Double-optical-path structure with continuous depth of field on far image surface and head-up display device

Abstract

The invention provides a double-light-path structure with continuous depth of field on a far image surface and a head-up display device, the double-light-path structure comprises a projection device Z1, and light emitted by the projection device Z1 forms close-distance projection and long-distance projection at a virtual image end after being reflected by a windshield WS. By controlling the included angle between the light L1 and the light L2, the included angle is larger than 30 degrees when a single light source is used and is larger than 25 degrees when double light sources are used, more natural and smooth visual transition can be effectively achieved, visual faults or abrupt feeling in a traditional projection mode is reduced, and the visual comfort degree is improved. And the configuration of a single light source or double light sources is adopted, so that the technology has higher flexibility. According to the head-up display device, the far and near projection virtual image perfectly fused with the real environment in vision can be presented, and on the basis of adding far projection and ground fusion, the dizziness caused by obvious projection distance difference when the view field is switched back and forth in far and near projection is reduced, so that the driving experience of a driver is improved.

Description

Technical Field

[0001] The present application belongs to the field of head-up displays, and specifically relates to a dual-light path structure with a continuous depth of field on a distant image plane and a head-up display device. Background Art

[0002] In the prior art, such as the patent application CN218630367U, the light emitted by the light source part of the image light source control part is refracted by a plane reflector and divided into two paths of light. One path enters the first section of the near projection light output tube, then passes through the plane reflector to enter the second section of the near projection light output tube, and finally emits light at its near projection diffuser plate; the other path enters the first section of the far projection light output tube, then passes through the plane reflector to enter the second section of the near projection light output tube, and finally emits light at its far projection diffuser plate.

[0003] Next, the generated near projection light source and far projection light source are respectively reflected by the primary curved mirror, the secondary curved mirror and the windshield to generate two separate projections, far projection and near projection, which are then received by the human eye.

[0004] The disadvantage of this technology is that the angle between the far projection image and the road surface is close to vertical, resulting in a weak fusion effect between the actual far projection image and the ground, and the navigation elements cannot play a good driving assistance role. At the same time, the projection distance between the far projection and the near projection is quite different. When the two images are switched between each other, the human eye is prone to fatigue due to the distance jump, and it has narrow applicability and is only suitable for PGU image light sources of projection types such as DLP / LCOS.

[0005] In addition to the technical shortcomings in the above patent application documents, the traditional technical methods mostly adopt optical design to change the optical path in the image source control part, so that the emitted light is multiple beams of light at different distances and positions, thereby realizing multiple projections at different distances. This method of changing the optical path by optical design of the image source control part is relatively complex to implement and difficult to adjust. Summary of the invention

[0006] In response to the defects of the above-mentioned prior art, the present application provides a dual-optical path structure and a head-up display device with a continuous depth of field on a distant image plane. By implementing a dual-optical path architecture in which the angle between the distant image plane and the road surface is less than 60°, a "one vertical and one oblique" image plane combination mode is formed. On the basis of increasing the fusion of the distant projection and the ground, the dizziness caused by the obvious difference in projection distance when the field of vision switches back and forth between far and near projections is reduced, thereby improving the driver's driving experience.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present application proposes a dual-optical path structure with a continuous depth of field on a distant image plane, the dual-optical path structure comprising a projection device Z1, the light emitted by the projection device Z1, after being reflected by the windshield WS, forms a close-range projection and a long-range projection at the virtual image end; wherein the projection device Z1 is a single light source or a dual light source; when the projection device Z1 is a single light source, the emitted light includes light L1 and light L2; the angle between the light L1 and the light L2 is greater than 30°; when the projection device Z1 is a dual light source, the angle between the first light source and the second light source is greater than 25°. The head-up display device proposed in the present invention forms near-distance and long-distance projections at the virtual image end by projecting light at different distances, ensuring that objects in the field of view remain clear at different distances, thereby achieving a continuous depth of field effect. This is of great significance for application scenarios that require clear visual presentation in complex or multi-layered environments (such as virtual reality, augmented reality, advanced driver assistance systems, etc.).

[0008] By controlling the angle between light L1 and light L2, such as greater than 30° for a single light source and greater than 25° for a dual light source, a more natural and smooth visual transition can be effectively achieved, reducing the visual discontinuity or abruptness in traditional projection methods, and improving visual comfort. The use of a single light source or a dual light source configuration gives this technology greater flexibility. The single light source configuration simplifies the design and is suitable for cost-sensitive scenes; while the dual light source configuration can provide higher light intensity and precise light path control, and is suitable for scenes with higher requirements for display effects. Under different projection effects at different distances, the projection distance of different focal lengths can be more accurately controlled, improving the adaptability and practicality of the system. Optimizing the light source configuration of the projection device Z1 (especially in dual light source mode) can effectively reduce the light interference between different light sources, improve the accuracy of light projection, and optimize image quality, which is especially suitable for applications that require fine display in complex environments.

[0009] Preferably, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a plane reflector M71; the plane reflector M71 is placed at any position of the light emitting surface of the light source, wherein a part of the light emitted by the single light source is reflected by the plane reflector M71 to form light L2; the other part of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0010] The present application utilizes the setting of the plane reflector M71, and provides a technical solution that can achieve clear images at different focal lengths through the combination of a single light source and the plane reflector M71. It has a relatively simple design, and through the optimization of the reflector, it can effectively improve the utilization efficiency of the light source and achieve a visual effect of continuous depth of field.

[0011] Preferably, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F1, and the wedge-shaped prism F1 is placed at any position of the light emitting surface of the light source, wherein a portion of the light emitted by the single light source is reflected from the first mirror surface of the wedge-shaped prism F1 to the second mirror surface, and is directly refracted through the third mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0012] By adding the wedge prism F1, the projection device Z1 can achieve accurate distribution and guidance of light based on a single light source, effectively improving the clarity of the image, the utilization rate of the light source, and the overall efficiency of the system. In addition, the design of the wedge prism F1 can also achieve a compact structure, flexible adjustment, and simplified optical design, thereby having better adaptability in multiple application scenarios.

[0013] Preferably, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a prism F2, wherein the prism F2 is placed at any position of the light emitting surface of the light source, wherein a portion of the light emitted by the single light source is refracted through the first mirror surface of the prism F2, and then refracted out through the second mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0014] This application uses prism F2. This design can achieve efficient light distribution and focus control based on a single light source, while optimizing the continuous depth of field effect and image quality. This structure has the advantages of simplified design, improved optical efficiency, reduced distortion, and lower costs, and is suitable for a variety of applications that require efficient optical design and high-quality projection.

[0015] Preferably, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F3, wherein the wedge-shaped prism F3 is placed at any position on the light emitting surface of the light source, wherein a portion of the light emitted by the single light source is refracted to the second mirror surface through the first mirror surface of the wedge-shaped prism F3, refracted from the second mirror surface to the third mirror surface, and then refracted out through the second mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0016] This application is based on the dual-light path structure design of the wedge prism F3. Through a single light source and precise refraction path distribution, it not only provides a continuous depth of field effect, but also achieves efficient use of the light source, reduces the complexity of the system, avoids optical distortion, and has the advantages of high light efficiency, low cost and high reliability. It is suitable for projection applications with high requirements on image quality and system compactness.

[0017] Preferably, the dual-light path structure described in the present application further includes a primary curved mirror M1 and a secondary curved mirror M2; wherein, The light L1 and the light L2 of the image light source combination module are reflected by the primary curved mirror M1 and the secondary curved mirror M2, and after being reflected by the windshield WS, form a short-distance projection and a long-distance projection at the virtual image end.

[0018] The dual-light path structure achieves a continuous depth of field effect through reflections from the primary and secondary curved mirrors and the additional reflection function of the windshield. By implementing a dual-light path architecture in which the angle between the far image plane and the road surface is less than 60°, a "one vertical and one oblique" image plane combination mode is formed. This increases the fusion of the far projection with the ground and reduces the dizziness caused by the obvious difference in projection distance when the field of view switches back and forth between far and near projections, thereby improving the driver's driving experience.

[0019] Preferably, there is no overlapping area between the short-distance projection and the long-distance projection in terms of spatial angle.

[0020] Preferably, the close-range projection is at a spatial distance of 4.5 m from human eyes.

[0021] Preferably, the long-distance projection is at a spatial distance of 4.6 to 7.8 m from human eyes.

[0022] The dual-optical path structure with continuous depth of field on the far image plane of this application brings clear and accurate projection effects by accurately setting the spatial distance between close-range and long-range projections and ensuring that the projection areas of the two do not overlap. It not only optimizes the image quality, but also improves the user's viewing experience. It is especially suitable for applications that require precise control of projection distance and focal length, such as virtual reality (VR), augmented reality (AR), and car displays.

[0023] In the second aspect, the present application also proposes a head-up display device, including the dual optical path structure described in the first aspect, and the head-up display device also includes a primary curved mirror M1, a secondary curved mirror M2 and a windshield WS. At least two image planes emitted from the dual optical path structure enter the primary curved mirror M1 and the secondary curved mirror M2 in sequence, and then enter the human eye after being reflected by the windshield WS, and finally form at least two virtual images at different positions and levels in front of the windshield WS.

[0024] The head-up display device described in this application combines a dual optical path structure with a reflector system, which can not only form multiple virtual image levels in front of the windshield, improve the depth and clarity of information display, but also greatly enhance driving safety, optimize space utilization, adapt to various ambient lighting conditions, and improve the stability and durability of the system. These technical advantages make the device particularly suitable for information display applications in modern cars, improving driving experience and safety.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. Continuous depth of field and clear virtual image display: multiple virtual images of different distances are formed simultaneously in the same visual area.

[0026] 2. Dual light source configuration and light path separation: The appropriate angle design between the light sources can effectively separate the light path, further reduce the power consumption of the light source, and increase the stability of the system and the uniformity of light.

[0027] 3.Optimized configuration of optical components: Different optical components are added to accurately adjust the path of light through refraction, reflection, etc.

[0028] 4. The use of curved mirrors improves reflection efficiency: The use of primary curved mirror M1 and secondary curved mirror M2 can improve the reflection efficiency of light.

[0029] 5. Projection without overlapping areas: close-range projection and long-range projection will not overlap in spatial angle.

[0030] 6. Enhanced driving safety: Drivers do not need to lower their heads to check the on-board instrument panel or other display devices, which can effectively reduce the risk of distraction during driving.

[0031] 7. Multi-level virtual image display and user experience: Multi-level display can enhance the presentation of information, allowing users to clearly obtain necessary driving data in different situations.

[0032] 8. Adapt to various lighting environments: As a display medium, the windshield can work stably under various lighting conditions and is not easily affected by strong external light, sunlight or interior lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the internal structure of the head-up display device of the present application.

[0034] Figure 2 It is a schematic diagram of a dual-light path structure with a continuous depth of field on a distant image plane according to an embodiment of the present application.

[0035] Figure 3 It is a schematic diagram of a dual-light path structure with a continuous depth of field on a distant image plane according to an embodiment of the present application.

[0036] Figure 4 It is a schematic diagram of a dual-light path structure with a continuous depth of field on a distant image plane according to an embodiment of the present application.

[0037] Figure 5 It is a schematic diagram of a dual-light path structure with a continuous depth of field on a distant image plane according to an embodiment of the present application.

[0038] Figure 6 It is a schematic diagram of a dual-light path structure with a continuous depth of field on a distant image plane according to an embodiment of the present application.

[0039] Figure 7 This is a schematic diagram of a dual-optical path structure with a continuous depth of field on a distant image plane and a head-up display device structure of the present application.

[0040] Figure 8 This is a schematic diagram of a dual-optical path structure with a continuous depth of field on a distant image plane and a head-up display device structure of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] Embodiment 1, refer to Figure 1 and Figure 2 As shown, the present application proposes a dual-light path structure with a continuous depth of field on a distant image plane, the dual-light path structure comprising a projection device Z1, the light emitted by the projection device Z1, after being reflected by the windshield WS, forms a close-range projection and a long-range projection at the virtual image end; wherein the projection device Z1 is a single light source or a dual light source; when the projection device Z1 is a single light source, the emitted light includes a light L1 and a light L2; the angle between the light L1 and the light L2 is greater than 30°; when the projection device Z1 is a dual light source, the angle between the first light source and the second light source is greater than 25°.

[0043] The head-up display device proposed in the present invention forms short-range and long-range projections at the virtual image end by projecting light at different distances, ensuring that objects in the field of view remain clear at different distances, thereby achieving a continuous depth of field effect. This is of great significance for application scenarios that require clear visual presentation in complex or multi-layered environments (such as virtual reality, augmented reality, advanced driver assistance systems, etc.). For example, it can be applied to a vehicle-mounted HUD to project instrument information, navigation instructions, etc. on the front windshield of the vehicle, and the driver does not need to lower his head to check the dashboard. Or aviation HUD: The pilot obtains flight data through the projection of the front window to improve flight safety.

[0044] This application can effectively achieve a more natural and smooth visual transition by controlling the angle between the light L1 and the light L2 to be greater than 30° when using a single light source and greater than 25° when using a dual light source, thereby reducing the visual discontinuity or abruptness in traditional projection methods and improving visual comfort. The use of a single light source or a dual light source configuration gives the technology greater flexibility. The single light source configuration simplifies the design and is suitable for cost-sensitive scenes; while the dual light source configuration can provide higher light intensity and precise light path control, and is suitable for scenes with higher requirements for display effects. Under different projection effects at different distances, the projection distance of different focal lengths can be controlled more accurately, improving the adaptability and practicality of the system. Optimizing the light source configuration of the projection device Z1 (especially in dual light source mode) can effectively reduce light interference between different light sources, improve the accuracy of light projection, and optimize image quality, which is especially suitable for applications that require fine display in complex environments.

[0045] Reference Figure 3 As shown, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a plane reflector M71; the plane reflector M71 is placed at any position of the light emitting surface of the light source, wherein a part of the light emitted by the single light source is reflected by the plane reflector M71 to form light L2; the other part of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0046] The present application utilizes the setting of the plane reflector M71, and provides a technical solution that can achieve clear images at different focal lengths through the combination of a single light source and the plane reflector M71. It has a relatively simple design, and through the optimization of the reflector, it can effectively improve the utilization efficiency of the light source and achieve a visual effect of continuous depth of field.

[0047] Reference Figure 4 As shown, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F1, and the wedge-shaped prism F1 is placed at any position of the light emitting surface of the light source, wherein a part of the light emitted by the single light source is reflected from the first mirror surface of the wedge-shaped prism F1 to the second mirror surface, and is directly refracted through the third mirror surface to form light L2; the other part of the light is light L1; the light L1 and the light L2 are combined to form an image light source combination module.

[0048] By adding the wedge prism F1, the projection device Z1 can achieve accurate distribution and guidance of light based on a single light source, effectively improving the clarity of the image, the utilization rate of the light source, and the overall efficiency of the system. In addition, the design of the wedge prism F1 can also achieve a compact structure, flexible adjustment, and simplified optical design, thereby having better adaptability in multiple application scenarios.

[0049] Reference Figure 5 As shown, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a prism F2, wherein the prism F2 is placed at any position of the light emitting surface of the light source, wherein a portion of the light emitted by the single light source is refracted through the first mirror surface of the prism F2, and then refracted out through the second mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0050] This application uses prism F2. This design can achieve efficient light distribution and focus control based on a single light source, while optimizing the continuous depth of field effect and image quality. This structure has the advantages of simplified design, improved optical efficiency, reduced distortion, and lower costs, and is suitable for a variety of applications that require efficient optical design and high-quality projection.

[0051] Reference Figure 6 As shown, in the dual optical path structure described in the present application, when the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F3, and the wedge-shaped prism F3 is placed at any position of the light emitting surface of the light source, wherein a part of the light emitted by the single light source is refracted to the second mirror surface through the first mirror surface of the wedge-shaped prism F3, refracted from the second mirror surface to the third mirror surface, and then refracted out through the second mirror surface to form light L2; the other part of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

[0052] This application is based on the dual-light path structure design of the wedge prism F3. Through a single light source and precise refraction path distribution, it not only provides a continuous depth of field effect, but also achieves efficient use of the light source, reduces the complexity of the system, avoids optical distortion, and has the advantages of high light efficiency, low cost and high reliability. It is suitable for projection applications with high requirements on image quality and system compactness.

[0053] Reference Figures 2 to 6 As shown, the dual-light path structure also includes the above-mentioned projection device Z1, and also includes a primary curved mirror M1 and a secondary curved mirror M2; wherein, The light L1 and the light L2 of the image light source combination module are reflected by the primary curved mirror M1 and the secondary curved mirror M2, and after being reflected by the windshield WS, form a short-distance projection and a long-distance projection at the virtual image end.

[0054] This dual-light path structure provides multiple advantages through reflection from the primary and secondary curved mirrors, as well as the additional reflection function of the windshield, including continuous depth of field, optimized image quality, improved optical efficiency, flexible focus control, and the ability to adapt to complex environments. Its compact design, improved stability and system reliability are particularly suitable for projection applications with high requirements on image quality, volume and environmental adaptability, such as automotive, aviation and mobile device scenarios.

[0055] Reference Figure 7 As shown, there is no overlapping area between the short-distance projection and the long-distance projection in terms of spatial angle.

[0056] In the present invention, the close-range projection is at a distance of 4.5 m from the human eye, and is usually used to display more detailed, high-resolution images, such as screen displays of personal devices, interactive content, etc.

[0057] The long-distance projection is 4.6 to 7.8 meters away from the human eye. It is usually used to display large-scale, low-resolution images, such as environmental projection, background images, etc.

[0058] The dual-optical path structure with continuous depth of field on the telephoto surface brings clear and precise projection effects by accurately setting the spatial distance between close-range and long-range projections and ensuring that the projection areas of the two do not overlap. This technology not only optimizes image quality, but also improves the user's viewing experience and has a wide range of application potential.

[0059] This structure is particularly suitable for applications that require precise control of projection distance and focal length, such as virtual reality (VR), augmented reality (AR), and in-vehicle displays. These applications usually require precise control of the display range and clarity of the image.

[0060] Example 2, refer to Figure 7 and Figure 8 As shown, a head-up display device includes a dual-light path structure, and also includes a primary curved mirror M1, a secondary curved mirror M2 and a windshield WS. At least two image planes emitted from the dual-light path structure enter the primary curved mirror M1 and the secondary curved mirror M2 in sequence, and then enter the human eye after being reflected by the windshield WS, and finally form at least two virtual images at different positions and levels in front of the windshield WS.

[0061] The head-up display device combines a dual optical path structure with a reflector system, which can not only form multiple virtual image levels in front of the windshield, improve the depth and clarity of information display, but also greatly enhance driving safety, optimize space utilization, adapt to various ambient lighting conditions, and improve system stability and durability. These technical advantages make the device particularly suitable for information display applications in modern cars, improving driving experience and safety.

[0062] Through the coordination of the primary and secondary curved mirrors, the clarity and stability of the image are ensured, the optical distortion in traditional display devices is reduced, the overlap of different projection areas is avoided, the image recognition and accuracy are improved, the display comfort is improved, and visual fatigue is reduced. It can display multiple key information at the same time, which improves the efficiency during driving or observation, ensures image stability and clarity, and maintains the best display effect even in complex lighting environments. Users can enjoy clear image display without adjusting the focal length. It has significant technical competitiveness in vehicle-mounted head-up displays, augmented reality (AR) displays, and other scenarios that require multi-level image display.

[0063] This application provides an advanced head-up display device with a continuous depth of field on a telescopic image plane. Through the coordinated work of the image light source combination module and the optical elements, the projection angle, graphic modeling and software algorithm are optimized to achieve a virtual image that can be clearly displayed at different focal lengths, greatly improving the display effect and driving experience of the HUD, and improving safety and comfort. This technology has broad application prospects, especially in autonomous driving and advanced driver assistance systems (ADAS).

[0064] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0065] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0066] Although the description of the present application is carried out in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes according to the above content. Therefore, all such substitutions, modifications and changes are included in the spirit and scope of the appended claims.

Claims

1. A dual-optical path structure with a continuous depth of field at a distant image plane, characterized in that: The dual-light path structure includes a projection device Z1, and the light emitted by the projection device Z1 forms a close-range projection and a long-range projection at the virtual image end after being reflected by the windshield WS; wherein the projection device Z1 is a single light source or a dual light source; when the projection device Z1 is a single light source, the emitted light includes a light L1 and a light L2; the angle between the light L1 and the light L2 is greater than 30°; when the projection device Z1 is a dual light source, the angle between the first light source and the second light source is greater than 25°.

2. A dual-optical path structure with a continuous depth of field at a remote image plane according to claim 1, characterized in that: When the projection device Z1 is a single light source, it also includes: a plane reflector M71; the plane reflector M71 is placed at any position of the light emitting surface of the light source, wherein a part of the light emitted by the single light source is reflected by the plane reflector M71 to form light L2; the other part of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

3. The dual-optical path structure with a continuous depth of field at a remote image plane according to claim 1, characterized in that: When the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F1, which is placed at any position on the light-emitting surface of the light source, wherein a portion of the light emitted by the single light source is reflected from the first mirror surface of the wedge-shaped prism F1 to the second mirror surface, and is directly refracted through the third mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

4. The dual-light path structure with a continuous depth of field at a remote image plane according to claim 1, characterized in that: When the projection device Z1 is a single light source, it also includes: a prism F2, which is placed at any position on the light emitting surface of the light source, wherein a portion of the light emitted by the single light source is refracted through the first mirror surface of the prism F2, and then refracted out through the second mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

5. The dual-light path structure with a continuous depth of field at a remote image plane according to claim 1, characterized in that: When the projection device Z1 is a single light source, it also includes: a wedge-shaped prism F3, which is placed at any position on the light-emitting surface of the light source, wherein a portion of the light emitted by the single light source is refracted to the second mirror surface through the first mirror surface of the wedge-shaped prism F3, refracted from the second mirror surface to the third mirror surface, and then refracted out through the second mirror surface to form light L2; the other portion of the light is light L1; the light L1 and light L2 are combined to form an image light source combination module.

6. A dual-optical path structure with a continuous depth of field at a remote image plane according to any one of claims 1 to 5, characterized in that: The projection device Z1 also includes a primary curved mirror M1 and a secondary curved mirror M2; wherein, The light L1 and the light L2 of the image light source combination module are reflected by the primary curved mirror M1 and the secondary curved mirror M2, and after being reflected by the windshield WS, form a short-distance projection and a long-distance projection at the virtual image end.

7. The dual-light path structure with a continuous depth of field at a remote image plane according to claim 1, characterized in that: There is no overlapping area between the short-distance projection and the long-distance projection in terms of spatial angle.

8. The dual-light path structure with a continuous depth of field at a remote image plane according to claim 6, characterized in that: The close-range projection is at a spatial distance of 4.5 m from human eyes.

9. The dual-light path structure with continuous depth of field at a remote image plane according to claim 6, characterized in that: The long-distance projection is at a spatial distance of 4.6 to 7.8 m from human eyes.

10. A head-up display device, characterized in that: The dual light path structure comprises the dual light path structure as claimed in any one of claims 1 to 5, and further comprises a primary curved mirror M1, a secondary curved mirror M2 and a windshield WS. At least two image planes emitted from the dual light path structure enter the primary curved mirror M1 and the secondary curved mirror M2 in sequence, and then enter the human eye after being reflected by the windshield WS, and finally form at least two virtual images at different positions and levels in front of the windshield WS.

Images