A head-up display device

Abstract

The application discloses a head-up display device, which comprises an image source for emitting an image light beam, a diffractive optical waveguide, a focusing device and a windshield glass, wherein the diffractive optical waveguide comprises a waveguide substrate and a coupling-in structure and a coupling-out structure located on one side of the waveguide substrate, the coupling-in structure is used for coupling the image light beam into the waveguide substrate, the image light beam propagates in the waveguide substrate by total reflection to the coupling-out structure, and the coupling-out structure is used for coupling the image light beam out of the waveguide substrate; the focusing device is located on an exit light path of the coupling-out structure, and the coupling-out light beams of different field of view regions are modulated by the focusing device and then imaged at at least two positions with different distances from the windshield glass after being reflected by the windshield glass. The technical scheme of the embodiment of the application can image at different depths of the windshield glass, so that the driver can see virtual images at different depths in front of the windshield glass, the device has a small volume and saves space, and potential traffic accidents can be reduced to ensure driving safety.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more particularly to a head-up display device. Background Technology

[0002] Augmented reality (AR) is a technology that blends the real world with virtual information. AR display systems typically include a micro-projector and an optical display screen. Pixels on the micro-display screen are projected onto the viewer's eyes through the optical display screen, allowing the user to see the real world through the optical display screen.

[0003] A head-up display (HUD) is a visual driver assistance system that provides drivers with crucial driver assistance information. It projects driving information into a virtual image and displays it at a certain distance in front of the driver, allowing the driver to obtain information such as vehicle speed, fuel level, and real-time navigation while looking straight ahead.

[0004] However, traditional W-HUDs use a multi-reflection optical system, resulting in a large head-up display that takes up too much space when placed at the front of the vehicle. Summary of the Invention

[0005] This invention provides a head-up display (HUD) device. The device couples an image beam into a waveguide substrate via a coupling structure. The image beam propagates through total internal reflection within the waveguide substrate to a coupling structure, which then couples the image beam out of the waveguide substrate. The coupled beams from different field-of-view regions are modulated by a focusing device and reflected by the windshield, forming images at at least two positions at different distances from the windshield. The images have continuous focal points, allowing the driver to see virtual images of varying depths in front of the windshield. Based on the optical waveguide principle, the HUD provided by this invention features a large field of view and a small size. Furthermore, the waveguide substrate is thin, significantly reducing the overall size of the HUD and solving the problem of excessively large devices occupying too much space in the front of the vehicle due to the use of multiple reflection optical systems in existing technologies.

[0006] According to one aspect of the present invention, a head-up display device is provided, comprising:

[0007] Image source, used to emit an image beam;

[0008] A diffractive waveguide, comprising a waveguide substrate and a coupling-in structure and a coupling-out structure located on at least one side of the waveguide substrate, wherein the coupling-in structure is used to couple the image beam into the waveguide substrate, the image beam propagates through the waveguide substrate by total internal reflection to the coupling-out structure, and the coupling-out structure is used to couple the image beam out of the waveguide substrate;

[0009] A focusing device is located on the output light path of the coupling structure. The coupled light beams from different field areas are modulated by the focusing device and reflected by the windshield, and then imaged at at least two positions at different distances from the windshield.

[0010] Optionally, the focusing device includes an imaging lens group with positive optical power and a collimating lens group with optical power, wherein the imaging lens group is located on the side of the collimating lens group closer to the diffractive waveguide.

[0011] Optionally, the imaging lens group includes at least one lens, which may be a spherical lens, a secondary higher-order aspherical lens, or a freeform surface lens.

[0012] Optionally, the collimating lens group includes at least one microlens array, at least one Fresnel lens array, or a freeform lens.

[0013] Optionally, at least one parameter of the collimating lens group is gradually changed along at least one direction perpendicular to the optical axis of the focusing device.

[0014] Optionally, the optical power of the collimating lens group is reduced along the direction closer to the windshield.

[0015] Optionally, the image source includes a first image source and a second image source, and the diffractive waveguide includes a first diffractive waveguide and a second diffractive waveguide;

[0016] The first image source is used to emit a left-eye image beam, which is transmitted through the first diffractive waveguide, modulated by the focusing device, and reflected by the windshield to form a left-eye image.

[0017] The second image source is used to emit a right-eye image beam, which is transmitted through the second diffractive waveguide, modulated by the focusing device, and reflected by the windshield to form a right-eye image.

[0018] Optionally, the focusing device includes a first focusing device and a second focusing device, wherein the first focusing device is used to modulate the left eye image beam and the second focusing device is used to modulate the right eye image beam.

[0019] Optionally, the diffractive waveguide further includes a pupil expanding structure, which includes a first pupil expanding structure and a second pupil expanding structure, and the coupling structure includes a first coupling structure and a second coupling structure;

[0020] The image beam includes a left-eye image beam and a right-eye image beam. The left-eye image beam is coupled into the coupling structure and then passes through the first pupil dilation structure and the first coupling structure before being output. The right-eye image beam is coupled into the coupling structure and then passes through the second pupil dilation structure and the second coupling structure before being output.

[0021] Optionally, the first pupil dilator structure and the second pupil dilator structure are located on the first side of the coupling structure, and the first coupling out structure and the second coupling out structure are located on the first side of the coupling structure; or

[0022] The coupling structure is located between the first pupil dilator structure and the second pupil dilator structure, and the coupling structure is located between the first coupling outlet structure and the second coupling outlet structure. The first pupil dilator structure and the first coupling outlet structure are located on the same side of the coupling structure.

[0023] Optionally, both the pupil expansion structure and the coupling structure include a grating, and the depth of the grating increases along the direction of beam transmission.

[0024] Optionally, the diffractive waveguide may further include a reflective layer located in the coupling structure and / or the coupling structure.

[0025] Optionally, the coupling structure is located on the side of the waveguide substrate away from or close to the image source, and the reflective layer is located on the opposite side of the coupling structure; and / or

[0026] The coupling structure is located on the side of the waveguide substrate away from the image source, and the reflective layer is located on the side of the waveguide substrate closer to the image source.

[0027] Optionally, the diffractive waveguide includes an input one-dimensional grating and an output two-dimensional grating, or the diffractive waveguide includes an input one-dimensional grating, a pupil-expanding one-dimensional grating, and an output one-dimensional grating.

[0028] Optionally, the diffractive waveguide includes at least one of a straight-tooth grating, a helical-tooth grating, or a blazed grating.

[0029] Optionally, an infrared reflective layer or an infrared absorbing layer is provided on one side of the windshield.

[0030] The present invention provides a head-up display device that couples an image beam into a waveguide substrate through a coupling structure. The image beam propagates through the waveguide substrate by total internal reflection to a coupling structure, which couples the image beam out of the waveguide substrate. The coupled beams from different fields of view are modulated by a focusing device and reflected by the windshield, forming images at at least two positions at different distances from the windshield. The images have continuous focal points, so the driver can see virtual images of different depths in front of the windshield.

[0031] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a head-up display device provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the focusing device of a head-up display device provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the structure of another head-up display device provided in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of another head-up display device provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of a diffractive waveguide for a head-up display device provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the structure of a diffractive waveguide for another head-up display device provided in an embodiment of the present invention;

[0039] Figure 7 A schematic diagram of the structure of a diffractive optical waveguide for another head-up display device provided in an embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the structure of a diffractive waveguide for another head-up display device provided in an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] Figure 1 This is a schematic diagram of the structure of a head-up display device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the device includes: an image source 100, a diffractive waveguide 200, and a focusing device 300.

[0044] See Figure 1 An image source 100 is used to emit an image beam; a diffraction waveguide 200 includes a waveguide substrate 210 and a coupling structure 220 and a coupling structure 230 located on at least one side of the waveguide substrate 210. The coupling structure 220 couples the image beam into the waveguide substrate 210, and the image beam propagates through total internal reflection in the waveguide substrate 210 to the coupling structure 230. The coupling structure 230 couples the image beam out of the waveguide substrate 210. A focusing device 300 is located on the output optical path of the coupling structure 230. The coupled beams from different field-of-view regions are modulated by the focusing device 300 and reflected by the windshield 400, and then imaged at at least two positions at different distances from the windshield 400.

[0045] The image source 100 includes, but is not limited to, an optical engine. The number of image sources 100 can be adjusted according to the specific structure of the head-up display device, for example, two. The diffractive waveguide 200 includes, but is not limited to, a volume holographic waveguide or a surface relief grating waveguide. The material of the diffractive waveguide 200 can be glass, for example, 1.5-2.0 glass with a thickness of 2mm-10mm. The refractive index of the transmission medium inside the waveguide substrate 210 is greater than that of the surrounding medium. When the incident angle in the waveguide is greater than the critical angle for total internal reflection, light can undergo total internal reflection within the waveguide, transmitting without loss. The coupling structure 220 is located in the light-emitting direction of the image source 100 and includes, but is not limited to, coupling the image beam into the waveguide substrate through diffraction. Inside the base 210; the focusing device 300 includes, but is not limited to, an imaging lens group and a collimating lens group, used to modulate the light beams emitted from different regions of the coupling structure 230 and make them produce different angles. The focusing device 300 is located on the outgoing light path of the diffractive waveguide 200. The specific position is set on the basis of ensuring that all coupled light beams can enter the focusing device, for example, the distance from the coupling structure 230 is 3-30mm; the dimensions of the coupling structure 220 and the coupling structure 230 are adjusted according to the specifications of the diffractive waveguide 200.

[0046] Specifically, image source 100 emits an image beam, which propagates to coupling structure 220. Coupling structure 220 couples the image beam into waveguide substrate 210. Further, the coupled beam undergoes total internal reflection within waveguide substrate 210 and propagates to coupling structure 230. Coupling structure 230 couples the beam out of diffraction waveguide 200. Focusing device 300 is positioned corresponding to coupling structure 230, ensuring that all coupled beams can enter focusing device 300, avoiding image ghosting that interferes with the main image. The coupled beam is a parallel beam, modulated by focusing device 300, causing different angles in different areas of the coupled beam. After reflection by windshield 400, it enters the receiving area of ​​the human eye. Figure 1 As shown at L1 and L2, because different field of view angles have different included angles, their backward extensions intersect at different positions in space, thus allowing the driver to see virtual images of different depths in front of the windshield.

[0047] The technical solution of this invention couples an image beam into a waveguide substrate through a coupling structure. The image beam propagates through total internal reflection in the waveguide substrate to a coupling structure, which couples the image beam out of the waveguide substrate. The coupled beams from different fields of view are modulated by a focusing device and reflected by the windshield, forming images at at least two positions at different distances from the windshield. The images have continuous focal points, so the driver can see virtual images of different depths in front of the windshield.

[0048] Based on the above embodiments, this embodiment of the invention provides a specific structure for an optional focusing device 300. Figure 2This is a schematic diagram of the focusing device of a head-up display device provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the focusing device 300 includes an imaging lens 310 with positive optical power and a collimating lens group 320 with optical power, wherein the imaging lens group 310 is located on the side of the collimating lens group 320 close to the diffractive waveguide 200.

[0049] The imaging lens group 310 has a positive optical power and is used to converge the coupled beam from the diffractive waveguide 200. The optical power of the imaging lens group 310 is adjusted to ensure that the converged beam can be incident on the collimating lens group 320, and is not limited here. The collimating lens group 320 can have a positive or negative optical power, and is not limited here. The collimating lens group 320 is used to adjust the beam emitted from the imaging lens group 310, thereby giving the beam emitted from the focusing device 300 a smaller divergence angle. The divergence angle is adjusted according to actual needs by adjusting the specifications of the collimating lens group 320, thereby controlling the imaging position. The distance between the imaging lens group 310 and the collimating lens group 320 is adjusted according to the specifications of the imaging lens group 310 and the collimating lens group 320, such as the focal length of the collimating lens group 320.

[0050] Specifically, the image source 100 emits an image beam, which propagates to the coupling structure 220. The coupling structure 220 couples the image beam into the waveguide substrate 210. Further, the coupled beam undergoes total internal reflection within the waveguide substrate 210 and propagates to the coupling structure 230. The coupling structure 230 couples the beam out of the diffraction waveguide 200. The focusing device 300 is positioned corresponding to the coupling structure 230 to ensure that all coupled beams can enter the focusing device 300, avoiding image ghosting that interferes with the main image. The output beam consists of multiple sets of parallel beams, each corresponding to a field of view or a range of field of view. After passing through the imaging lens group 310 with positive optical power, the parallel beams converge at different positions of the collimating lens group 320. The collimating lens group 320 focuses according to the imaging position requirements of each set of parallel beams. The output beam of each set of parallel beams after passing through the focusing device 300 has a certain divergence angle. By controlling the divergence angle, the output beam of the focusing device 300 enters the receiving area of ​​the human eye after being reflected by the windshield 400, thereby improving the imaging accuracy at different positions.

[0051] Optionally, the imaging lens group 310 includes at least one lens, which may be a spherical lens, a secondary higher-order aspherical lens, or a freeform surface lens.

[0052] The imaging lens group 310 includes lenses used to converge the light beam from the diffractive waveguide 200. Specifically, these lenses can be spherical lenses, secondary higher-order aspherical lenses, or freeform surface lenses, which have high focusing accuracy and can control the imaging point more precisely.

[0053] Specifically, the image beam is coupled out through the diffraction waveguide 200 and incident on the imaging lens group 310. After being modulated by a spherical lens, a secondary higher-order aspherical lens or a freeform surface lens, the beam converges at the collimating lens group 320 with higher accuracy. Then, after passing through the collimating lens group 320, it is incident on the windshield 400. After being reflected by the windshield 400, it enters the receiving area of ​​the human eye and is imaged at different positions.

[0054] Optionally, the collimating lens group 320 includes at least one microlens array, at least one Fresnel lens array, or a freeform lens.

[0055] The collimating lens group 320 includes lenses or lens arrays used to modulate the beam emitted from the imaging lens group 310. Microlens arrays, Fresnel lens arrays, and freeform lenses can make the beam emitted from the lens array more uniform and more accurate.

[0056] Specifically, the image beam is coupled out through the diffraction waveguide 200 and incident on the imaging lens group 310. After being modulated by the imaging lens group 310, it is incident on the collimating lens group 320. After being modulated by at least one microlens array, at least one Fresnel lens array or freeform lens, the beam emitted from the collimating lens group 320 has a certain angle, and is then reflected by the windshield 400 and incident on the receiving area of ​​the human eye, thereby improving the accuracy of imaging at different positions.

[0057] It should be noted that the coupled beams of the coupling structure are parallel beams with different field of view angles. In order to image the beams with different field of view angles at different distances from the windshield, this application uses an imaging lens group to pre-image the parallel beams with different field of view angles at different positions. Then, collimating lenses are set at each pre-image position of the parallel beams with different field of view angles, and these collimating lenses form a collimating lens group. Although it is called a collimating lens group, the beam is not strictly collimated after passing through it, because the collimated beam is imaged at infinity after entering the human eye, and there is no distance information. If we want to achieve imaging at multiple positions with different distances from the windshield, the beam needs to be a divergent beam after exiting the collimating lens group, with a small divergence angle. By controlling this divergence angle, we can control the different imaging positions. Since multiple imaging points are achieved by imaging the beams with different field of view angles separately, the optical power of the collimating lens group 310 can be set to vary, and the optical power of the collimating lenses acting on the beams with different field of view angles is different.

[0058] Optionally, at least one parameter of the collimating lens group 310 is gradually changed along at least one direction perpendicular to the optical axis of the focusing device 300.

[0059] The parameters that vary gradually include, but are not limited to, height, lens aperture, and radius of curvature.

[0060] Specifically, at least one parameter of the collimating lens group 310 gradually changes along at least one direction perpendicular to the optical axis of the focusing device 300, thereby enabling the light beam emitted from the focusing device 300 to obtain a continuous imaging distance after being reflected by the windshield 400, so that the human eye can see virtual images of different depths in front of the windshield 400.

[0061] Optionally, the optical power of the collimating lens group 310 is reduced along the direction closer to the windshield 400.

[0062] Specifically, along the direction close to the windshield 400, the optical power of the collimating lens group 310 decreases, so that the human eye can see virtual images of different depths on the windshield 400.

[0063] In summary, the technical solution of the present invention, through further refinement, improves the image imaging accuracy of the head-up display device, enabling the human eye to see virtual images of different depths.

[0064] Optionally, based on the above embodiments, this embodiment of the invention provides an optional head-up display device structure. Figure 3 This is a schematic diagram of another head-up display device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the image source 100 includes a first image source 101 and a second image source 102, and the diffraction waveguide 200 includes a first diffraction waveguide 201 and a second diffraction waveguide 202.

[0065] See Figure 3 The first image source 101 is used to emit a left-eye image beam. The left-eye image beam is transmitted through the first diffraction waveguide 201, modulated by the focusing device 300, and reflected by the windshield 400 to form a left-eye image. The second image source 102 is used to emit a right-eye image beam. The right-eye image beam is transmitted through the second diffraction waveguide 202, modulated by the focusing device 300, and reflected by the windshield 400 to form a right-eye image.

[0066] The first image source 101 and the second image source 102 include, but are not limited to, an optomechanical system. The optical axes of the first image source 101 and the second image source 102 can have a certain angle and opposite deflection directions, for example, an angle between 0 and 1°. The first diffraction waveguide 201 is positioned corresponding to the first image source 101, and the second diffraction waveguide 202 is positioned corresponding to the second image source 102. For example, the two image sources and the diffraction waveguides are arranged along a direction parallel to the windshield 400, and the two diffraction waveguides are parallel. The image content of the left-eye image beam and the right-eye image beam can be the same or different.

[0067] Specifically, the first image source 101 emits a left-eye image, which is transmitted through the first diffractive waveguide 201, modulated by the focusing device 300, and reflected by the windshield 400 to form the left-eye image. The second image source 102 emits a right-eye image beam, which is transmitted through the second diffractive waveguide 202, modulated by the focusing device 300, and reflected by the windshield 400 to form the right-eye image. The optical axes of the first image source 101 and the second image source 102 have a certain angle, so that the optical axes of the image beams coupled from the left and right eyes have a certain angle. This allows the image beams coupled from the left and right eyes to be combined after being focused by the focusing device 300 and reflected by the windshield 400, forming a three-dimensional virtual image. The left and right eye recognition images are emitted from corresponding image sources, and then diffracted and transmitted by corresponding diffractive waveguides, forming two separate human eye recognition areas. This increases the effective utilization area ratio of the diffractive waveguides, thereby effectively reducing the area of ​​the diffractive waveguides.

[0068] Optional, Figure 4 This is a schematic diagram of another head-up display device provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the focusing device 300 includes a first focusing device 301 and a second focusing device 302. The first focusing device 301 is used to modulate the left eye image beam, and the second focusing device 302 is used to modulate the right eye image beam.

[0069] The first focusing device 301 is located on the output optical path of the first diffractive waveguide 201, and the second focusing device 302 is located on the output optical path of the second diffractive waveguide 202. The specific positions of the first focusing device 301 and the second focusing device 302, such as the distance between the two focusing devices and the two diffractive waveguides respectively, and the angle between the optical axes of the two focusing devices, can be set according to the actual situation and are not limited here. For example, they can be set according to the effective area width, coupling width, and field of view of the diffractive waveguides. The optical axes of the two focusing devices have an angle between 0 and 2°, and the two focusing devices deflect in opposite directions.

[0070] Specifically, the left-eye image beam is coupled out through the first diffractive waveguide 201 and emitted to the first focusing device 301. The emitted beam is modulated and reflected by the windshield 400 to form the left-eye image. The right-eye image beam is coupled out through the second diffractive waveguide 202 and emitted to the second focusing device 302. The emitted beam is modulated and reflected by the windshield 400 to form the right-eye image. The left and right eye images are modulated by their respective focusing devices to further improve the image modulation accuracy, thereby improving the imaging accuracy at different positions.

[0071] In summary, the technical solution of this invention, by setting corresponding optical path structures for left and right eye imaging, divides the imaging at the human eye into two separate human eye imaging regions, which improves imaging accuracy and effectively reduces the area of ​​the diffraction waveguide. Furthermore, by adjusting the optical components (optical mechanism or focusing device, etc.) on the optical path, the left and right eye imaging can be further formed into a three-dimensional virtual image.

[0072] Based on the above embodiments, this invention provides an optional specific structure for a diffractive waveguide. Figure 5 This is a schematic diagram of the structure of a diffractive waveguide for a head-up display device provided in an embodiment of the present invention, as shown below. Figure 5 As shown, the diffractive waveguide 200 also includes a pupil expanding structure 240, which includes a first pupil expanding structure 241 and a second pupil expanding structure 242, and a coupling structure 230 includes a first coupling structure 231 and a second coupling structure 232.

[0073] See Figure 5 The image beam includes a left-eye image beam and a right-eye image beam. The left-eye image beam is coupled into the coupling structure 220 and then passes through the first pupil dilation structure 241 and the first coupling structure 231 before being output. The right-eye image beam is coupled into the coupling structure 220 and then passes through the second pupil dilation structure 242 and the second coupling structure 232 before being output.

[0074] The first pupil expanding structure 241 and the second pupil expanding structure 242 are located inside the diffraction waveguide 200 and are arranged side by side along the optical path of the coupled beam into the diffraction waveguide 200. The first coupling out structure 231 is located on the output optical path of the first pupil expanding structure 241 and the second coupling out structure 232 is located on the output optical path of the second pupil expanding structure 242.

[0075] Specifically, the left-eye image beam enters through the coupling structure 220, passes through the first pupil dilator 241 and the first output structure 231 in sequence, and is then output. The right-eye image beam enters through the coupling structure 220, passes through the second pupil dilator 242 and the second output structure 232 in sequence, and is then output. The left and right eye images are output through the corresponding pupil dilator and output structures, respectively, thus forming two separate human eye imaging regions. After merging, they form a three-dimensional virtual image.

[0076] It should be noted that, Figure 5 Only one specific structure of the diffractive waveguide that can be implemented is shown. The positions of the coupling structure 220, the first pupil structure 241, and the second pupil structure 242 can be adjusted by adjusting the position of the coupling structure 220.

[0077] Optional, Figure 6 This is a schematic diagram of the diffractive waveguide structure of another head-up display device provided in an embodiment of the present invention. (Continue reading...) Figure 5The first pupil dilator structure 241 and the second pupil dilator structure 242 are located on the first side of the coupling structure 220, and the first coupling structure 231 and the second coupling structure 232 are located on the first side of the coupling structure 220.

[0078] Or, such as Figure 6 As shown, the coupling structure 220 is located between the first pupil dilator structure 241 and the second pupil dilator structure 242, and the coupling structure 220 is located between the first coupling out structure 231 and the second coupling out structure 232. The first pupil dilator structure 241 and the first coupling out structure 231 are located on the same side of the coupling structure 220.

[0079] Among them, the positive and negative first stages of the coupling structure 220 are coupled into the corresponding image beams of the left and right eyes, respectively.

[0080] Specifically, the left eye image beam is coupled into the coupling structure 220 and then passes through the first pupil dilation structure 241 and the first coupling out structure 231 before being output. The right eye image beam is coupled into the coupling structure 220 and then passes through the second pupil dilation structure 242 and the second coupling out structure 232 before being output. After the images are combined, a three-dimensional virtual image is formed.

[0081] Optionally, both the pupil expansion structure and the coupling structure include gratings, with the depth of the gratings increasing along the direction of beam propagation.

[0082] Specifically, the image beam is coupled into the pupil expansion structure through the coupling structure 220. Along the direction of beam transmission, the depth of the grating increases, making the beam brightness in the coupling area more uniform and improving the consistency of the brightness of the left and right eye images.

[0083] It should be noted that when the pupil expansion structure is divided into two regions, there is a gap between the first pupil expansion structure 241 and the second pupil expansion structure 242. The gap between the two regions can be set according to the specifications of the diffraction waveguide 200, for example, 10mm-40mm.

[0084] Specifically, when the two regions are separated, the intermediate region no longer generates a coupled beam, which allows the beam reaching the other coupled region to have more remaining energy, effectively improving the brightness consistency of the left and right eye imaging.

[0085] It should be noted that the optical axes of the left and right eye-coupled beams formed by the same image source 100 are parallel. At this time, the focusing device 300 needs to have additional optical axis adjustment function so that the optical axes of the left and right eye-coupled image beams have a certain angle. This allows the left and right eye-coupled image beams to be combined after being focused by the focusing device 300 and reflected by the windshield 400, forming a three-dimensional virtual image.

[0086] In summary, the technical solution of this invention, based on the above embodiments, further provides a specific structure of a diffractive waveguide, which further refines the internal structure of the diffractive waveguide into a coupling structure, a pupil expansion structure, a coupling output structure, and a waveguide substrate, thereby dividing the image at the human eye into two eye imaging regions, and forming a three-dimensional image through image merging.

[0087] Based on the above embodiments, this invention provides an optional diffractive waveguide structure that further reduces the loss of the light beam incident on the diffractive waveguide. Figure 7 This is a schematic diagram of the structure of a diffractive waveguide for another head-up display device provided in an embodiment of the present invention.

[0088] like Figure 7 As shown, the diffractive waveguide 200 also includes a reflective layer 203 located in the coupling structure 220 and / or the coupling structure 230.

[0089] The reflective layer 203 is used to reflect coupled-in and / or coupled-out beams that do not meet the total reflection condition of the waveguide substrate 210. The reflective layer 203 includes, but is not limited to, multilayer dielectric films or metal films, such as aluminum or silver. The operating wavelength and operating angle of the reflective layer 203 can be set according to the actual situation and are not limited here. The reflective layer 203 can be set in all or part of the bottom area of ​​the waveguide substrate 210 and are not limited here.

[0090] Specifically, such as Figure 7 As shown in b, the image beam is coupled into the waveguide substrate 210 via the coupling structure 220 and undergoes diffraction, generating multiple orders of diffracted light. The diffraction angles of some orders of diffracted light can satisfy the total internal reflection condition and continue to propagate within the waveguide substrate 210 through total internal reflection. However, the T0 order of some diffracted light at the coupling structure 220 cannot satisfy the total internal reflection condition and is wasted by passing through the waveguide substrate 210. By adding a reflective layer 203 at the coupling structure 220, the T0 order diffracted light is reflected and interacts with the coupling structure 220 again, thereby utilizing the reflected order and propagating in the waveguide substrate 210 together with the transmitted order, increasing the utilization rate of the image beam.

[0091] Furthermore, such as Figure 7 As shown in Figure a, the image beam coupled into the waveguide substrate 210 undergoes total internal reflection by the waveguide substrate 210 and diffracts at the coupling structure 230, producing a transmission-1st order (T) beam. -1 ) and Reflection-1 (R -1 The diffracted light typically uses only one order of transmission or reflection. A portion of the diffracted light is coupled out through the coupling structure 230 and enters the human eye, while the remaining portion is wasted by transmitting through the waveguide substrate 210. By adding a reflective layer 203 at the coupling structure 230, the reflection order R is increased. -1Outwards towards the human eye, thus simultaneously receiving T -1 and R -1 The energy of the coupled beam is now double that of the beam without a reflective layer.

[0092] It should be noted that the reflective layer 203 can be set in the coupling-in region and / or coupling-out region according to the actual situation.

[0093] In one embodiment, the operating wavelength of the reflective layer 203 corresponding to the coupling-out region is 440nm-650nm and the operating angle is 30°-80°; the operating wavelength of the reflective layer 203 corresponding to the coupling-in region is 440nm-650nm and the operating angle is 0-40°.

[0094] Optionally, the coupling structure 220 is located on the side of the waveguide substrate 210 away from or near the image source 100, and the reflective layer 203 is located on the opposite side of the coupling structure 220; and / or

[0095] The coupling structure 230 is located on the side of the waveguide substrate 210 away from the image source 100, and the reflective layer 203 is located on the side of the waveguide substrate 210 closer to the image source 100.

[0096] Specifically, the reflective layer 203 is located on the opposite side of the coupling structure 220, so that the diffracted light level that is coupled into the waveguide substrate 210 and cannot meet the total reflection condition of the waveguide substrate 210 is reflected by the reflective layer 203 and interacts with the coupling structure 220 again, thereby improving the utilization rate of the image beam.

[0097] The coupling structure 230 is located on the side of the waveguide substrate 210 away from the image source 100. The image beam undergoes total internal reflection within the waveguide substrate 210 to the coupling region, and then is coupled out through the coupling structure 230 to the diffracted light waveguide 200, and then propagates to the focusing device 300. The reflective layer 203 is located on the side of the waveguide substrate 210 closer to the image source 100, so that diffracted light levels that do not meet the total internal reflection condition of the waveguide substrate 210 are reflected to the coupling structure 230, and then coupled out toward the focusing device 300. Compared with the absence of the reflective layer 203, the energy of the beam emitted from the coupling structure 230 is doubled.

[0098] In summary, the technical solution of this invention, based on the above embodiments, further provides a specific structure for a diffractive waveguide by adding a reflective layer in the region where the coupling structure and / or coupling structure are located, thereby improving the utilization rate of the image beam.

[0099] Based on the above embodiments, this invention provides an optional specific structure for a diffractive waveguide. Figure 8 This is a schematic diagram of the structure of a diffractive waveguide for another head-up display device provided in an embodiment of the present invention.

[0100] like Figure 8 As shown in Figure a, the diffractive waveguide 200 includes an input one-dimensional grating 204 and an output two-dimensional grating 205, or, as... Figure 8 As shown in b, the diffractive waveguide 200 includes an input one-dimensional grating 204, a pupil-expanding one-dimensional grating 206, and an output one-dimensional grating 207.

[0101] Continue to refer to Figure 8 a. The image beam is coupled into the waveguide substrate 210 via the coupled one-dimensional grating 204. It propagates through the waveguide substrate 210 by total internal reflection to the coupled two-dimensional grating 205. The left-eye image beam is coupled out through the coupled two-dimensional grating 205 to form the left-eye image, and the right-eye image beam is coupled out through the coupled two-dimensional grating 205 to form the right-eye image. The three-dimensional virtual image is formed by combining the images.

[0102] Continue to refer to Figure 8 b. The image beam is coupled into the waveguide substrate 210 via the coupled one-dimensional grating 204, and then into the pupil-expanding one-dimensional grating 206 to form corresponding beams for the left and right eye images respectively. The beams are then coupled out via the coupled one-dimensional grating 207 and combined to form a three-dimensional virtual image.

[0103] Optionally, the diffractive waveguide 200 includes at least one of a straight-tooth grating, a helical-tooth grating, or a blazed grating.

[0104] Optionally, an infrared reflective layer or an infrared absorbing layer may be provided on one side of the windshield 400.

[0105] The windshield 400 is typically curved, but can also be flat. The angle between the windshield 400 and the horizontal plane is set according to the placement of the head-up display device and its emitted beam. The infrared reflective layer or infrared absorbing layer is used to reflect or absorb infrared light incident on the windshield 400.

[0106] In one embodiment, the angle between the windshield 400 and the horizontal plane is set to 20°-45° according to the field of view of the coupled beam, thereby preventing the beam from being higher or lower than the normal receiving position of the human eye.

[0107] Specifically, an infrared reflective layer or an infrared absorption layer is provided on one side of the windshield 400 to prevent the heating caused by infrared irradiation from deforming, including but not limited to the focusing device 300 and the diffractive waveguide 200, thus affecting the imaging position and imaging quality.

[0108] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A head-up display device, characterized in that, include: Image source, used to emit an image beam; A diffractive waveguide, comprising a waveguide substrate and a coupling-in structure and a coupling-out structure located on at least one side of the waveguide substrate, wherein the coupling-in structure is used to couple the image beam into the waveguide substrate, the image beam propagates through the waveguide substrate by total internal reflection to the coupling-out structure, and the coupling-out structure is used to couple the image beam out of the waveguide substrate; A focusing device, located in the outgoing light path of the coupling structure, includes an imaging lens group and a collimating lens group. It is used to modulate the outgoing light beams from different regions of the coupling structure to produce different angles, so that the outgoing light beams from different fields of view are modulated by the focusing device and reflected by the windshield, and then imaged at at least two positions at different distances from the windshield.

2. The head-up display device according to claim 1, characterized in that, The focusing device includes an imaging lens group with positive optical power and a collimating lens group with optical power, wherein the imaging lens group is located on the side of the collimating lens group closer to the diffractive waveguide.

3. The head-up display device according to claim 2, characterized in that, The imaging lens group includes at least one lens, which includes a spherical lens, a secondary higher-order aspherical lens, or a freeform surface lens.

4. The head-up display device according to claim 2, characterized in that, The collimating lens group includes at least one microlens array, at least one Fresnel lens array, or a freeform lens.

5. The head-up display device according to claim 2, characterized in that, At least one parameter of the collimating lens group is gradually changed along at least one direction perpendicular to the optical axis of the focusing device.

6. The head-up display device according to claim 5, characterized in that, The optical power of the collimating lens group decreases along the direction closer to the windshield.

7. The head-up display device according to claim 1, characterized in that, The image source includes a first image source and a second image source, and the diffractive waveguide includes a first diffractive waveguide and a second diffractive waveguide; The first image source is used to emit a left-eye image beam, which is transmitted through the first diffractive waveguide, modulated by the focusing device, and reflected by the windshield to form a left-eye image. The second image source is used to emit a right-eye image beam, which is transmitted through the second diffractive waveguide, modulated by the focusing device, and reflected by the windshield to form a right-eye image.

8. The head-up display device according to claim 7, characterized in that, The focusing device includes a first focusing device and a second focusing device, wherein the first focusing device is used to modulate the left eye image beam and the second focusing device is used to modulate the right eye image beam.

9. The head-up display device according to claim 1, characterized in that, The diffractive waveguide further includes a pupil-expanding structure, which includes a first pupil-expanding structure and a second pupil-expanding structure, and the coupling-out structure includes a first coupling-out structure and a second coupling-out structure. The image beam includes a left-eye image beam and a right-eye image beam. The left-eye image beam is coupled into the coupling structure and then passes through the first pupil dilation structure and the first coupling structure before being output. The right-eye image beam is coupled into the coupling structure and then passes through the second pupil dilation structure and the second coupling structure before being output.

10. The head-up display device according to claim 9, characterized in that, The first pupil dilator structure and the second pupil dilator structure are located on the first side of the coupling structure, and the first coupling out structure and the second coupling out structure are located on the first side of the coupling structure; or The coupling structure is located between the first pupil dilator structure and the second pupil dilator structure, and the coupling structure is located between the first coupling outlet structure and the second coupling outlet structure. The first pupil dilator structure and the first coupling outlet structure are located on the same side of the coupling structure.

11. The head-up display device according to claim 9, characterized in that, Both the pupil expansion structure and the coupling structure include gratings, and the depth of the gratings increases along the direction of beam transmission.

12. The head-up display device according to claim 1, characterized in that, The diffractive waveguide also includes a reflective layer located in the coupling structure and / or the coupling structure.

13. The head-up display device according to claim 12, characterized in that, The coupling structure is located on the side of the waveguide substrate away from or close to the image source, and the reflective layer is located on the opposite side of the coupling structure; and / or The coupling structure is located on the side of the waveguide substrate away from the image source, and the reflective layer is located on the side of the waveguide substrate closer to the image source.

14. The head-up display device according to claim 1, characterized in that, The diffractive waveguide includes an input one-dimensional grating and an output two-dimensional grating, or the diffractive waveguide includes an input one-dimensional grating, a pupil-expanding one-dimensional grating, and an output one-dimensional grating.

15. The head-up display device according to claim 1, characterized in that, The diffractive waveguide includes at least one of a straight-tooth grating, a helical-tooth grating, or a blazed grating.

16. The head-up display device according to claim 1, characterized in that, An infrared reflective layer or an infrared absorbing layer is provided on one side of the windshield.

Images