Head-up display device and vehicle

Abstract

The invention discloses a head-up display device and a vehicle, and belongs to the field of image display. The head-up display device comprises an optical waveguide, an optical machine and a focal length adjusting layer. The optical waveguide has a coupling-in region and a coupling-out region. The optical machine is located on one side of the optical waveguide, and the light emitting direction of the optical machine faces the coupling-in area. The focal length adjusting layer is located between the optical waveguide and the windshield, and the orthographic projection of the focal length adjusting layer on the optical waveguide is overlapped with the coupling-out area. The light machine is used for emitting an image light beam towards the coupling-in area. The optical waveguide is used for transmitting the image light beam from the coupling-in area to the coupling-out area and guiding the image light beam to the focal length adjusting layer through the coupling-out area. The focal length adjusting layer is used for adjusting the focal length of at least part of light beams in the image light beams emitted by the coupling-out area so as to generate a first image and a second image which are different in depth of field. According to the head-up display device, images with different depths of field can be realized through the focal length adjusting layer, so that double-focal-plane display is realized, two groups of optical machines are not needed to realize double focal planes, and the size of the head-up display device is effectively reduced.

Description

Technical Field

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

[0002] 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, so that the driver can obtain this information without lowering his head.

[0003] At present, most of the head-up display devices used in the market are augmented reality head-up display devices (AR HUD for short). AR HUD usually adopts an off-axis reflection solution based on a free-form surface reflector, and uses two sets of optical machines to achieve dual focal planes.

[0004] However, when two sets of optical machines are used to achieve dual focal planes, the volume of the AR HUD will be further increased. Summary of the invention

[0005] The present application provides a head-up display device and a vehicle. The problem of large volume of the head-up display device in the prior art when realizing dual focal planes can be solved. The technical solution is as follows:

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

[0007] The optical waveguide has an incoupling region and an outcoupling region;

[0008] The optical machine is located at one side of the optical waveguide, and the light output direction of the optical machine is toward the coupling-in area;

[0009] The focus adjustment layer is located between the optical waveguide and the windshield, and the orthographic projection of the focus adjustment layer on the optical waveguide overlaps with the outcoupling region;

[0010] Among them, the optical machine is used to emit an image light beam toward the coupling-in area; the optical waveguide is used to transmit the image light beam from the coupling-in area to the coupling-out area, and guide it to the focus adjustment layer through the coupling-out area; the focus adjustment layer is used to adjust the focus of at least part of the image light beam emitted from the coupling-out area to produce a first image and a second image with different depth of field.

[0011] Optionally, the outcoupling area includes: a near-view outcoupling area and a far-view outcoupling area;

[0012] The focal length adjustment layer comprises a first lens unit, the orthographic projection of the first lens unit on the optical waveguide overlaps with the near-view outcoupling area, and the first lens unit is used to reduce the focal length of the image light beam emitted from the near-view outcoupling area to generate a first image;

[0013] The image light beam emitted from the long-range outcoupling area generates the second image, and the depth of field of the first image is smaller 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 overlaps with the distant outcoupling area, and the second lens unit is used to reduce the focal length of the image light beam emitted from the distant outcoupling area to generate the second image;

[0015] The extent to which the second lens unit reduces the focal length of the image light beam emitted from the far-view out-coupling area is less than the extent to which the first lens unit reduces the focal length of the image light beam emitted from the near-view out-coupling area.

[0016] Optionally, the image beam emitted by the optical machine includes: a first image beam and a second image beam, and the first image beam and the second image beam have different field angles;

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

[0018] Optionally, the number of the optical waveguides is two, one of the two optical waveguides 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 and arranged in a light emitting direction of the optical machine, and the first optical waveguide is closer to the optical machine than the second optical waveguide;

[0020] The outcoupling area on the first optical waveguide is the near-view outcoupling area, and the outcoupling area on the second optical waveguide is the far-view outcoupling area; and the incoupling area on the first optical waveguide is used for coupling in the first image light beam, and the incoupling area on the second optical waveguide is used for coupling in the second image light beam;

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

[0022] Optionally, the optical waveguide comprises: an optical waveguide body, an incoupling grating and an outcoupling grating; the optical waveguide body has the incoupling region and the outcoupling region, the incoupling grating is located in the incoupling region, and the outcoupling grating is located in the outcoupling region.

[0023] Optionally, the brightness of the first image light beam emitted by the optical machine is smaller than the brightness of the second image light beam;

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

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

[0026] The folding grating is located between the coupling-in grating and the coupling-out grating, and is used to guide the image light beam coupled by the coupling-in grating to the coupling-out grating.

[0027] On the other hand, a vehicle is provided, 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 as described above.

[0028] Optionally, the cockpit has the windshield, and 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 brought by the technical solution provided by the embodiment of the present application include at least:

[0030] The image beam emitted by the optical machine is transmitted from the coupling-in area to the coupling-out area through the optical waveguide, and the image beam is guided to the focus adjustment layer through the coupling-out area. The focus adjustment layer is used to adjust the focus of at least part of the image beam emitted by the coupling-out area to generate 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, thereby realizing dual-focal plane display, without the need to use two sets of optical machines to realize dual-focal planes, which can reduce the size of the head-up display device and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

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

[0034] Figure 3 It is a diagram of a partition display mechanism of a head-up display device provided in an embodiment of the present application;

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

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

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

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

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

[0040] Fig. 9 This is a schematic diagram of imaging of a head-up display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0042] In the related technology, the head-up display device adopts the AR HUD display solution. AR HUD usually adopts an off-axis reflection solution based on a free-form surface reflector. In this solution, there is a mutually restrictive relationship between the field of view (FOV) and the product volume. The current mainstream AR HUD has a FOV of 13°×5°, and the volume of the AR HUD is about 10L. If the FOV is increased to 20°×5°, the volume of the AR HUD will become about 15L. If the FOV is increased to 30°×5°, the volume of the AR HUD will become about 24L. Limited by the current vehicle interior volume, the FOV of the AR HUD is 13°×5°. In addition, this solution usually requires two sets of optical machines 20 to achieve dual-focal plane display, which will further increase the volume of the AR HUD and increase the cost.

[0043] The head-up display device provided in this application is used as a driving assistance system in a vehicle, aiming to solve the volume problem existing when using an AR HUD display solution. Taking the head-up display device applied to a car as an example to illustrate the advantages of the head-up display device of this application, the technical solution of the head-up display device is introduced as follows:

[0044] See also Figure 1-Figure 2 , Figure 1 A schematic diagram of the basic components of a head-up display device provided in an embodiment of the present application is shown in FIG. Figure 2 1 is a schematic diagram of the structure of an optical waveguide 10 provided in an embodiment of the present application. The head-up display device provided in an embodiment of the present application includes: an optical waveguide 10, an optical engine 20 and a focus adjustment layer 30.

[0045] The optical waveguide 10 has an incoupling region 10a and a decoupling region 10b.

[0046] The optical engine 20 is located at one side of the optical waveguide 10 , and the light output direction of the optical engine 20 is toward the coupling-in region 10 a .

[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 outcoupling region 10 b .

[0048] The optical machine 20 is used to emit an image beam toward the coupling-in area 10a. The optical waveguide 10 is used to transmit the image beam from the coupling-in area 10a to the coupling-out area 10b, and guide the image beam to the focus adjustment layer 30 through the coupling-out area 10b. The focus adjustment layer 30 is used to adjust the focus of at least part of the image beam emitted from the coupling-out area 10b to generate a first image and a second image with different depths of field.

[0049] In the head-up display device provided in the embodiment of the present application, the optical waveguide 10 transmits the image beam emitted by the optical machine 20 from the coupling-in area 10a to the coupling-out area 10b, and guides the image beam to the focus adjustment layer 30 through the coupling-out area 10b. The focus adjustment layer 30 is used to adjust the focus of at least part of the image beam emitted by the coupling-out area 10b to generate a first image and a second image with different depths of field. The transmission of the image beam emitted by the optical machine 20 is realized by the optical waveguide 10, which can realize a small volume and a large FOV display, and eliminate the restrictive relationship between the FOV of the image beam and the volume of the head-up display device. When the FOV needs to be increased, the image beam with the corresponding FOV can be directly emitted by the optical machine 20 without increasing the volume of the head-up display device. Images with different depths of field can be realized through the focus adjustment layer 30, thereby realizing dual-focal plane display, without using two sets of optical machines 20 to realize dual focal planes, which can reduce the volume of the head-up display device and reduce costs.

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

[0051] See also Figure 2In some feasible implementations, the outcoupling area 10b includes: a near-view outcoupling area 10b1 and a far-view outcoupling area 10b2.

[0052] The focus 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-out area 10b1, and the first lens unit 31 is used to reduce the focus of the image light beam emitted from the near-field coupling-out area 10b1 to produce a first image.

[0053] The image light beam emitted from the long-range outcoupling area 10b2 generates a second image, and the depth of field of the first image is smaller than the depth of field of the second image.

[0054] The focal length of the image light beam coupled out of the near-field coupling-out area 10b1 is reduced by the first lens unit 31, so that the depth of field of the first image is smaller than the depth of field of the second image, that is, the imaging distance of the first image is smaller than the imaging distance of the second image. In this way, the image light beam emitted by the optical machine 20 can present two focal planes with different depths of field after finally being reflected by the windshield 40 to the position where the eyes of the driver in the car are located. The design of dual focal planes is realized by arranging the first lens unit 31 at the near-field coupling-out area 10b1, which can simplify the volume of the head-up display device and reduce the cost of realizing dual focal planes.

[0055] Exemplarily, the first lens unit 31 is an optical element that can adjust the focal length of light, such as a common optical lens, a liquid crystal lens, a Fresnel lens, etc. The first lens unit 31 uses a single lens or a combination of multiple lenses. When the first lens unit 31 uses a single lens, it is convenient for the thin and light design of the focal length adjustment layer 30. When the first lens unit 31 uses a combination of multiple lenses, for example, the first lens unit 31 uses a combination of two lenses, the focal length can be reduced by the combination of the two lenses, and the chromatic aberration and phase difference existing in the light transmission can be corrected by the two lenses to ensure the imaging quality.

[0056] In some feasible embodiments, the focal length adjustment layer 30 also includes: a second lens unit 32, the orthographic projection of the second lens unit 32 on the optical waveguide 10 overlaps with the distant outcoupling area 10b2, and the second lens unit 32 is used to reduce the focal length of the image light beam emitted from the distant outcoupling area 10b2 to produce a second image.

[0057] The degree to which the second lens unit 32 reduces the focal length of the image light beam emitted from the far-field outcoupling area 10b2 is smaller than the degree to which the first lens unit 31 reduces the focal length of the image light beam emitted from the near-field outcoupling area 10b1.

[0058] The focal length of the image light beam coupled out of the distant out-coupling area 10b2 is reduced by the second lens unit 32, and the degree to which the focal length of the image light beam emitted from the distant out-coupling area 10b2 is reduced by the second lens unit 32 is less than the degree to which the focal length of the image light beam emitted from the near-field out-coupling area 10b1 is reduced by the first lens unit 31, 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 cooperate to facilitate the generation of two focal planes with different depths of field or different imaging distances according to imaging requirements, which facilitates the precise design of the imaging of the head-up display device. The focal length adjustment layer 30 adopts the combined design of the first lens unit 31 and the second lens unit 32 to achieve dual focal plane adjustment, which has a simple structure, a small size and a low cost.

[0059] Exemplarily, the second lens unit 32 is also an optical element that can adjust the optical focal length, such as a common optical lens, a liquid crystal lens, a Fresnel lens, etc. The second lens unit 32 uses a single lens or a combination of multiple lenses. As long as the second lens unit 32 can achieve the corresponding focal length adjustment, the present application does not make any specific restrictions.

[0060] The head-up display device is based on the dual-focal AR HUD display mechanism of the optical waveguide 10. There are three types of information requirements: first, real-time understanding of vehicle status; second, real-time navigation information to make driving decisions; third, timely knowledge of potential dangers in the driving environment. According to the needs of AR HUD, this application displays these contents at two depths of field, placing the information that affects the driver's driving decision at the highest level to improve user cognitive efficiency, reduce cognitive burden, and improve driving safety.

[0061] Specifically, the first image is a close view with an imaging distance of 1 to 1.5 m, which is used to display instrument panel information; the second image is a long view with an imaging distance of > 7.5 m (for example, the imaging distance of the second image is 20 m), which is used to display navigation prompt information, driving warning information, 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 embodiments, the second lens unit 32 may not be provided at the distant out-coupling area 10b2, that is, the focal length of the second image coupled out from the distant out-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 may also form a dual-focal plane display effect.

[0064] In some feasible implementations, the image beam emitted by the optical machine 20 includes: a first image beam and a second image beam, and the first image beam and the second image beam have different field 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, and 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 light beam is used to be transmitted to the near-view outcoupling area 10b1 through the optical waveguide 10, and the second image light beam is used to be transmitted to the far-view outcoupling area 10b2 through the optical waveguide 10.

[0067] The optical machine 20 emits the first image beam and the second image beam with different viewing angles. The first image beam is used to be transmitted to the near-view coupling area 10b1 through the optical waveguide 10, and the second image beam is used to be transmitted to the far-view coupling area 10b2 through the optical waveguide 10. Combined with the focal length adjustment layer 30 correspondingly set at the near-view coupling area 10b1 and the far-view coupling area 10b2, the first image and the second image at different imaging distances can have different viewing angles, improve the imaging effect, and bring better user experience. And it can solve the problems of visual fatigue, convergence and focus (VAC effect) conflict caused by long-term viewing of the existing single-focal-plane AR HUD display.

[0068] See also Figure 1-Figure 2 In some feasible implementations, the optical waveguide 10 includes: an optical waveguide body 11, an incoupling grating 12, and an outcoupling grating 13. The optical waveguide body 11 has an incoupling region 10a and an outcoupling region 10b, the incoupling grating 12 is located in the incoupling region 10a, and the outcoupling grating 13 is located in the outcoupling region 10b.

[0069] The optical machine 20, also known as the Picture Generation Unit (PGU), is composed of a light source, an optical film and other optical components, and is used to generate an image beam. The coupling-in grating 12 is used to couple the image beam collimated by the optical machine 20 into the optical waveguide body 11. The optical waveguide body 11 is used to totally reflect the image beam coupled by the coupling-in grating 12 to the coupling-out grating 13. The coupling-out grating 13 is used to couple the image beam totally reflected in the optical waveguide body 11 out to the focus adjustment layer 30.

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

[0071] For example, see Figure 1 The coupling-in grating 12, the coupling-out grating 13 and the optical engine 20 are all located on the same side of the optical waveguide body 11, the coupling-in grating 12 is a transmission grating, the coupling-out grating 13 is a reflection grating, and the coupling-in grating 12 and the coupling-out grating 13 are directly integrated into the optical waveguide body 11. In this way, it is convenient to process the optical waveguide 10, and the head-up display device can be designed to be compact, so as to save space in the vehicle when the head-up display device is used.

[0072] In some feasible implementations, the periods of the coupling-in grating 12 and the coupling-out grating 13 are the same, so as to ensure the consistency of the incident angle and the emission angle.

[0073] Figure 3 This is a diagram of a partition display mechanism of a head-up display device provided in an embodiment of the present application. Please refer to Figure 3 The first image beam and the second image beam with different FOVs come from different parts of the outcoupling grating 13. By placing lens units with different optical focal lengths (i.e., the first lens unit 31 and the second lens unit 32) at different positions in front of the outcoupling grating 13, the first image and the second image beam with different FOVs can be formed with different depths of field. The first image and the second image with different depths of field form two virtual image planes with different imaging positions at the eye box 50.

[0074] Figure 4 This is a schematic diagram of a viewing angle partition of a head-up display device provided in an embodiment of the present application. Figure 4, for different positions A and B on the eye box 50: the light in the horizontal direction comes from the same grating area, and the light in the vertical direction comes from different grating areas. For different positions A and C on the eye box 50: the light in the vertical direction comes from the same grating area, and the light in the horizontal direction comes from different grating areas. The present application can realize dual-focal plane display by adding a focal length adjustment layer 30 corresponding to the near-view outcoupling area 10b1 and the far-view outcoupling 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 by the optical machine 20 is less than the brightness of the second image beam. Alternatively, the height of the coupling grating 13 at the near-field coupling-out area 10b1 is less than the height of the coupling grating 13 at the far-field coupling-out area 10b2, so that the brightness of the first image beam after being coupled out by the near-field coupling-out area 10b1 is less than the brightness of the second image beam after being coupled out by the near-field coupling-out area 10b1.

[0076] The second image beam corresponds to a second image at a farther imaging distance. The second image is used to display important information related to driving safety, such as navigation prompt information and driving warning information. Setting the brightness of the second image beam to be larger can correspondingly make the brightness of the virtual image surface produced by the second image larger, so as to facilitate the driver in the car to obtain the information transmitted by the second image in time, thereby improving driving safety.

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

[0078] In other feasible implementations, the head-up display device may further include: a filter, for example, a filter is placed at any one of the light-exiting side of the outcoupling grating 13, the light-entering side of the focus adjustment layer 30, and the light-exiting side of the focus adjustment layer 30, so that the light beam brightness of the first image is smaller than the light beam brightness of the second image. Although the use of a filter can make the brightness of the first image and the second image different, it will sacrifice a part of the brightness, resulting in a waste of light 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 coupling-in grating 12 and the coupling-out grating 13 , and is used to guide the image light beam coupled by the coupling-in grating 12 to the coupling-out grating 13 .

[0080] Figure 5 and Figure 6 All of them are schematic diagrams of grating arrangement in a head-up display device provided in an embodiment of the present application. Figure 5-Figure 6, the coupling-in grating 12 and the folding grating 14 are aligned in the center of the Y direction, and the folding grating 14 and the coupling-out grating 13 are aligned in the center of the X direction. The coupling-in grating 12 is used to couple the image light beam collimated by the optical machine 20 into the optical waveguide body 11 for total reflection transmission. When the optical waveguide body 11 transmits the image light beam to the folding grating 14 through total reflection, the image light beam is divided into two parts, one part continues to be transmitted through total reflection along the Y direction to achieve light expansion in the Y direction (pupil expansion in the Y direction), and the other part is transmitted through total reflection along the direction of the coupling-out grating 13 in the X direction. After the image light beam is transmitted to the coupling-out grating 13, it is coupled out by the coupling-out grating 13, and enters the human eye after being reflected by the windshield 40 to form an image on the retina.

[0081] When the periods of the coupling-in grating 12 and the coupling-out grating 13 are the same, the sum of the grating vectors of the coupling-in grating 12, the coupling-out grating 13 and the folding grating 14 is 0. Figure 5-Figure 6 As shown, the grating lines of the coupling-in grating 12 are parallel to the X-axis, the grating lines of the coupling-out grating 13 are parallel to the Y-axis, and the angle θ between the line direction of the folding grating 14 and the horizontal X-axis is 45°.

[0082] Figure 7 This is another schematic diagram of the basic components of the head-up display device provided in the embodiment of the present application. Figure 7 In some feasible implementations, the number of the optical waveguides 10 is two, one of the two optical waveguides 10 is the first optical waveguide 110 , and the other is the second optical waveguide 120 .

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

[0084] The outcoupling region 10b on the first optical waveguide 110 is a near-field outcoupling region 10b1, and the outcoupling region 10b on the second optical waveguide 120 is a far-field outcoupling region 10b2. The incoupling region 10a on the first optical waveguide 110 is used to couple in the first image beam, and the incoupling 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 outcoupling area 10b on the first optical waveguide 110 is set as a near-view outcoupling area 10b1, and the outcoupling area 10b on the second optical waveguide 120 is set as a far-view outcoupling area 10b2. The second image light beam emitted from the far-view outcoupling area 10b2 generates a second image. The near-view outcoupling area 10b1 is provided with a corresponding first lens unit 31, and the focal length of the first image light beam emitted from the near-view outcoupling area 10b1 is reduced by the first lens unit 31 to generate a first image. The depth of field of the first image after the focal length is reduced by the first lens unit 31 is smaller than the depth of field of the second image, so that the image light beam emitted by the optical machine 20 can present two focal planes with different depths of field after finally passing through the windshield 40 and reflecting to the position where the eyes of the driver in the car are located. The design of dual focal planes is realized by setting the first lens unit 31 at the near-view outcoupling area 10b1, which can not only simplify the volume of the head-up display device, but also reduce the cost of realizing dual focal planes. There are two optical waveguides 10 arranged in a stacked manner, which facilitates flexible design of the head-up display device, saves space, shares one optical engine 20 , and reduces costs.

[0087] Figure 8 This is another basic device structure diagram of a head-up display device provided in an embodiment of the present application. For details, please refer to Figure 8 The first optical waveguide 110 includes: a first optical waveguide body 111, a first coupling-in grating 112 and a first coupling-out grating 113, and the second optical waveguide 120 includes: a second optical waveguide body 121, a second coupling-in grating 122 and a second coupling-out grating 123.

[0088] The first coupling grating 112 is integrated in the coupling region 10a of the first optical waveguide body 111, and is used to couple the first image light beam emitted by the optical machine 20 into the first optical waveguide body 111. The first optical waveguide body 111 is used to totally reflect the first image light beam coupled by the first coupling grating 112 to the near-field coupling-out region 10b1. The first coupling-out grating 113 is integrated in the near-field coupling-out region 10b1 of the first optical waveguide body 111, and is used to couple out the first image light beam in the first optical waveguide body 111.

[0089] The second coupling grating 122 is integrated in the coupling region 10a of the second optical waveguide body 121, and is used to couple the second image light beam emitted by the optical machine 20 into the second optical waveguide body 121. The second optical waveguide body 121 is used to totally reflect the second image light beam coupled by the second coupling grating 122 to the distant coupling region 10b2. The second coupling grating 123 is integrated in the distant coupling region 10b2 of the second optical waveguide body 121, and is used to couple the second image light beam in the second optical waveguide body 121 out.

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

[0091] The first coupling-in grating 112 and the first coupling-out grating 113 may be on either the upper side or the lower side of the first optical waveguide body 111, and the second coupling-in grating 122 and the second coupling-out grating 123 may be on either the upper side or the lower side of the second optical waveguide body 121. The first coupling-in grating 112, the first coupling-out grating 113, the second coupling-in grating 122 and the second coupling-out grating 123 are all any one of a transmission grating and a reflection grating, and the type of the grating is determined by specifically combining the position of the grating and the method of transmitting the image light beam.

[0092] For example, Figure 8 The optical machine 20 is located at the lower side of the first optical waveguide body 111. The first coupling grating 112 is located at the lower side of the first optical waveguide body 111, and couples the first image light beam emitted by the optical machine 20 into the first optical waveguide body 111 by transmission, so the first coupling grating 112 is a transmission grating. The grating types of the first coupling grating 113, the second coupling grating 122 and the second coupling grating 123 are determined in the same way, so they are not analyzed again. Figure 8 The grating types of the first outcoupling grating 113, the second incoupling grating 122 and the second outcoupling grating 123 are shown in FIG.

[0093] The second image beam corresponds to a second image at a farther 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 correspondingly make the brightness of the virtual image surface produced by the second image larger, so that the driver in the car can obtain the information transmitted by the second image in time to improve driving safety.

[0094] In some feasible embodiments, the brightness of the first image beam emitted by the optical machine 20 is lower than the brightness of the second image beam. Alternatively, the grating height of the first coupling grating 112 is lower than the grating height of the second coupling grating 122, so that the coupling efficiency of the second coupling grating 122 to the second image beam is relatively higher, so that the brightness of the second image beam is higher than the brightness of the first image beam. Alternatively, the grating height of the first coupling grating 113 is lower than the grating height of the second coupling grating 123, so that the coupling efficiency of the second coupling grating 123 to the second image beam is relatively higher, so that the brightness of the second image beam is higher than the brightness of the first image beam. Alternatively, a filter is provided at any one of the light exiting side of the first coupling grating 113, the light entering side of the first lens unit 31, and the light exiting side of the first lens unit 31, and the brightness of the first image beam or the first image is reduced by the filter, so that the brightness of the first image is lower than the brightness of the second image.

[0095] See also Figure 8 In some feasible implementations, the focus 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 outcoupling area 10b2. The second lens unit 32 is used to reduce the focal length of the second image light beam emitted from the distant outcoupling 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 far-field outcoupling area 10b2 is smaller than the degree to which the first lens unit 31 reduces the focal length of the first image beam emitted from the near-field outcoupling area 10b1.

[0097] The focal length of the second image light beam coupled out of the distant out-coupling area 10b2 is reduced by the second lens unit 32, and the degree to which the focal length of the second image light beam emitted from the distant out-coupling area 10b2 is reduced by the second lens unit 32 is less than the degree to which the focal length of the first image light beam emitted from the near-field out-coupling area 10b1 is reduced by the first lens unit 31, 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 cooperate to facilitate the generation of two focal planes with different depths of field or different imaging distances according to imaging requirements, which facilitates the precise design of the imaging of the head-up display device. The focal length adjustment layer 30 adopts the combined design of the first lens unit 31 and the second lens unit 32 to achieve dual focal plane adjustment, which has a simple structure, a small size and a low cost.

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

[0099] Fig. 9 It is a schematic diagram of imaging of a head-up display device provided in an embodiment of the present application. By using the head-up display device in the above embodiment disclosed in the present application, a first image and a second image with different field of view angles, different depths of field and different brightness can be seen at the eye box (that is, the position of the driver's eyes in the car).

[0100] The head-up display device of the present application discloses a dual-focal-plane AR HUD design based on an optical waveguide, which can realize a dual-focal-plane AR HUD by using a set of optical machines 20 and partitioning through a focal length adjustment layer 30. Compared with the existing mainstream dual-focal-plane AR HUD based on a free-form surface reflector solution, the structure is simplified and the cost is reduced. In addition, the AR HUD display is realized by using an optical waveguide 10, which can realize a small volume and a large FOV display, and improve the problem of the mutual restriction between the volume and FOV of the existing AR HUD based on an off-axis free-form surface reflector.

[0101] An embodiment of the present application further provides a vehicle, 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 described in the above embodiment.

[0102] Since the head-up display device described in the above embodiment has the advantages of simple structure and small size, a vehicle using the head-up display device described in the above embodiment 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] The head-up display device in the embodiment of the present application is used as a driving assistance system in a vehicle. A set of optical machines 20 can be used to achieve a dual focal plane design through a focal length adjustment layer 30, effectively reducing the cost of the driving assistance system in the vehicle, and thus reducing the cost of the vehicle.

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

[0105] In some feasible embodiments, the cockpit has a windshield 40 , the focus adjustment layer 30 , the optical waveguide 10 and the windshield 40 are distributed at intervals, 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 focus adjustment layer 30 and the optical waveguide 10 are spaced apart to avoid the angle deviation of the light when the two are attached to each other during transmission in the optical waveguide 10, thereby ensuring the accuracy of light transmission. The focus adjustment layer 30 and the windshield 40 are spaced apart to avoid interference with the driver's sight in the cockpit when the two are attached to each other, thereby ensuring the safety of driving a vehicle. The spacing between the focus adjustment layer 30 and the optical waveguide 10 is smaller than the spacing between the focus adjustment layer 30 and the windshield 40, which helps to make the structure of the head-up display device compact, thereby saving space in the cockpit.

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

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

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

Claims

1. A head-up display device, characterized in that: include: Optical waveguide, optical machine and focus adjustment layer; The optical waveguide has an incoupling region and an outcoupling region; The optical machine is located at one side of the optical waveguide, and the light output direction of the optical machine is toward the coupling-in area; The focus adjustment layer is located between the optical waveguide and the windshield, and the orthographic projection of the focus adjustment layer on the optical waveguide overlaps with the outcoupling region; Among them, the optical machine is used to emit an image light beam toward the coupling-in area; the optical waveguide is used to transmit the image light beam from the coupling-in area to the coupling-out area, and guide it to the focus adjustment layer through the coupling-out area; the focus adjustment layer is used to adjust the focus of at least part of the image light beam emitted from the coupling-out area to produce a first image and a second image with different depth of field.

2. The head-up display device according to claim 1, characterized in that: The outcoupling area includes: a near-view outcoupling area and a far-view outcoupling area; The focal length adjustment layer comprises a first lens unit, the orthographic projection of the first lens unit on the optical waveguide overlaps with the near-view outcoupling area, and the first lens unit is used to reduce the focal length of the image light beam emitted from the near-view outcoupling area to generate a first image; The image light beam emitted from the long-range outcoupling area generates the second image, and the depth of field of the first image is smaller than the depth of field of the second image.

3. The head-up display device according to claim 2, characterized in that: The focal length adjustment layer further comprises a second lens unit, the orthographic projection of the second lens unit on the optical waveguide overlaps with the distant outcoupling area, and the second lens unit is used to reduce the focal length of the image light beam emitted from the distant outcoupling area to generate the second image; The extent to which the second lens unit reduces the focal length of the image light beam emitted from the far-view out-coupling area is less than the extent to which the first lens unit reduces the focal length of the image light beam emitted from the near-view out-coupling area.

4. The head-up display device according to claim 2, characterized in that: The image beam emitted by the optical machine includes: a first image beam and a second image beam, wherein the first image beam and the second image beam have different viewing angles; The first image light beam is used to be transmitted to the near-view outcoupling area through the optical waveguide, and the second image light beam is used to be transmitted to the far-view outcoupling area through the optical waveguide.

5. The head-up display device according to claim 4, characterized in that: The number of the optical waveguides is two, one of the two optical waveguides is a first optical waveguide, and the other is a second optical waveguide; The first optical waveguide and the second optical waveguide are stacked and arranged in a light emitting direction of the optical machine, and the first optical waveguide is closer to the optical machine than the second optical waveguide; The outcoupling area on the first optical waveguide is the near-view outcoupling area, and the outcoupling area on the second optical waveguide is the far-view outcoupling area; and the incoupling area on the first optical waveguide is used for coupling in the first image light beam, and the incoupling area on the second optical waveguide is used for coupling in the second image light beam; Wherein, the first lens unit is located between the first optical waveguide and the second optical waveguide.

6. The head-up display device according to claim 4 or 5, characterized in that: The optical waveguide comprises: an optical waveguide body, an incoupling grating and an outcoupling grating; the optical waveguide body has the incoupling region and the outcoupling region, the incoupling grating is located in the incoupling region, and the outcoupling grating is located in the outcoupling region.

7. The head-up display device according to claim 6, characterized in that: The brightness of the first image light beam emitted by the optical machine is smaller than the brightness of the second image light beam; Alternatively, the height of the outcoupling grating at the near-view outcoupling area is smaller than the height of the outcoupling grating at the far-view outcoupling area, so that the brightness of the first image light beam after being coupled out by the near-view outcoupling area is smaller than the brightness of the second image light beam after being coupled out by the near-view outcoupling area.

8. The head-up display device according to claim 6, characterized in that: The optical waveguide further comprises: a folding grating; The folding grating is located between the coupling-in grating and the coupling-out grating, and is used to guide the image light beam coupled by the coupling-in grating to the coupling-out grating.

9. A means of transport, 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 8.

10. The vehicle according to claim 9, characterized in that: The cockpit has 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.

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