Head-up display system and vehicle

Abstract

The present invention relates to a head-up display system and vehicle. The head-up display system of the present invention includes: a projection unit, the projection unit includes a display screen, a first linear polarizer is provided on the light-emitting surface of the display screen; a second linear polarizer is arranged opposite the first linear polarizer, and the transmission axis of the second linear polarizer is parallel to the transmission axis of the first linear polarizer; and a first functional film, configured as a birefringent film, and located between the first linear polarizer and the second linear polarizer; wherein the first functional film is used to convert light outside a preset viewing angle range of a first light emitted from the display screen and passing through the first linear polarizer into elliptically polarized light; and is used to allow light within the preset viewing angle range of the first light to be transmitted while maintaining its polarization direction unchanged. The head-up display system and vehicle of the present invention can avoid stray light outside the viewing angle range of the head-up display system, thereby improving user comfort.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a head-up display system and a vehicle. Background Art

[0002] Head-up display systems, also known as heads-up displays (HUDs), are currently widely used in aircraft flight control instruments. With technological advancements, they are now becoming increasingly common in automobiles. HUDs are designed to improve vehicle safety, allowing drivers to focus their attention on the road and reduce accidents. In HUD systems of related art, the light beam emitted by the projector undergoes a series of reflections before being transmitted to a reflective screen, such as the display area of ​​the windshield, where it is reflected and ultimately enters the human eye. However, these HUD systems often exhibit unwanted stray light outside the display viewing angle, impacting the user experience. Summary of the Invention

[0003] Based on this, it is necessary to provide a head-up display system and a vehicle that can avoid stray light outside the viewing angle of the head-up display system and improve the user experience.

[0004] A first aspect of an embodiment of the present application provides a head-up display system, including:

[0005] A projection unit, the projection unit comprising a display screen, a light emitting surface of the display screen being provided with a first linear polarizer;

[0006] a second linear polarizer disposed opposite to the first linear polarizer, with a transmission axis of the second linear polarizer parallel to the transmission axis of the first linear polarizer; and

[0007] The first functional film is configured as a birefringent film and is located between the first linear polarizer and the second linear polarizer. The first functional film is used to convert the light outside the preset viewing angle range of the first light emitted from the display screen and passing through the first linear polarizer into elliptically polarized light; and is used to allow the light within the preset viewing angle range of the first light to pass through with its polarization direction unchanged.

[0008] In the above scheme, a first linear polarizer and a second linear polarizer are arranged opposite each other with their transmission axes parallel to each other, and a first functional film (a birefringent film) is disposed between the first and second linear polarizers. Thus, light emitted from the display screen, after passing through the first linear polarizer, is converted into linearly polarized light polarized in a certain direction, namely, the first light. After passing through the first functional film, light outside the preset viewing angle range of this first light is converted into elliptically polarized light, while light within the preset viewing angle range is transmitted through the display with its polarization direction unchanged. In other words, within the first light, linearly polarized light with a wider viewing angle is converted into elliptically polarized light and is filtered out or significantly reduced in brightness upon passing through the second polarizer. Meanwhile, linearly polarized light with a narrower viewing angle passes through the first functional film and the second polarizer with its polarization direction unchanged, and finally enters the human eye after being reflected by at least one reflector. Corresponding to the light emitted by the display screen, the light with a larger viewing angle range (corresponding to the light outside the preset viewing angle range in the first light) is filtered out or the brightness is greatly weakened by the first polarizer, the first functional film and the second polarizer, and will not or rarely enter the human eye, effectively reducing the excess stray light of the head-up display system caused by the presence of this part of the light.

[0009] In one embodiment, the thickness of the first functional film is positively correlated with the preset viewing angle range. Thus, when the thickness of the first functional film is thicker, the stray light elimination effect is better.

[0010] In one embodiment, the optical axis of the extraordinary light of the first functional film is parallel to the light emission direction of the display screen, so as to ensure that the image seen by the human eye is symmetrical between the left and right eyes, resulting in better imaging effect.

[0011] In one embodiment, the first functional film is disposed on a surface of the first linear polarizer facing the second linear polarizer, thereby making it easier to install the first functional film.

[0012] In one embodiment, the head-up display system further includes a first optical lens, which is located on a side of the first functional film facing away from the first linear polarizer. The second linear polarizer is located on a surface of the first optical lens facing the first functional film, and is spaced apart from the first functional film at a predetermined distance. This predetermined distance allows the first optical lens and the second polarizer to function as thermal insulators, minimizing heat transfer from the first functional film to the second polarizer, which could affect the normal operation of downstream devices in the light propagation path, such as reflectors.

[0013] In one embodiment, the first optical lens is configured as a thermal mirror, which can reduce the amount of sunlight entering the head-up display system, thereby preventing sunlight in the operating environment from flowing back onto the projection unit and causing damage to the projection unit.

[0014] In one embodiment, the head-up display system further includes a reflective screen and at least one reflective mirror, wherein the at least one reflective mirror is configured to reflect the light emitted from the second linear polarizer to the reflective screen.

[0015] In one embodiment, the reflector includes a flat reflector and a curved reflector;

[0016] The plane reflector is used to reflect the light emitted by the second linear polarizer to the curved reflector, and the curved reflector is used to reflect the light reflected by the plane reflector to the reflective screen. The curved reflector can be used to magnify the image distance and visual size.

[0017] In one embodiment, the projection unit includes a backlight module, the display screen is configured as a liquid crystal display screen, and the backlight module is disposed on a side of the display screen away from the first linear polarizer.

[0018] A second aspect of an embodiment of the present application provides a vehicle, comprising the above-mentioned head-up display system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the overall structure of the head-up display system provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the optical path of the head-up display system provided in an embodiment of the present application;

[0021] Figure 3 This is a schematic diagram of the equivalent structure of the head-up display system provided in an embodiment of the present application;

[0022] Figure 4 A comparison graph showing the relative relationship between brightness and viewing angle of light in a head-up display system provided by an embodiment of the present application and related technologies;

[0023] Figure 5 This is a schematic diagram of an equivalent structure of another structure of the head-up display system provided in an embodiment of the present application.

[0024] Description of Figure Numbers:

[0025] 100. Head-up display system;

[0026] 10. First linear polarizer; 20. Second linear polarizer;

[0027] 30. Projection unit; 31. Display screen;

[0028] 40. First optical lens;

[0029] 50. First functional film;

[0030] 61. Plane reflector; 62. Curved reflector;

[0031] 70. Front windshield. DETAILED DESCRIPTION

[0032] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0038] Head-up display systems are early flight assistance systems used in aircraft. With the advancement of science and technology, they are increasingly being used in automobiles. These systems display crucial driving information, such as speed, engine rpm, fuel consumption, tire pressure, navigation, and information from connected smart devices, right in the driver's field of view on the windshield in real time. This allows drivers to see driving information without having to look down, thus avoiding distractions from the road ahead and eliminating potential driving hazards.

[0039] The head-up display system in related art generally includes a projector, a main control module, and at least one reflector, etc. The light emitted by the projector can appropriately display the image in front of the windshield through the reflector, etc. for the user to view.

[0040] Considering the uniformity of imaging within the display area of ​​the front windshield, the viewing angle of the outgoing light from the projector display screen is generally set to be larger. This will result in excess stray light outside the viewing angle of the display area of ​​the front windshield (i.e., the viewing angle of the head-up display system), which seriously reduces the user experience.

[0041] Based on the above problem, the present application arranges a first functional film and a second linear polarizer on the light-emitting side of the projection unit. The first functional film can convert the light with a larger viewing angle in the output light of the projector into elliptically polarized light. After passing through the second polarizer, the elliptically polarized light is filtered out by the second polarizer or the brightness is greatly weakened, and ultimately will not or rarely enter the human eye, thereby effectively solving the stray light outside the viewing angle range of the head-up display system.

[0042] The head-up display system and vehicle according to the embodiments of the present application are described below with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic diagram of the overall structure of the head-up display system provided in an embodiment of the present application. Figure 2 A schematic diagram of the optical path of the head-up display system provided in an embodiment of the present application, Figure 3 This is a schematic diagram of the equivalent structure of the head-up display system provided in an embodiment of the present application.

[0044] Reference Figure 1 、 Figure 2 、 Figure 3 The head-up display system 100 provided in an embodiment of the present application includes a projection unit 30, a second linear polarizer 20, and a first functional film 50. The projection unit 30 includes a display screen 31 and a first linear polarizer 10. The first linear polarizer 10 is disposed on the light exit surface of the display screen 31. The second linear polarizer 20 is disposed opposite the first linear polarizer 10, and the transmission axis of the second linear polarizer 20 is parallel to the transmission axis of the first linear polarizer 10. The first functional film 50 is configured as a birefringent film and is located between the first linear polarizer 10 and the second linear polarizer 20.

[0045] The first functional film 50 is used to convert the light outside the preset viewing angle range in the first light emitted from the display screen 31 and passing through the first linear polarizer 10 into elliptically polarized light; and is used to allow the light within the preset viewing angle range in the first light to pass through with its polarization direction unchanged.

[0046] In the above scheme, a first linear polarizer 10 and a second linear polarizer 20 are arranged opposite each other with their transmission axes parallel to each other, and a first functional film 50, comprising a birefringent film, is disposed between the first and second linear polarizers 10 and 20. As a result, light emitted from the display screen 31, after passing through the first linear polarizer 10, is converted into linearly polarized light polarized in a certain direction, namely, the first light. After passing through the first functional film 50, light outside the preset viewing angle range of this first light is converted into elliptically polarized light, while light within the preset viewing angle range is transmitted through the display screen with its polarization direction unchanged. In other words, within the first light, linearly polarized light with a wider viewing angle range is converted into elliptically polarized light and filtered out when passing through the second linear polarizer 20. Meanwhile, linearly polarized light with a narrower viewing angle range passes through the first and second functional films 50 and 20 with its polarization direction unchanged, and finally enters the human eye after being reflected by at least one reflector. Among the light rays emitted from the display screen 31, the light rays with a larger viewing angle range (corresponding to the light rays outside the preset viewing angle range in the first light rays) are filtered out by the first linear polarizer 10, the first functional film 50 and the second linear polarizer 20, or even if they are not completely filtered out, their brightness is greatly reduced, and they will not or rarely enter the human eye, thereby effectively reducing the stray light of the head-up display system caused by the presence of this part of the light rays.

[0047] Among them, the type of display screen 31 can be selected according to actual needs. In a possible embodiment, the display screen 31 can be, for example, a liquid crystal display screen. When the display screen 31 is a liquid crystal display screen, the projection unit 30 can also include a backlight module (not shown). The backlight module is arranged on the side of the display screen 31 away from the first linear polarizer 10, and is used to provide a light source for the liquid crystal display screen 31.

[0048] In addition, in the embodiment of the present application, the first linear polarizer 10 and the second linear polarizer 20 are arranged relative to each other, which means that the first linear polarizer 10 and the second linear polarizer 20 are arranged directly opposite each other. For example, the first linear polarizer 10 and the second linear polarizer 20 can be arranged in parallel, and the first functional film 50 is located between the first linear polarizer 10 and the second linear polarizer 20. In this way, it can be ensured that the light emitted from the display screen 31 passes through the first linear polarizer 10, the first functional film 50, and the second linear polarizer 20 before being emitted. For example, the first linear polarizer 10 and the second linear polarizer 20 can both be configured as polarizers.

[0049] The transmission axis of the second linear polarizer 20 is parallel to the transmission axis of the first linear polarizer 10, which means that the polarization directions of the second linear polarizer 20 and the first linear polarizer 10 are parallel. After passing through the first linear polarizer 10, the light emitted from the display screen 31 becomes linearly polarized light, namely the first light.

[0050] In the embodiment of the present application, the light outside the preset viewing angle range in the first light can be converted into elliptically polarized light after passing through the first functional film 50 .

[0051] In addition, the first functional film 50 is configured as a birefringent film layer, which means that the first functional film 50 is a birefringent medium that can double-refract the first light emitted from the display screen 31 and passing through the first polarizer 10 .

[0052] Figure 4 A comparison graph showing the relative relationship between the brightness and viewing angle of the light of the head-up display system 100 provided in an embodiment of the present application and related technologies.

[0053] Reference Figure 4 The solid line curve illustrates a curve showing a relative relationship between the brightness of light and the viewing angle of the head-up display system 100 provided in an embodiment of the present application, and the dotted line curve illustrates a curve showing a relative relationship between the brightness of light and the viewing angle of the head-up display system 100 in a related art.

[0054] Depend on Figure 4 It can be seen that the brightness of light (stray light) outside the target viewing angle range of -A to +A of the head-up display system 100 is significantly reduced. And the light intensity within the target preset range of -A to +A of the head-up display system 100 does not change, effectively ensuring the uniformity and brightness of the display within the target viewing angle range. Figure 4 The comparison curve corresponds to Figure 3 In the structure, the angle P corresponds to the viewing angle range of the first light emitted from the display screen 31 after passing through the first linear polarizer 10, and the angle Q corresponds to the viewing angle range of the head-up display system 100. Figure 3 In the embodiment of the present application, the brightness of the light of the head-up display system 100 is significantly reduced outside the target viewing angle range of -A to +A, and the brightness within the target viewing angle range of -A to +A is roughly the same as that in the related art.

[0055] It is understandable that Figure 4 The example only illustrates a case where the brightness of light (stray light) outside the target viewing angle range of -A to +A of the head-up display system 100 is significantly reduced, but the present application is not limited to this. In fact, when the parameters of the first functional film 50 are appropriately selected, the light (stray light) outside the target viewing angle range of -A to +A of the head-up display system 100 can even be almost completely filtered out.

[0056] In the embodiment of the present application, the thickness of the first functional film 50 is positively correlated with the preset viewing angle range of the first light. In other words, the thicker the first functional film 50, the stronger the filtering or weakening effect of the first light over a wide viewing angle range, and the better the effect of eliminating stray light in the head-up display system.

[0057] In the embodiment of the present application, the extraordinary light axis of the first functional film 50 is parallel to the light emission direction of the display screen 31. This ensures that the image seen by the left and right eyes is symmetrical, resulting in a better imaging effect. It is understood that the light emission direction of the display screen 31 can be, for example, the normal direction of the display screen 31.

[0058] Further, refer to Figure 3 The first functional film 50 is disposed on the surface of the first linear polarizer 10 facing the second linear polarizer 20. This facilitates relatively simple installation of the first functional film 50. For example, the first functional film 50 can be adhered to the surface of the first linear polarizer 10 facing away from the display screen 31 using a transparent optical adhesive. Of course, the present application is not limited to this. Alternatively, a dedicated light-transmitting optical lens can be disposed between the first linear polarizer 10 and the second linear polarizer 20, with the first functional film 50 attached to the light-transmitting optical lens.

[0059] In the embodiment of the present application, the head-up display system 100 further includes a first optical lens 40, which is located on a side of the first functional film 50 facing away from the first linear polarizer 10. The second linear polarizer 20 is disposed on a surface of the first optical lens 40 facing the first functional film 50 and maintains a preset distance from the first functional film 50. In the above embodiment, the second linear polarizer 20 maintains a preset distance from the first functional film 50 because the projection unit 30 generates significant heat during operation. By setting this preset distance, the first optical lens 40 and the second linear polarizer 20 can serve as thermal insulation, while also minimizing heat transfer from the first functional film 50 to the second linear polarizer 20, which could affect the normal operation of downstream components in the light propagation path, such as reflectors.

[0060] Of course, the setting position of the first functional film 50 is not limited thereto, and can also be set on the side surface of the first optical lens 40 away from the first functional film.

[0061] In the present application, refer to Figure 3 The first optical lens 40 is configured as a thermal mirror. This can reduce the amount of sunlight entering the head-up display system 100, thereby preventing sunlight from backflowing onto vulnerable components in the head-up display system, such as the display screen 31 of the projection unit 30, causing damage to the display screen 31.

[0062] Figure 5 This is a schematic diagram of an equivalent structure of another structure of the head-up display system 100 provided in an embodiment of the present application.

[0063] In some other examples, refer to Figure 5 As shown, the first optical lens 40 can be, for example, transparent glass, so that it can play a role of heat insulation on the one hand, and can also serve as a support carrier for the second linear polarizer 20 on the other hand.

[0064] Further, continue to refer to Figure 1 The head-up display system 100 may further include a reflective screen (eg, a front windshield 70 ) and at least one reflector, wherein the at least one reflector is configured to reflect the light emitted from the second linear polarizer 20 to the reflective screen.

[0065] In a specific implementation, the reflector includes a plane reflector 61 and a curved reflector 62. The plane reflector 61 is used to reflect the light emitted by the second linear polarizer 20 to the curved reflector 62, and the curved reflector 62 is used to reflect the light reflected by the plane reflector 61 to the inner surface of the front windshield 70. The curved reflector 62 can be used to magnify the image distance and visual size.

[0066] In some embodiments, the head-up display system 100 further includes a dust cover (not shown). The dust cover can be, for example, a translucent plastic cover that prevents dust from entering the head-up display system 100. In other embodiments, the dust cover can be a translucent glass cover, which not only prevents dust from entering the head-up display system 100 but also reduces deformation of the cover caused by heat.

[0067] The following combination Figure 2 , illustrating the working process of the head-up display system 100 in an embodiment of the present application.

[0068] Light emitted from the display screen 31 of the projection unit 30 passes through the first linear polarizer 10 and is converted into linearly polarized light. This linearly polarized light then passes through the first functional film 50, converting the linearly polarized light with a wider viewing angle into elliptically polarized light. This light is then filtered out by the second linear polarizer 20. The linearly polarized light with a narrower viewing angle, however, remains polarized and passes through the second linear polarizer 20. It is then reflected by the plane mirror 61 and the curved mirror 62, and finally reflects off the reflective screen before entering the human eye. The light entering the human eye forms a virtual image in front of the human eye.

[0069] An embodiment of the present application further provides a vehicle, which includes the head-up display system 100 of the aforementioned embodiment. It can be understood that the front windshield of the vehicle can be used as a reflective screen.

[0070] It should be noted that the head-up display system in this embodiment has been described in detail in the aforementioned embodiments and can bring the same or similar technical effects, so it will not be described in detail here.

[0071] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A head-up display system, characterized in that: include: A projection unit, the projection unit comprising a display screen, a first linear polarizer being provided on a light emitting surface of the display screen; a second linear polarizer, disposed opposite to the first linear polarizer, with a transmission axis of the second linear polarizer parallel to the transmission axis of the first linear polarizer; as well as a first functional film configured as a birefringence film and positioned between the first linear polarizer and the second linear polarizer; The first functional film is used to convert light outside a preset viewing angle range of the first light emitted from the display screen and passing through the first linear polarizer into elliptically polarized light; and to allow light within the preset viewing angle range of the first light to pass through with its polarization direction unchanged; The first functional film is disposed on a surface of the first linear polarizer facing the second linear polarizer, and the first functional film is adhered to a surface of the first linear polarizer facing away from the display screen by transparent optical adhesive; The head-up display system also includes a first optical lens, which is located on the side of the first functional film away from the first linear polarizer. The second linear polarizer is arranged on the side surface of the first optical lens facing the first functional film and maintains a preset distance from the first functional film.

2. The head-up display system according to claim 1, characterized in that: The film thickness of the first functional film is positively correlated with the preset viewing angle range.

3. The head-up display system according to claim 1, characterized in that: The optical axis of the extraordinary light of the first functional film is parallel to the light emitting direction of the display screen.

4. The head-up display system according to claim 1, characterized in that: The first optical lens is configured as a hot mirror.

5. The head-up display system according to any one of claims 1 to 3, characterized in that: The head-up display system further includes a reflective screen and at least one reflective mirror, wherein the at least one reflective mirror is configured to reflect the light emitted from the second linear polarizer to the reflective screen.

6. The head-up display system according to claim 5, characterized in that: The reflector includes a plane reflector and a curved reflector; The plane reflector is used to reflect the light emitted by the second linear polarizer to the curved reflector, and the curved reflector is used to reflect the light reflected by the plane reflector to the reflective screen.

7. The head-up display system according to claim 1, characterized in that: The projection unit further includes a backlight module. The display screen is configured as a liquid crystal display screen. The backlight module is arranged on a side of the display screen away from the first linear polarizer.

8. A vehicle, characterized in that: The head-up display system comprises the head-up display system according to any one of claims 1 to 7.

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