Off-axis bifocal optical system based on w-hud technology

Abstract

The utility model discloses a kind of off-axis bifocal optical system based on W-HUD technology belonging to head-up display technical field, image source, for emitting light and image;First reflector with high-low curvature double area, the light emitted by the image source is reflected by first reflector to form the light path of 2 light rays propagation, and the first reflector is located above image source;Second reflector, for reflecting 2 light rays propagation, windshield glass, the windshield glass is located obliquely above second reflector, and the inside direction of the windshield glass is provided with human eye.The utility model forms 2 light paths of different high-low curvature by image source emission to first reflector, is reflected to windshield glass by second reflector, and is reflected to human eye again, form the image face of near virtual image face and far virtual image face 2 different focal lengths that human eye sees, can alleviate driving visual fatigue, improve the practicality, use comfort and safety of W-HUD technology.

Description

Technical Field

[0001] This utility model belongs to the field of head-up display technology and relates to an off-axis dual-focal-surface optical system based on W-HUD technology. Background Technology

[0002] HUD (Head-Up Display) projects important driving information such as speed and navigation onto the windshield in front of the driver, allowing the driver to see this information without looking down or turning their head.

[0003] HUDs include the mainstream AR-HUD (Augmented Reality Head-Up Display). AR-HUDs have a longer VID (Virtual Image Distance) virtual image distance. With a longer VID, the human eye perceives the image as farther away, while with a shorter VID, the human eye perceives the image as closer. Existing HUDs are gradually developing towards functions such as dual focal planes, multi-focal planes, and continuous zoom, but they are all based on the optical solutions proposed by AR-HUDs. The main advantages of AR-HUDs are the longer VID and the ability to interact with real-world scenes.

[0004] Unlike AR-HUD, W-HUD (Windshield Head-Up Display) has only one focal plane and a fixed VID focal length, which can easily lead to visual fatigue for drivers, greatly reducing the practicality and comfort of W-HUD and compromising safety.

[0005] Therefore, there is an urgent need to design a dual-focal-plane W-HUD solution to solve the visual fatigue and limited usage scenarios caused by the existing W-HUD with only a single focal plane, so as to improve driving safety and flexibility. Utility Model Content

[0006] This invention provides an off-axis dual-focal-plane optical system based on W-HUD technology, aiming to solve the problems of fixed VID focal length in existing W-HUDs, which easily leads to visual fatigue for drivers, reduces the practicality and comfort of W-HUDs, and has low safety.

[0007] To achieve the above objectives, this utility model provides an off-axis dual-focal-surface optical system based on W-HUD technology, comprising:

[0008] Image source, used to emit light and images;

[0009] A first reflecting mirror has dual regions of high and low curvature. The first reflecting mirror is provided with a high curvature freeform surface region and a low curvature freeform surface region. The high curvature freeform surface region is located below the low curvature freeform surface region. The light emitted from the image source is reflected by the first reflecting mirror to form two light paths. The first reflecting mirror is located above the image source.

[0010] The second reflector is used to reflect the propagation of two beams of light, and the second reflector is located on one side of the first reflector.

[0011] A windshield is located diagonally above a second reflector. An eye is located on the inner side of the windshield. Two beams of light reflected by the second reflector are reflected by the windshield to the eye. One beam forms a near-virtual image plane, and the other beam forms a far-virtual image plane.

[0012] Preferably, the center of the near virtual image plane is the near center, the center of the far virtual image plane is the far center, the line connecting the human eye and the far center of the far virtual image plane is the projection axis, and the near center of the near virtual image plane does not fall on the projection axis.

[0013] Preferably, the second reflector is a freeform mirror.

[0014] The advantages of this utility model over the prior art are:

[0015] This invention provides an off-axis dual-focal-plane optical system based on W-HUD technology. The system emits two beams of light with different curvatures through an image source to a first mirror. The beams are then reflected by a second mirror onto the windshield and then onto the human eye, forming two image planes with different focal lengths: a near virtual image plane and a far virtual image plane. This system can alleviate driving visual fatigue and improve the practicality, comfort, and safety of W-HUD technology.

[0016] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the optical path projection structure of this utility model;

[0018] Figure label:

[0019] 1. Image source; 2. First reflecting mirror; 21. High curvature freeform surface region; 22. Low curvature freeform surface region; 3. Second reflecting mirror; 4. Windshield; 5. Human eye; 6. Near virtual image plane; 7. Far virtual image plane; 8. Projection axis; 9. Near center; 10. Far center. Detailed Implementation

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] To achieve the above objectives, this utility model provides an off-axis dual-focal-surface optical system based on W-HUD technology, applied in the automotive field. Installed in front of the driver's seat, it projects a virtual image onto the windshield 4 using the optical path formed by image source 1. This allows the driver to see both static and dynamic images in front of the windshield 4 while looking ahead. Examples include virtual images projected from image source 1 for navigation, and virtual images projected to display speed and fuel levels on the instrument panel. (See reference...) Figure 1 As shown, it includes:

[0023] Image source 1, used to emit light and images;

[0024] The first reflecting mirror 2 has a dual region with high and low curvature. The first reflecting mirror 2 is provided with a high curvature freeform surface region 21 and a low curvature freeform surface region 22. The high curvature freeform surface region 21 is located below the low curvature freeform surface region 22. The light emitted from the image source 1 is reflected by the first reflecting mirror 2 to form two light paths. The first reflecting mirror 2 is located above the image source 1.

[0025] The second reflector 3 is used to reflect the propagation of two beams of light. The second reflector 3 is located on one side of the first reflector 2. The second reflector 3 is a freeform mirror.

[0026] The windshield 4 is located diagonally above the second reflector 3. A human eye 5 is provided on the inner side of the windshield 4. Two beams of light reflected by the second reflector 3 are reflected by the windshield 4 to the human eye 5. One beam of light forms a near virtual image plane 6, and the other beam of light forms a far virtual image plane 7.

[0027] HUD (Head-Up Display): A head-up display is a device that projects important information into the driver's line of sight, allowing the driver to obtain information without looking down, thus improving driving safety and convenience.

[0028] The Projection Generation Unit (PGU) is a key component in a HUD system used to generate images, responsible for converting image signals into optical signals for projection. PGUs include, but are not limited to, TFT (Thin Film Transistor), LCOS (Liquid Crystal on Silicon), and DLP (Digital Light Processing). Each PGU solution has its advantages: TFT technology is mature, low-cost, and provides clear image display; LCOS features high resolution and high contrast; and DLP excels in color performance and response speed. The appropriate PGU solution can be selected based on the specific application scenario and performance requirements to meet different display needs.

[0029] In this embodiment, the first reflector 2 is a freeform mirror with two regions of different curvatures. Through processing, a high-curvature freeform surface region 21 and a low-curvature freeform surface region 22 are formed. The higher the curvature, the greater the bending degree of the lens and the stronger the light diffusion ability. It can reflect and diffuse light to a larger area on the main second reflector 3, providing a prerequisite for the subsequent generation of a far focal plane and a larger image. The near virtual image plane 6 and the far virtual image plane 7 are both located on the outside of the windshield 4.

[0030] The optical path of the near-virtual image plane 6 is: image source 1 - low curvature freeform surface region 22 second reflecting mirror 3 windshield 4 human eye 5 near-virtual image plane 6 position. The near-virtual image plane 6 can be used in situations where a clear understanding of the road conditions ahead is required, such as traffic jams, following other vehicles, and narrow roads.

[0031] The optical path of the far virtual image plane 7 is as follows: image source 1 - high curvature freeform surface region 21 - second reflecting mirror 3 windshield 4 human eye 5 position of far virtual image plane 7. The far virtual image plane 7 can be used in high-speed and express lanes, as well as national highways and urban roads.

[0032] Among them, the center of the near virtual image plane 6 is the near center 9, the center of the far virtual image plane 7 is the far center 10, the line connecting the human eye 5 and the far center 10 of the far virtual image plane 7 is the projection axis 8, the near center 9 of the near virtual image plane 6 does not fall on the projection axis 8, the near and far focal planes can be opened at the same time, and the driving information is distributed on different focal planes, avoiding the human eye 5 from being fixed at a single distance, which can alleviate visual fatigue of driving.

[0033] Compared to existing AR-HUDs, W-HUDs use a short VID, which makes the first reflector 2 and the second reflector 3 smaller, reducing the overall size of the HUD, manufacturing costs, and greatly increasing the spatial freedom of HUD installation in cars. W-HUDs also have a size advantage, and dual-focal HUDs can be used in compact or small cars. By choosing between two focal planes, driving becomes more interactive and flexible. Overall, it has the advantages of small size, low cost, and good dual-focal interactive experience.

[0034] In one embodiment, the VID of the W-HUD is generally around 4 meters. When the road is clear, the image displayed by the W-HUD can be easily observed, including the near virtual image plane 6 and the far virtual image plane 7. When there is a need to clearly understand the situation ahead, such as in traffic jams, following other vehicles, or narrow roads, the near virtual image plane 6 is used. The dual focal planes, one near and one far, distribute driving information on two focal planes with different focal lengths. This allows the driver to avoid fixing their visual focus on a specific and unique focal plane while driving, which can greatly reduce visual fatigue during driving and enable the flexible application of the HUD in multiple scenarios.

[0035] This invention provides an off-axis dual-focal-plane optical system based on W-HUD technology. The system emits two beams of light with different curvatures through an image source 1 to a first reflecting mirror 2. The beams are then reflected by a second reflecting mirror to the windshield 4 and then to the human eye 5, forming two image planes with different focal lengths: a near virtual image plane 6 and a far virtual image plane 72, as seen by the human eye 5. This system can alleviate driving visual fatigue and improve the practicality, comfort, and safety of W-HUD technology.

[0036] The technical principles of this utility model have been described above with reference to specific embodiments, which are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments; all technical solutions falling within the scope of this utility model's concept are protected. Other specific embodiments of this utility model that can be conceived by those skilled in the art without creative effort will also fall within the protection scope of this utility model.

Claims

1. An off-axis dual-focal-surface optical system based on W-HUD technology, characterized in that, include: Image source, used to emit light and images; A first reflecting mirror has dual regions of high and low curvature. The first reflecting mirror is provided with a high curvature freeform surface region and a low curvature freeform surface region. The high curvature freeform surface region is located below the low curvature freeform surface region. The light emitted from the image source is reflected by the first reflecting mirror to form two light paths. The first reflecting mirror is located above the image source. The second reflector is used to reflect the propagation of two beams of light, and the second reflector is located on one side of the first reflector. A windshield is located diagonally above a second reflector. An eye is located on the inner side of the windshield. Two beams of light reflected by the second reflector are reflected by the windshield to the eye. One beam forms a near-virtual image plane, and the other beam forms a far-virtual image plane.

2. The off-axis dual-focal-plane optical system based on W-HUD technology according to claim 1, characterized in that, The center of the near virtual image plane is the near center, the center of the far virtual image plane is the far center, the line connecting the human eye and the far center of the far virtual image plane is the projection axis, and the near center of the near virtual image plane does not fall on the projection axis.

3. The off-axis dual-focal-plane optical system based on W-HUD technology according to claim 1, characterized in that, The second reflecting mirror is a freeform mirror.

Images