are spaced apart, and the distance between the focus adjustment layer 30 and the optical waveguide 10 is smaller than the distance between the focus adjustment layer 30 and the windshield 40.

[0106] The spacing between the focus adjustment layer 30 and the optical waveguide 10 prevents angular deviations in light transmission within the waveguide 10 when they are in close contact, ensuring accurate light transmission. The spacing between the focus adjustment layer 30 and the windshield 40 also prevents interference with the driver's view in the cockpit when they are in close contact, ensuring vehicle safety. The smaller spacing between the focus adjustment layer 30 and the optical waveguide 10 compared to the spacing between the focus adjustment layer 30 and the windshield 40 contributes to a more compact head-up display structure, thus saving space within the cockpit.

[0107] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0108] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0109] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A head-up display device, characterized in that, include: Optical waveguides, optomechanics, and focus adjustment layers; The optical waveguide has an input region and an output region; The optical engine is located on one side of the optical waveguide, and the light output direction of the optical engine is towards the coupling region; The image beam emitted by the optomechanism includes: a first image beam and a second image beam with different field of view. There are two optical waveguides, one is a first optical waveguide and the other is a second optical waveguide; the first optical waveguide and the second optical waveguide are stacked in the light output direction of the optical engine, and the first optical waveguide is closer to the optical engine than the second optical waveguide; the coupling region on the first optical waveguide is a near-field coupling region and the coupling region on the second optical waveguide is a far-field coupling region. The focal length adjustment layer includes a first lens unit located between the first optical waveguide and the second optical waveguide, and a second lens unit located between the second optical waveguide and the windshield; the orthographic projection of the first lens unit on the first optical waveguide overlaps with the near-field coupling area; the orthographic projection of the second lens unit on the second optical waveguide overlaps with the far-field coupling area. The first image beam is used to couple into the first optical waveguide through the coupling area on the first optical waveguide, and is transmitted to the near-field coupling area through the first optical waveguide; the first optical waveguide is used to guide the first image beam from the near-field coupling area to the first lens unit; the first lens unit is used to reduce the focal length of the first image beam emitted from the near-field coupling area to generate the first image. The second image beam is used to couple into the second optical waveguide through the coupling area on the second optical waveguide, and is transmitted to the distant coupling area through the second optical waveguide; the second optical waveguide is used to guide the second image beam from the distant coupling area to the second lens unit; the second lens unit is used to reduce the focal length of the second image beam emitted from the distant coupling area to generate a second image; the degree to which the second lens unit reduces the focal length of the image beam emitted from the distant coupling area is less than the degree to which the first lens unit reduces the focal length of the image beam emitted from the near coupling area.

2. The head-up display device according to claim 1, characterized in that, The optical waveguide includes: an optical waveguide body, a coupling grating, and a coupling grating; the optical waveguide body has the coupling region and the coupling region, the coupling grating is located in the coupling region, and the coupling grating is located in the coupling region.

3. The head-up display device according to claim 2, characterized in that, The brightness of the first image beam emitted by the optical engine is less than the brightness of the second image beam. Alternatively, the height of the coupling grating at the near-field coupling area is less than the height of the coupling grating at the far-field coupling area, so that the brightness of the first image beam after being coupled out by the near-field coupling area is less than the brightness of the second image beam after being coupled out by the near-field coupling area.

4. The head-up display device according to claim 2, characterized in that, The optical waveguide further includes: a folding grating; The folding grating is located between the input grating and the output grating, and the folding grating is used to guide the image beam coupled into the input grating to the output grating.

5. A means of transportation, comprising: A cockpit, and a head-up display device installed in the cockpit, wherein the head-up display device is the head-up display device according to any one of claims 1 to 4.

6. The means of transportation according to claim 5, characterized in that, The cockpit includes the windshield, the focus adjustment layer, the optical waveguide, and the windshield are distributed at intervals, and the distance between the focus adjustment layer and the optical waveguide is smaller than the distance between the focus adjustment layer and the windshield.

Images