Panoramic head-up display device and panoramic head-up display system

Abstract

The invention provides a panoramic head-up display device and a panoramic head-up display system. In one aspect, there is provided a panoramic head-up display device for projecting image light to a shading area of a windshield, the panoramic head-up display device comprising: a light source configured to provide light; the light ray regulation and control unit is arranged in a light path of the light rays, and the light ray regulation and control unit is configured to carry out asymmetric regulation and control on angle distribution of the light rays, so that a first divergence angle of the image light rays output by the panoramic head-up display device in the vertical direction is smaller than a second divergence angle in the horizontal direction; the first divergence angle is limited in a preset range, so that the image light is projected in the shielding area in the vertical direction. Therefore, display quality and driving safety can be improved.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically, to panoramic head-up display devices and panoramic head-up display systems. Background Technology

[0002] With the development of smart cockpit technology, panoramic head-up display (PHUD) technology has gradually become the focus of the industry.

[0003] PHUD systems in this technology typically place the display screen, which serves as the image source, at the bottom of the dashboard near the windshield. The light carrying the image information emitted by the display screen is reflected by the imaging area located at the bottom of the windshield and transmitted to the driver's or passenger's eye box.

[0004] To avoid stray light and ghosting, and to consider overall power consumption, an opaque shaded area (i.e., a black area or black border) is placed in the imaging area of ​​the windshield. Regulations have specific requirements for the location and size of the windshield's light-transmitting area; the shaded area is generally located below the driver's lower field of vision. Therefore, the shaded area is narrow in the vertical direction, requiring a smaller longitudinal field of view for the PHUD, and consequently, a smaller exit angle for the display screen.

[0005] However, the displays of this technology have large emission angles in both the horizontal and vertical directions. This wide-angle light emission characteristic is mismatched with the specific optical requirements of PHUDs, causing light to overflow from the shielded area, thus affecting the visual experience and potentially interfering with driving safety. Summary of the Invention

[0006] This section provides a general overview of this disclosure, rather than a full disclosure of the entire scope or all features of this disclosure.

[0007] According to one aspect of this disclosure, a PHUD device is provided. The PHUD device projects image light onto a shaded area of ​​a windshield. The PHUD device includes a light source and a light control unit. The light source is configured to provide light. The light control unit is disposed in the optical path of the light and is configured to asymmetrically control the angular distribution of the light, such that a first divergence angle in the vertical direction of the image light output by the PHUD device is smaller than a second divergence angle in the horizontal direction, and the first divergence angle is limited within a predetermined range so that the image light is projected vertically onto the shaded area.

[0008] According to another aspect of this disclosure, a PHUD system is provided. The PHUD system includes a windshield and a PHUD device. The windshield includes a light-transmitting area and a shielding area located at the edge of the light-transmitting area. The PHUD device is configured to project image light into the shielding area, wherein a light control unit of the PHUD device is configured to limit a first divergence angle within a predetermined range such that the image light is projected vertically into the shielding area.

[0009] According to the above technical solution, by introducing a light control unit with asymmetric control function into the optical path of the light provided by the light source, the vertical divergence angle can be specifically compressed to strictly match the narrow longitudinal dimension of the windshield's obstructed area, while maintaining or adaptively adjusting the horizontal divergence angle to meet the lateral field of view requirements of panoramic display. This effectively reduces or even eliminates the adverse optical effects caused by light overflowing into the light-transmitting area, improving display quality and driving safety. Attached Figure Description

[0010] The features and advantages of embodiments of the present disclosure will become more readily understood from the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be enlarged or reduced to show details of specific components. In the drawings: Figure 1 This is a schematic diagram of the optical path of a PHUD system in a related technology, shown from a horizontal perspective.

[0011] Figure 2 Shown from a vertical perspective Figure 1 A schematic diagram of the optical path of the PHUD system.

[0012] Figure 3 This is a schematic diagram of the optical path of a PHUD system according to an embodiment of the present disclosure, shown from a horizontal perspective.

[0013] Figure 4 Shown from a vertical perspective Figure 3 A schematic diagram of the optical path of the PHUD system.

[0014] Figure 5 This is a schematic diagram illustrating the optical principle of the light control unit for angle control according to an embodiment of the present disclosure.

[0015] Figure 6 This is a schematic diagram of the optical path of a PHUD system according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0016] Figure 7 Shown from a vertical perspective Figure 6 A schematic diagram of the optical path of the PHUD system.

[0017] Figure 8This is a schematic diagram of the optical path of a PHUD system using a light control unit according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0018] Figure 9 Shown from a vertical perspective Figure 8 A schematic diagram of the optical path of the PHUD system.

[0019] Figure 10 This is a schematic diagram of the optical path of a PHUD system using a light control unit according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0020] Figure 11 Shown from a vertical perspective Figure 10 A schematic diagram of the optical path of the PHUD system.

[0021] Figure 12 This is a schematic diagram of the optical path of a PHUD system using a light control unit according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0022] Figure 13 Shown from a vertical perspective Figure 12 A schematic diagram of the optical path of the PHUD system.

[0023] Figure 14 This is a schematic diagram of the optical path of a PHUD system according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0024] Figure 15 Shown from a vertical perspective Figure 14 A schematic diagram of the optical path of the PHUD system.

[0025] Figure 16 This is a schematic diagram of the optical path of a PHUD system according to another embodiment of the present disclosure, shown from a horizontal perspective.

[0026] Figure 17 Shown from a vertical perspective Figure 16 A schematic diagram of the optical path of the PHUD system.

[0027] In the accompanying drawings, the same or corresponding technical features or components are represented by the same or corresponding reference numerals. Detailed Implementation

[0028] The present disclosure will now be described in detail with reference to the accompanying drawings and exemplary embodiments. It should be noted that the following detailed description of the present disclosure is for illustrative purposes only and is not intended to limit the scope of the disclosure.

[0029] It should be noted that, for clarity, not all features of a particular embodiment are described or shown in the specification and drawings. Furthermore, to avoid unnecessary details obscuring the technical solutions of interest in this disclosure, only the device structure closely related to the technical solutions of this disclosure is described and shown in the specification and drawings, while other details that are not closely related to the technical content of this disclosure and are known to those skilled in the art are omitted.

[0030] First, before describing the specific structure of the PHUD device provided in this disclosure, it is necessary to discuss in detail the problems existing in the related technologies mentioned above in order to more clearly understand the technical solution of this disclosure.

[0031] As discussed earlier, PHUD systems using this technology face optical matching challenges. Specifically, to meet automotive-grade display brightness requirements, PHUD systems typically employ displays such as Thin-Film Transistor Liquid Crystal Displays (TFT-LCDs) as the image source. These displays have a wide viewing angle, meaning their emitted light has a large divergence angle.

[0032] In typical automotive applications, displays can achieve viewing angles of ±88 degrees or even wider in both the horizontal and vertical directions. In contrast, PHUD systems are constrained by the vehicle's physical structure and regulatory requirements, resulting in very stringent and asymmetrical angular requirements for their imaging optical path. Particularly concerning is the obstructed area at the bottom of the windshield. Regulations strictly limit the position and size of the windshield's light-transmitting area, directly leading to a very narrow vertical dimension (i.e., the height of the windshield) for PHUD imaging. Therefore, to ensure the image precisely fills the obstructed area without overflowing, the PHUD system typically requires a very small vertical field of view, generally around 2 degrees.

[0033] Reference Figure 1 and Figure 2 When a display 100' with a large divergence angle (e.g., ±88 degrees) is directly applied to a PHUD system, this creates a significant contradiction between "wide emission" and "narrow reception".

[0034] like Figure 1 As shown, in the horizontal direction, since the shielding area 22 typically spans the entire width of the windshield (from the left A-pillar to the right A-pillar), the overflow of light S1 projected by the display screen 100' may be blocked by the A-pillars, but the problem is not yet obvious. However, Figure 2In the vertical direction shown, the problem becomes fully apparent. Of the wide-angle light S1 emitted by the display screen 100', only a portion of the light (shown by the solid line in the figure) is correctly projected into the shielding area 22 and reflected to the eye box 30, while a large amount of light from the edges (shown by the dashed line in the figure) extends beyond the upper or lower boundary of the shielding area 22. The light extending beyond the upper boundary is projected into the light-transmitting area 24 of the windshield 20.

[0035] Since the windshield 20 is designed primarily for transmittance and driver visibility, the curvature, thickness variation, and wedge angle parameters of its light-transmitting area 24 are typically optimized for far-field vision or traditional head-up displays (HUDs), but not for the near-field imaging path of a PHUD. Therefore, when image light from the PHUD overflows into the light-transmitting area 24 and is seen by the driver, the sudden changes in optical path and reflection angle result in noticeable ghosting, severe image distortion, and uneven brightness, significantly reducing display quality and potentially interfering with the driver's normal vision.

[0036] On the other hand, light exceeding the boundary of the shielding area 22 may also be refracted outside the vehicle through the windshield 20. When viewed from the front side outside the vehicle, bright spots or images that should not be visible may be seen at the bottom of the windshield 20. This not only disrupts the integrity of the vehicle's appearance, but more seriously, if the PHUD displays sensitive information such as caller ID or navigation address, this information may be viewed by pedestrians or drivers of other vehicles outside the vehicle, leading to a serious user privacy breach.

[0037] In response, this disclosure proposes a PHUD device and PHUD system, which introduces a light control unit that can "asymmetrically" shape and limit light through the light control unit, so that the image light projected onto the shielded area of ​​the windshield is within the shielded area.

[0038] Below, first refer to Figure 3 and Figure 4 The PHUD device 100 according to embodiments of the present disclosure will be described in detail.

[0039] The PHUD device 100 includes a light source 120 and a light control unit 140.

[0040] Light source 120 is configured to provide light S1. Light source 120 can be a backlight device (such as...) Figure 3 and Figure 4As shown), for example, a light-emitting diode (LED) light source. In this case, the PHUD device 100 typically also includes a display panel 160 located downstream of the backlight device 120 in the optical path to receive backlight provided by the backlight device 120. It is conceivable that the light source 120 may also be the self-emissive display panel itself, for example, a micro LED.

[0041] The light control unit 140 is located downstream of the light source 120 and is disposed in the optical path of the light S1 provided by the light source 120. For example, when the light source 120 is a backlight device such as an LED light source, the light control unit 140 is disposed in the optical path of the light provided by the LED light source to control the light. It is understood that this light has not yet become image light through output from the PHUD device 100. However, when the light source 120 is a miniature LED, the light provided by the light source 120 is the image light, and in this case, the light control unit 140 is directly disposed in the optical path of the image light.

[0042] The light control unit 140 is configured to asymmetrically control the angle distribution of the light S1, that is, to apply different degrees of angle restriction in the vertical and horizontal directions, so that after being controlled by the light control unit 140, the first divergence angle of the image light output by the PHUD device 100 in the vertical direction is smaller than the second divergence angle in the horizontal direction, and the first divergence angle is limited to a predetermined range so that the image light is projected into the shielding area 22 in the vertical direction.

[0043] It is understandable that the "predetermined range" is not arbitrarily selected, but is calculated by reverse optical path tracing based on the vertical height of the shielding area 22 of the windshield 20, the distance from the display panel 160 to the windshield 20, and the design position of the eye box 30.

[0044] In this way, the image light emitted from the PHUD device 100 can be projected entirely and accurately into the shielded area 22, at least in the vertical direction, without overflowing upwards into the light-transmitting area 24 or downwards into the interior trim area. This effectively reduces or even eliminates ghosting and image distortion, and improves brightness uniformity, thereby significantly enhancing display quality and driving safety.

[0045] It is conceivable that the second divergence angle can also be limited within a predetermined range so that the image light is also projected into the shading area 22 in the horizontal direction.

[0046] This method prevents the image content from being seen from the front side of the vehicle, thereby improving the overall appearance of the vehicle and preventing the leakage of user privacy.

[0047] To more clearly illustrate this angle control, it is conceivable that the initial light emitted by the light source 120 can be defined with a horizontal divergence angle of A1 and a vertical divergence angle of A2. For conventionally used light sources, A1 and A2 are typically large and close in value (e.g., both ±60 degrees). After being adjusted by the light control unit 140, the horizontal divergence angle of the output light becomes B1 (i.e., the second divergence angle), and the vertical divergence angle becomes B2 (i.e., the first divergence angle). In embodiments of this disclosure, these angles satisfy a specific ratio relationship: In the horizontal direction, the following conditions are met: 0.15 ≤ B1 / A1 ≤ 1; and In the vertical direction, the following condition holds: 0.05 ≤ B² / A² ≤ 0.3.

[0048] For the above numerical range, it can be understood that in the horizontal direction, the divergence angle ratio of light is between 0.15 and 1. This means that the light in the horizontal direction can remain unchanged (ratio of 1) or be moderately compressed (e.g., ratio of 0.15). This is because PHUDs typically need to span the entire dashboard in the horizontal direction, requiring a large field of view, and are often obstructed by A-pillars on the left and right sides. Therefore, the restrictions in the horizontal direction are relatively loose, mainly to accommodate the range of the eye box and prevent light energy waste.

[0049] In the vertical direction, the divergence angle ratio of the light is strictly limited to between 0.05 and 0.3. This means that the original large-angle light is strongly compressed into a very narrow range (e.g., from ±60 degrees to ±3 degrees to ±18 degrees). If the ratio is greater than 0.3, the compression is insufficient, and the light may still overflow the shielded area; if the ratio is less than 0.05, although the anti-overflow effect is good, it will cause the emitted light to be too collimated, making the user's eye box have too little range of movement in the vertical direction, and the image will not be visible even with a slight change in posture.

[0050] The specific implementation of the light control unit 140 can be varied. This will be explained in detail below.

[0051] In some implementations, the light control unit 140 may employ microstructures to constrain the light angle in order to match the required angle of the PHUD device by filtering out or selecting large-angle light.

[0052] It is conceivable that the light control unit 140 may include optical devices such as privacy films, gratings, or any combination thereof. (Refer to...) Figure 5 These optical devices contain microstructures 1400 internally, which are configured to define a specific transmission angle threshold α. For example... Figure 5As shown, when the incident angle of ray S1 with respect to microstructure 1400 in the vertical direction is less than the transmission angle threshold α (e.g.) Figure 5 (As shown by the solid arrow passing through the gap), light ray S1 is allowed to pass through microstructure 1400 and exit; however, when the incident angle in the vertical direction is greater than the transmission angle threshold α, light ray S1 will be blocked, absorbed, or deflected into an invalid optical path by microstructure 1400.

[0053] This physical interception method filters out the portion of the originally large-angle light S1 that exceeds angle α. For example, by selecting a privacy screen protector with a transmission angle threshold of ±10 degrees, the emitted light can be limited to within ±10 degrees. This effectively solves the problem of light overflowing outside the shielded area, and the device is thin, light, and easy to integrate.

[0054] In some embodiments, the light control unit 140 may employ an active light control scheme to shape the light. In this embodiment, the light control unit 140 is configured to provide a first optical power in the vertical direction and a second optical power in the horizontal direction. To achieve the aforementioned asymmetric divergence angle control, i.e., to give the image light the aforementioned first and second divergence angles, the absolute value of the second optical power should be less than the first optical power.

[0055] Optical power is a physical quantity that characterizes the ability of an optical system to converge or diverge light. The greater the optical power, the stronger the converging or diverging effect on light. Therefore, by providing a first optical power with a larger absolute value in the vertical direction, the light control unit 140 has a stronger focusing (collimating) capability in the vertical direction.

[0056] In this embodiment, the light control unit 140 does not filter out large-angle light when controlling the light angle. Instead, it converges or collimates the light through the design of the optical power. As a result, the light energy of light exceeding the predetermined angle is not lost, thereby effectively improving the light efficiency.

[0057] It is conceivable that the light control unit 140 can be a lens, at least one of which, the light-incident surface and the light-outcident surface, is curved. This curved surface has a first radius of curvature in the vertical direction and a second radius of curvature in the horizontal direction. Since optical power is inversely proportional to the radius of curvature (i.e., the smaller the radius of curvature, the more curved the surface, and the greater the optical power), the absolute value of the first radius of curvature should be smaller than the absolute value of the second radius of curvature.

[0058] Understandably, in optical design, surfaces can be convex or concave, and their radii of curvature can be positive or negative, so absolute values ​​are used for comparison. This significant difference in the design of radii of curvature directly results in vertical light rays being more strongly refracted and deflected when passing through a lens, thus being significantly converged; while horizontal light rays are refracted less, maintaining a larger divergence angle.

[0059] Regarding the configuration of the light source, the PHUD device 100 disclosed herein can be adapted to various types of light sources.

[0060] As mentioned before, refer to Figure 3 and Figure 4 The light source 120 can be a backlight device, such as an LED light source. In addition, it is conceivable that the light source 120 can also be a miniature LED.

[0061] Reference Figure 6 and Figure 7 The light source 120 employs an array of micro-LEDs. Micro-LEDs are characterized by self-illumination, high brightness, and miniaturization. When the display screen is a micro-LED display panel, the light control unit 140 can be a microlens disposed (e.g., directly attached) on each micro-LED; alternatively, the light control unit 140 can be multiple lenses arranged in an array, each lens corresponding to one of the multiple micro-LEDs, for example, the multiple lenses are spaced apart from the multiple micro-LEDs. It is understood that the above method also applies to the case where the light source 120 is an array of multiple LEDs, and will not be elaborated further here.

[0062] like Figure 6 and Figure 7 As shown, because micro-LEDs are point light sources and do not require components such as diffusers found in traditional LCD displays and backlight modules, their structure is very compact. Each microlens is designed according to the aforementioned asymmetric surface shape, thereby directly shaping the light source into asymmetric features that meet the requirements of a PHUD at its source. Figure 7 As shown, the vertical beam of light is highly collimated by the microlens and strictly confined within the shielded area; while Figure 6 The horizontal beam maintains a large divergence angle. This approach not only offers high optical efficiency but also allows for a thinner PHUD device.

[0063] For solutions using lenses as the light control unit 140, the lens surface design can be further subdivided into various specific implementation scenarios, depending on the specific vehicle model requirements, screen layout, and eye box coverage. The following will combine... Figures 8 to 13 Provide a detailed description.

[0064] First, refer to Figure 8 and Figure 9 This scenario primarily targets PHUD systems where the screen spans the entire dashboard (from the driver's side to the passenger's side). For example, there might be a display module on the driver's side, a center screen, and a passenger's side, or a single display module extending from the driver's side to the passenger's side. In this layout, the obstruction area 22 on the windshield 20 also extends from the left A-pillar to the right A-pillar. Since the horizontal display area is entirely black bordered, and the extreme positions on both sides are blocked by the A-pillars of the vehicle, horizontal light leakage (i.e., light leakage on the left and right sides) is generally not sensitive, or in other words, horizontal light convergence is unnecessary.

[0065] For this purpose, the curved surface 142 of lens 140 is designed as a ring surface. For example... Figure 8 As shown, in the horizontal direction, the contour line of surface 142 is straight, which means that its radius of curvature in the horizontal direction is infinite (or that it is a plane). Therefore, lens 140 has no optical power in the horizontal direction, and the light ray S1 does not deflect in the horizontal direction when passing through lens 140. That is, the second divergence angle maintains the original large angle of the light source. And... Figure 9 In the vertical direction shown, the curved surface 142 exhibits a distinct curvature and has a finite first radius of curvature. By precisely calculating and adjusting this first radius of curvature, the conic coefficient, and the aspherical coefficient, the lens 140 generates sufficient optical power in the vertical direction to highly collimate the light rays.

[0066] As a result, the vertical light emission angle (i.e., the first divergence angle) is compressed to approximately ±10 degrees, precisely matching the height of the shielded area. This type of annular lens is relatively simple to design and manufacture, has low cost, and effectively solves the problem of light spillage in the vertical direction.

[0067] Furthermore, in another scenario, restrictions are imposed simultaneously in both the horizontal and vertical directions, specifically targeting wide-viewing-box requirements. For example, in some high-end vehicles, to further enhance privacy or prevent light from escaping from the side windows, it is necessary to restrict the horizontal viewing angle. At the same time, since the PHUD needs to serve both the driver and front passenger, the horizontal field of view cannot be too small, requiring coverage of a relatively wide viewing box area.

[0068] In this regard, refer to Figure 10 and Figure 11 It can be envisioned that the curved surface 142 of lens 140 is designed as a biconical surface. A biconical surface is a complex freeform surface characterized by having different radii of curvature and conic coefficients in two orthogonal directions (horizontal and vertical). For example... Figure 10 and Figure 11As shown, lens 140 exhibits a curved shape in both the horizontal and vertical directions, indicating that it has optical power in both directions. Moreover, the curvature of lens 140 in the vertical direction is much greater than that in the horizontal direction; that is, the absolute value of the first radius of curvature in the vertical direction is smaller than the absolute value of the second radius of curvature in the horizontal direction.

[0069] In a specific simulation example, the conicity factor in the horizontal direction can be set to 7, while the conicity factor in the vertical direction can be set to -0.55. After adjustment by the light control unit 140, as shown... Figure 10 As shown, the horizontal beam divergence angle is constrained to approximately ±40 degrees; Figure 11 As shown, the vertical beam divergence angle is constrained to approximately ±10 degrees.

[0070] This ensures that light does not spill out from the sides, that both the driver and front passenger can clearly see the image, and that there is no light spillage in the vertical direction.

[0071] In another scenario, restrictions are applied simultaneously in both the horizontal and vertical directions, specifically targeting narrow-viewing-box requirements. This scenario primarily applies to PHUD modes intended for driver-only viewing, such as when used in conjunction with a HUD. The HUD displays distant views, such as flight paths and AR interactive information like warnings; the PHUD displays close-up views, such as speed and fuel consumption—critical driving information that doesn't require the passenger's attention. Therefore, the viewing area can be further reduced to achieve higher brightness and better privacy.

[0072] In this case, refer to Figure 12 and Figure 13 The light control unit 140 still uses a biconical lens, but its surface parameters have been adjusted. Specifically, compared to the previous scenario, the lens 140 in this embodiment has a further reduced radius of curvature in the horizontal direction (becomes more curved), thereby enhancing its horizontal light-gathering ability. Figure 12 As shown, after adjustment, the horizontal beam divergence angle is further narrowed to approximately ±20 degrees; and as... Figure 13 As shown, the vertical beam divergence angle remains within ±10 degrees to match the height of the shielding area.

[0073] This narrow field-of-view design concentrates light energy highly in the driver's eye area, greatly improving the brightness of the image and ensuring that the image is completely invisible to other parts of the vehicle, achieving an excellent privacy display effect.

[0074] In some implementations, for an architecture that uses a backlight device, such as an LED light source, as the light source 120 and is used in conjunction with a display panel 160, such as a TFT-LCD, a diffuser 180 is usually provided between the light source 120 and the display panel 160 in order to ensure the brightness uniformity of the display screen.

[0075] Reference Figure 14 and Figure 15 In the PHUD device 100, the light source 120 is a backlight device, the light control unit 140 is located between the light source 120 and the display panel 160, and the diffuser 180 can be placed between the light source 120 and the light control unit 140. In this case, the angle output by the light control unit 140 is the target angle.

[0076] However, it is conceivable that, with reference to Figure 16 and Figure 17 The diffuser 180 can also be located between the light control unit 140 and the display panel 160 (i.e., located on the light-emitting side of the light control unit 140).

[0077] The function of a diffuser at 180° is to disperse and homogenize the light, but this inevitably increases the divergence angle of the beam. For example... Figure 16 and Figure 17 As shown, if the angle of the light output by the light control unit 140 is already the limit angle of the occlusion area (e.g., ±10 degrees in the vertical direction), then when these rays pass through the diffuser 180, their angle will further increase (e.g., become ±11.2 degrees) due to the scattering effect. The extra 1.2 degrees of light will cause the image edges to blur or overflow the occlusion area, thereby destroying the aforementioned optical design intent.

[0078] In response, this disclosure proposes a "pre-compensation" mechanism. In this mechanism, the light control unit 140 is configured to output an intermediate light beam, the angle of which is designed to be smaller than the final target angle, in order to leave a margin for the diffuser to diffuse.

[0079] Specifically, assume that the required final light angle for the shielding area 22 of the windshield 20 is ±10 degrees vertically and ±40 degrees horizontally. It is also known that the selected diffuser 180 has specific scattering characteristics, introducing an angle increment of, for example, ±1.3 degrees. Therefore, when designing the light control unit 140, its target exit angle will not be set to ±10 degrees and ±40 degrees, but rather to smaller values. For example, the lens's exit angle in the vertical direction is designed to be ±8.7 degrees, and its exit angle in the horizontal direction is designed to be ±38.7 degrees. Thus, the ±8.7 degree intermediate light emitted from the lens, after passing through the diffuser 180, experiences increased divergence due to scattering, ultimately forming an image light that reaches exactly ±10 degrees; similarly, the horizontal intermediate light, after diffusion, reaches exactly ±40 degrees.

[0080] In this way, the light ultimately projected onto the windshield 20 still strictly conforms to the limits of the first and second divergence angles, thereby balancing brightness uniformity and angle control precision, ensuring that the anti-overflow effect is not sacrificed while the diffuser is introduced to improve image quality. Moreover, since the light is collimated and collected by the light control unit 140 before being diffused by the diffuser 180, the light efficiency can also be improved.

[0081] On the other hand, according to embodiments of this disclosure, such as Figure 3 and Figure 4 , Figure 6 and Figure 7 as well as Figures 14 to 17 As shown, a PHUD system 200 is also provided.

[0082] The PHUD system 200 includes a windshield 20 and a PHUD device 100.

[0083] The windshield 20 serves as the final reflective imaging element of the PHUD system 200, and includes a light-transmitting area 24 and a shielding area 22 located at the edge (typically the bottom) of the light-transmitting area 24.

[0084] The PHUD device 100 is typically installed inside the dashboard, with its light outlet aligned with the shaded area 22 of the windshield 20. The light control unit 140 of the PHUD device 100 is configured to strictly limit the first divergence angle of the image light in the vertical direction within a predetermined range. This predetermined range matches the angle of the shaded area 22 in the vertical direction.

[0085] When the PHUD system 200 is working, the light emitted by the light source 120 is asymmetrically shaped by the light control unit 140 to form a flat beam. This beam, for example, passes through the display panel 160 carrying image information and is precisely projected into the shielding area 22 of the windshield 20.

[0086] Because the angle of light in the vertical direction is strictly controlled, the light will not overflow upwards into the light-transmitting area 24, thus eliminating ghosting and distortion seen by the driver; the light will also not overflow downwards, avoiding interior glare; at the same time, because a large field of view is maintained in the horizontal direction, the image can be laid out horizontally to form a panoramic display effect.

[0087] Although this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the specific embodiments described and shown herein. Various changes can be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the claims of this disclosure.

[0088] The features mentioned and / or shown in the foregoing description of exemplary embodiments of this disclosure may be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. Such combinations or substitutions should also be considered as including within the scope of protection of this disclosure.

Claims

1. A panoramic head-up display device for projecting image light onto the obstructed area of ​​a windshield, characterized in that, The panoramic head-up display device includes: A light source, configured to provide light; and A light control unit is disposed in the optical path of the light. The light control unit is configured to asymmetrically control the angular distribution of the light, such that the first divergence angle of the image light output by the panoramic head-up display device in the vertical direction is smaller than the second divergence angle in the horizontal direction, and the first divergence angle is limited within a predetermined range so that the image light is projected into the occlusion area in the vertical direction.

2. The panoramic head-up display device according to claim 1, characterized in that, The second divergence angle is limited to a predetermined range so that the image light is projected into the occluded area in the horizontal direction.

3. The panoramic head-up display device according to claim 1 or 2, characterized in that, The light emitted by the light source has a divergence angle of A1 in the horizontal direction and a divergence angle of A2 in the vertical direction; The light, after being controlled by the light control unit, has a divergence angle of B1 in the horizontal direction and a divergence angle of B2 in the vertical direction, wherein 0.15≤B1 / A1≤1 and 0.05≤B2 / A2≤0.

3.

4. The panoramic head-up display device according to claim 1 or 2, characterized in that, The light control unit is configured to provide a first optical power in the vertical direction and a second optical power in the horizontal direction with an absolute value less than the first optical power, so that the image light has a first divergence angle and a second divergence angle.

5. The panoramic head-up display device according to claim 4, characterized in that, The light control unit is a lens, and at least one of the light-incident surface and the light-exit surface of the lens is a curved surface. The curved surface has a first radius of curvature in the vertical direction and a second radius of curvature in the horizontal direction. The absolute value of the first radius of curvature is less than the absolute value of the second radius of curvature.

6. The panoramic head-up display device according to claim 5, characterized in that, The surface is an annular surface, and the first radius of curvature is infinite; or, the surface is a biconical surface, and both the first radius of curvature and the second radius of curvature are finite values.

7. The panoramic head-up display device according to claim 1 or 2, characterized in that, The light control unit is provided with a microstructure, which is configured to limit a transmission angle threshold. When the incident angle of the light with respect to the microstructure in the vertical direction is less than the transmission angle threshold, the light is allowed to pass through. When the incident angle in the vertical direction is greater than the transmission angle threshold, the light is blocked, absorbed, or deflected into an invalid light path by the microstructure.

8. The panoramic head-up display device according to claim 7, characterized in that, The light control unit includes at least one of a privacy screen and a grating.

9. The panoramic head-up display device according to claim 1 or 2, characterized in that, The light source is a backlight device, and the panoramic head-up display device also includes a display panel located downstream of the optical path of the backlight device to receive the backlight provided by the backlight device, and the light control unit is located between the backlight device and the display panel.

10. The panoramic head-up display device according to claim 9, characterized in that, It also includes a diffuser sheet located between the backlight device and the display panel.

11. The panoramic head-up display device according to claim 10, characterized in that, The diffuser is located between the light control unit and the display panel. The light control unit is configured to output intermediate light, such that the intermediate light is diffused by the diffuser to form the image light having the first divergence angle and the second divergence angle.

12. The panoramic head-up display device according to claim 1 or 2, characterized in that, The light source is a plurality of light-emitting diodes or micro-light-emitting diodes arranged in an array, and the light control unit is a microlens disposed on each light-emitting diode or micro-light-emitting diode; or the light control unit is a plurality of lenses arranged in an array, and the plurality of lenses are disposed in a one-to-one correspondence with the plurality of light-emitting diodes or micro-light-emitting diodes.

13. A panoramic head-up display system, characterized in that, include: A windshield, including a light-transmitting area and a shielding area located at the edge of the light-transmitting area; as well as According to any one of claims 1 to 12, the panoramic head-up display device is configured to project image light onto the occluded area, wherein the light control unit of the panoramic head-up display device is configured to limit the first divergence angle within a predetermined range so that the image light is projected into the occluded area in the vertical direction.

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