Head-up display device and vehicle

Abstract

The invention relates to a head-up display device and a vehicle. The head-up display device comprises a light-emitting element and an optical isolator, the light-emitting element is used for emitting emergent light, the optical isolator is arranged on the light emitting side of the light-emitting element, and the optical isolator comprises a first polarization element, a second polarization element and a third polarization element which are sequentially arranged along the optical axis in the propagation direction of the emergent light. The first polarization element is arranged to be capable of receiving and reflecting emergent light emitted by the light-emitting element to the second polarization element, the second polarization element is arranged to be capable of transmitting the emergent light to the third polarization element, and the third polarization element is arranged to be capable of receiving and reflecting the emergent light transmitted by the second polarization element; and the first polarization element is arranged to be capable of transmitting external light which sequentially passes through the third polarization element and the second polarization element and then is transmitted to the first polarization element. According to the head-up display device, the risk that external visible light enters the head-up display device to cause damage to the head-up display device can be reduced.

Description

Technical Field

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

[0002] A head-up display (HUD) is a system that projects driving information onto a transparent display device such as the windshield in front of the driver, so that the driver can see information such as speed and navigation without lowering his head. HUD improves driving safety by reducing the driver's line of sight and reduces the risk of accidents caused by distraction.

[0003] The head-up display in the related art is affected by external visible light, that is, light that enters the HUD from the outside against the light path, which can easily cause local overheating of the head-up display, burn its internal components, and cause damage to its internal components. Summary of the invention

[0004] Based on this, it is necessary to provide a head-up display device and a vehicle to reduce the risk of external visible light entering the head-up display device and causing damage to the head-up display device.

[0005] According to one aspect of the present application, a head-up display device is provided, the head-up display device comprising:

[0006] A light emitting element for emitting output light;

[0007] A first reflecting element and a second reflecting element, wherein the first reflecting element and the second reflecting element are sequentially arranged along a propagation direction of the emergent light; and

[0008] An optical isolator, comprising a first polarizing element, a second polarizing element and a third polarizing element sequentially arranged along a propagation direction of the outgoing light, wherein the first polarizing element is arranged on a reflection surface of the first reflecting element, the third polarizing element is arranged on a reflection surface of the second reflecting element, and along the propagation direction of the outgoing light, the second polarizing element is arranged between the first reflecting element and the second reflecting element;

[0009] The first polarization element is configured to receive and reflect the outgoing light emitted by the light-emitting element to the second polarization element, the second polarization element is configured to transmit the outgoing light to the third polarization element, and the third polarization element is configured to receive and reflect the outgoing light transmitted by the second polarization element; and the first polarization element is also configured to transmit external light that passes through the third polarization element and the second polarization element in sequence and then propagates to the first polarization element.

[0010] In one embodiment, the outgoing light emitted by the light-emitting element is in a first polarization state, the first polarization element is configured to reflect light in the first polarization state and transmit light in other polarization states, the second polarization element is configured to convert the outgoing light in the first polarization state into light in a third polarization state, and to convert light in the third polarization state into light in the second polarization state, and the third polarization element is configured to reflect light in the third polarization state.

[0011] In one embodiment, the first reflective element comprises a plane reflective mirror, and the second reflective element comprises a free-form reflective mirror.

[0012] In one embodiment, the second polarization element comprises a Faraday rotator, and the second polarization element rotates the polarization of the light by 45°.

[0013] In one embodiment, the second polarization element includes a body and a coil wound around the body, the coil is used to provide a magnetic field parallel to the optical axis to the body, and the material of the body includes magneto-optical material.

[0014] In one embodiment, the angle between the reflection axis of the first polarizing element and the reflection axis of the third polarizing element is 45°.

[0015] In one embodiment, the first polarizing element includes a reflective polarizer or a cold mirror film.

[0016] In one embodiment, the third polarizing element includes a reflective polarizer or a cold mirror film.

[0017] In one embodiment, the light emitting element and the second polarizing element are located on the same side of the first polarizing element.

[0018] According to another aspect of the present application, a vehicle is provided, comprising the head-up display device in any one of the above embodiments.

[0019] In the above-mentioned head-up display device, the outgoing light is reflected by the first polarizing element, then transmitted by the second polarizing element, and finally reflected by the third polarizing element, so as to be emitted from the head-up display device. It does not affect the normal display function of the head-up display device. At the same time, when natural light, especially visible light, flows back into the head-up display device, it will first pass through the third polarizing element and the second polarizing element in sequence, and then pass through the first polarizing element when it propagates to the first polarizing element. It can be understood that the external light passes through the first polarizing element, and will not be reflected by the first polarizing element against the light path of the outgoing light to the light-emitting element, so that the light-emitting element cannot be damaged. That is, the head-up display device of the present application can reduce the risk of external visible light entering the head-up display device and causing damage to the head-up display device. And the present application only needs to set the first polarizing element on the first reflecting element, set the third polarizing element on the second reflecting element, and add the second polarizing element between the first reflecting element and the second reflecting element. The structure is simple and cost-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a schematic structural diagram of a head-up display device in an embodiment of the present application.

[0021] FIG. 2 is a simplified schematic diagram of the polarization states of the outgoing light and the backflowing incident visible light after passing through various optical elements.

[0022] FIG3 is a schematic structural diagram of the Faraday rotator of the present application.

[0023] Description of Figure Numbers:

[0024] 10. Head-up display device;

[0025] 1. Light-emitting element;

[0026] 2. optical isolator; 21. first polarizing element; 22. second polarizing element; 221. body; 222. coil; 23. third polarizing element;

[0027] 31. a first reflecting element; 32. a second reflecting element;

[0028] 4. Dust-proof film; 5. Windshield. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that if 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", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, 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 intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that if 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 a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0035] Head-up display (HUD) technology is increasingly used in automobiles. It improves driving safety and convenience by projecting important driving information into the driver's field of vision. However, the head-up display (HUD) system can be damaged by external light. For example, in strong sunlight, there may be a problem of sunlight backflow, which refers to the sunlight focusing through the optical elements of the head-up display (HUD) system and backflowing into the head-up display (HUD) system. This may cause excessive temperature, affect the display effect, and even damage certain components inside the head-up display (HUD) system.

[0036] In addition, the current imaging technology of the head-up display (HUD) system usually uses a free-form mirror to magnify the image. The light emitted by the picture generation unit (PGU) passes through the free-form mirror and finally forms an image on the windshield. However, since the light path is bidirectional, this will cause external sunlight to converge through the windshield and the free-form mirror and flow back into the picture generation unit (PGU), resulting in a very serious problem of damage caused by sunlight backflow. The head-up display system in the related technology is easily affected by sunlight backflow, which can easily cause local overheating of the head-up display system and burn the internal picture generation unit (PGU), resulting in screen burn-in.

[0037] In the related art, for the infrared light (wavelength 760nm-1mm) and ultraviolet light (wavelength 100nm-400nm) in sunlight, good isolation can be achieved through simple or single polarization elements, which can usually isolate more than 95% of the light. As for the light in the visible light (400nm-760nm) band in sunlight, the polarization element can only isolate the light in the horizontal or vertical polarization state of visible light, and half of the energy of visible light will still flow back to the image generation unit (PGU). And while using polarization elements to isolate visible light, it will also affect the light output efficiency of the head-up display system. That is, the head-up display system in the related art has poor anti-backflow capability for light in the visible light band, and the risk of sunlight backflow damaging the internal components of the head-up display system is still high.

[0038] Based on this, a head-up display device and a vehicle are provided to reduce the risk of external light entering the head-up display device and causing damage to internal components of the head-up display device.

[0039] 1 and 2 , FIG1 is a schematic diagram of the structure of a head-up display device 10 in an embodiment of the present application, and FIG2 is a simplified schematic diagram of the polarization states of the outgoing light and the backflow incident visible light after passing through various optical elements.

[0040] The head-up display device 10 provided in the present application includes a light-emitting element 1, a first reflecting element 31, a second reflecting element 32 and an optical isolator 2. Along the propagation direction of the outgoing light, the light-emitting element 1, the first reflecting element 31 and the second reflecting element 32 are sequentially arranged along the optical axis. The light-emitting element 1 is used to emit the outgoing light, and the optical isolator 2 is arranged on the light-emitting side of the light-emitting element 1. Along the propagation direction of the outgoing light, the optical isolator 2 includes a first polarizing element 21, a second polarizing element 22 and a third polarizing element 23 sequentially arranged along the optical axis. The first polarizing element 21 is arranged on the reflection surface of the first reflecting element 31, the third polarizing element 23 is arranged on the reflection surface of the second reflecting element 32, and the second polarizing element 22 is arranged between the first reflecting element 31 and the second reflecting element 32 along the propagation direction of the outgoing light.

[0041] The first polarizing element 21 is configured to receive and reflect the outgoing light emitted by the light emitting element 1 to the second polarizing element 22, the second polarizing element 22 is configured to transmit the outgoing light to the third polarizing element 23, and the third polarizing element 23 is configured to receive and reflect the outgoing light transmitted by the second polarizing element 22, so that the outgoing light emitted by the light emitting element 1 can be emitted after passing through the first polarizing element 21, the second polarizing element 22 and the third polarizing element 23 in sequence. Therefore, the optical isolator 2 will not block the normal emission of the outgoing light, and will not affect the normal display function of the head-up display device 10 of the present application.

[0042] The first polarizing element 21 is also configured to transmit external light that sequentially passes through the third polarizing element 23 and the second polarizing element 22 and then propagates to the first polarizing element 21. It can be understood that the external light, especially the external visible light, can be directly transmitted from the first polarizing element 21 after passing through the third polarizing element 23 and the second polarizing element 22, so that it will not be reflected from the reverse light path direction of the emitted light to the light emitting element 1, and thus will not cause burning damage to the light emitting element 1, that is, the visible light will not pass through the first polarizing element 21 to the light emitting element 1, and the light emitting element 1 can be protected.

[0043] It can be understood that the light emitting element 1 and the second polarizing element 22 should be located on the same side of the first reflecting element 31, so that the first reflecting element 31 can reflect the emitted light emitted by the light emitting element 1 onto the second polarizing element 22. In this way, the head-up display device 10 of the present application is simple to manufacture, and only needs to add the second polarizing element 22, and respectively set the first polarizing element 21 on the first reflecting element 31, and set the third polarizing element 23 on the second reflecting element 32, which is simple to manufacture and saves costs. It can be modified on the existing head-up display, and is highly practical.

[0044] The optical isolator 2 of the head-up display device 10 of the present application can make the outgoing light emitted by the light-emitting element 1 pass through the first polarizing element 21, the second polarizing element 22 and the third polarizing element 23 in sequence and emit, that is, the optical isolator 2 does not affect the normal display function of the head-up display device 10. At the same time, when external light, especially external visible light, flows back into the head-up display device 10, it will first pass through the third polarizing element 23 and the second polarizing element 22 in sequence, and then propagate to the first polarizing element 21 and pass through the first polarizing element 21. In this way, the external light cannot propagate to the light-emitting element 1 against the optical path of the outgoing light, so that the light-emitting element 1 cannot be damaged. That is, the head-up display device 10 of the present application can reduce the risk of external visible light entering the head-up display device 10 and causing damage to the head-up display device 10. And the present application only needs to set the first polarizing element on the first reflective element, set the third polarizing element on the second reflective element, and add the second polarizing element between the first reflective element and the second reflective element, which is simple in structure and conducive to cost saving.

[0045] Referring to FIG. 1 and in combination with FIG. 2 , the outgoing light emitted by the light emitting element 1 is in a first polarization state, the first polarization element 21 is configured to reflect the light in the first polarization state to the second polarization element 22, and transmit the light in other polarization states, the second polarization element 22 is configured to convert the outgoing light in the first polarization state into the light in the third polarization state, and to convert the light in the third polarization state into the light in the second polarization state, and the third polarization element 23 is configured to reflect the light in the third polarization state.

[0046] It can be understood that the outgoing light emitted by the light emitting element 1 is still the outgoing light in the first polarization state after passing through the first polarization element 21, and the outgoing light in the first polarization state then passes through the second polarization element 22, and is converted into the outgoing light in the third polarization state by the second polarization element 22. The third polarization element 23 can reflect the light in the third polarization state, so that the outgoing light in the third polarization state can smoothly pass through the third polarization element 23. In this way, the outgoing light can pass through the first polarization element 21, the second polarization element 22 and the third polarization element 23 in sequence, and be smoothly emitted, and finally it is in the third polarization state.

[0047] The second polarizing element 22 can also convert the light in the third polarization state into the light in the second polarization state. It can be understood that when the visible light in the natural light flows back into the head-up display device 10, it first passes through the third polarizing element 23, wherein only the light in the third polarization state can be reflected by the third polarizing element 23 to the second polarizing element 22. The second polarizing element 22 converts the received light in the third polarization state into light in the second polarization state. After that, the light in the second polarization state is transmitted to the first polarizing element 21 and transmitted by the first polarizing element 21, so that it cannot flow back against the optical path of the outgoing light and propagate to the light-emitting element 1, thereby not causing damage to the light-emitting element 1. The head-up display device 10 of the present application can reduce the risk of external visible light entering the head-up display device 10 and causing damage to the head-up display device 10.

[0048] In some embodiments, the first reflective element 31 includes a plane reflector, and the second reflective element 32 includes a free-form reflector. That is, the first reflective element 31 can be a plane reflector in the head-up display device 10, or the first reflective element 31 can be a fixed mirror in the head-up display device 10, and the second reflective element 32 can be a movable curved reflector in the head-up display device 10. In some embodiments, the first reflective element 31 can also be a curved reflector, which is not limited here. It is only necessary that along the propagation path of the outgoing light, the first reflective element 31 is closer to the light-emitting element 1 than the second reflective element 32. In this way, it is convenient to arrange the first polarizing element 21 on the first reflective element 31, and the third polarizing element 23 on the second reflective element 32, so that the outgoing light passes through the first polarizing element 21 first, and the visible light that flows back into the device passes through the third polarizing element 23 first, which is beneficial for the first polarizing element 21 and the third polarizing element 23 to realize their corresponding polarization functions. At the same time, it is simple to make, cost-saving, and highly practical.

[0049] In some embodiments, with reference to FIG3 , FIG3 is a schematic diagram of the structure of the Faraday rotator of the present application. The second polarization element 22 includes a Faraday rotator, and the second polarization element 22 rotates the polarization of the light by 45°. In this way, with reference to FIG2 , the second polarization element 22 can convert the outgoing light in the first polarization state into the light in the third polarization state, and at the same time, the second polarization element 22 can convert the natural light that flows back and is converted by the third polarization element 23 into the light in the second polarization state. It can be understood that the phase difference between the light in the first polarization state and the light in the third polarization state is 45°, the phase difference between the light in the third polarization state and the light in the second polarization state is 45°, and the phase difference between the light in the first polarization state and the light in the second polarization state is 90°. With such a design, the polarization direction of the light in the first polarization state is perpendicular to the polarization direction of the light in the second polarization state, so that a simple polarization element can be used to select between the light in the first polarization state and the light in the second polarization state, that is, the light in the first polarization state is selectively passed, and the light in the second polarization state is blocked, so as to prevent the natural light that has been converted to the second polarization state from flowing back into the light-emitting element 1 and damaging the light-emitting element 1. This is conducive to the diversification of the selection of the first polarization element 21, the convenience of selecting a low-cost polarization element, the cost saving, and the further reduction of the need for modification and production.

[0050] In some embodiments, the angle between the reflection axis of the first polarizing element 21 and the reflection axis of the third polarizing element 23 is 45°. It can be understood that the phase difference between the light of the first polarization state and the light of the third polarization state is also 45°. In this way, the outgoing light in the first polarization state can pass through the third polarizing element 23 smoothly after being converted into the light of the third polarization state by the second polarizing element 22, and the third polarizing element 23 will not block the outgoing light, so that the outgoing light emitted by the light emitting element 1 can pass through the optical isolator 2 smoothly, that is, the optical isolator 2 does not affect the normal display function of the head-up display device 10. The visible light in the natural light that flows back is converted into the light of the third polarization state by the third polarizing element 23, and then deflected by 45° by the second polarizing element 22. At this time, the polarization direction of the visible light that flows back is exactly 90° different from the reflection axis of the first polarizing element 21, so that it cannot pass through the first polarizing element 21, and is then blocked by the first polarizing element 21, and will not enter the light emitting element 1, reducing the risk of damage to the light emitting element 1.

[0051] In some embodiments, as shown in FIG. 3 , the second polarizing element 22 includes a body 221 and a coil 222 wound around the body 221, the coil 222 is used to provide a magnetic field parallel to the optical axis to the body 221, and the material of the body 221 includes a magneto-optical material. The polarization rotation angle β of the second polarizing element 22 satisfies: β=VBd, where V is the Verdet constant of the body 221, that is, the magneto-optical material, B is the magnetic field in the propagation direction of the outgoing light, and d is the length of the body 221 along the propagation direction of the outgoing light. According to the wavelength of the operation of the second polarizing element 22, which is the wavelength of the visible light band in this embodiment, the corresponding magneto-optical material is selected to determine the Verdet constant V of the magneto-optical material. According to the size of the head-up display device 10, or the optical path space of the outgoing light in the head-up display device 10, a suitable length d of the body 221 along the propagation direction of the outgoing light is selected, and finally the power supply size and the number of windings of the control coil 222 are controlled so that the coil 222 provides the corresponding magnetic field B, so that the second polarizing element 22 can realize the conversion of the polarization state of the light.

[0052] In some embodiments, the first polarizing element 21 includes a first reflective polarizer or a first cold mirror film, so that the polarization function of the first polarizing element 21 can be achieved by directly attaching a reflective polarizer to the first reflective element 31, or directly coating a corresponding cold mirror film on the first reflective element 31, thereby further simplifying the production steps, reducing the production cost, and facilitating cost savings.

[0053] In some embodiments, the third polarizing element 23 includes a second reflective polarizer or a second cold mirror film. Correspondingly, the polarizing function of the third polarizing element 23 can be realized by directly attaching a reflective polarizer to the second reflective element 32, or directly coating the second reflective element 32 with a corresponding cold mirror film, which further simplifies the manufacturing steps, reduces the manufacturing cost, and helps save costs.

[0054] In some embodiments, the head-up display device 10 includes a housing, a light emitting member disposed on the housing, and a dustproof film 4. The light emitting element 1 and the optical isolator 2 are both disposed in the housing, and the light emitted by the light emitting element 1 passes through the optical isolator 2 and then is emitted through the light emitting member; the dustproof film 4 is disposed on the light emitting member. The dustproof film 4 plays a dustproof role, which is beneficial to improving the protection of the head-up display device 10, especially the protection of its internal optical elements. At the same time, the dustproof film 4 can play a preliminary role in isolating the backflow of natural light, further reducing the risk of natural light backflow damaging the head-up display device 10.

[0055] The present application also provides a vehicle, comprising the head-up display device 10 and the windshield 5 in any of the above embodiments, wherein the light emitted by the head-up display device 10 is projected onto the windshield 5 and a preset image is displayed. In contrast, natural light, such as sunlight, which flows back into the head-up display device 10 through the windshield 5 is blocked by the optical isolator 2 and does not flow back onto the light-emitting element 1, thereby reducing the risk of damage to the internal components of the head-up display device 10 by external light.

[0056] In the head-up display device 10 of the present application, the outgoing light is reflected by the first polarizing element 21, then transmitted by the second polarizing element 22, and finally reflected by the third polarizing element 23, so as to be emitted from the head-up display device 10. It does not affect the normal display function of the head-up display device 10. At the same time, when natural light, especially visible light, flows back into the head-up display device 10, it will first pass through the third polarizing element 23 and the second polarizing element 22 in sequence, and then pass through the first polarizing element 21 when it propagates to the first polarizing element 21. It can be understood that the external light passes through the first polarizing element 21, and will not be reflected by the first polarizing element 21 against the light path of the outgoing light to the light-emitting element 1, so that the light-emitting element 1 cannot be damaged. That is, the head-up display device 10 of the present application can reduce the risk of external visible light entering the head-up display device 10 and causing damage to the head-up display device 10.

[0057] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0058] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A head-up display device, characterized in that: The head-up display device comprises: A light emitting element for emitting outgoing light; A first reflecting element and a second reflecting element, wherein the first reflecting element and the second reflecting element are sequentially arranged along a propagation direction of the emergent light; and An optical isolator, comprising a first polarizing element, a second polarizing element and a third polarizing element sequentially arranged along a propagation direction of the outgoing light, wherein the first polarizing element is arranged on a reflection surface of the first reflecting element, the third polarizing element is arranged on a reflection surface of the second reflecting element, and along the propagation direction of the outgoing light, the second polarizing element is arranged between the first reflecting element and the second reflecting element; The first polarization element is configured to receive and reflect the outgoing light emitted by the light-emitting element to the second polarization element, the second polarization element is configured to transmit the outgoing light to the third polarization element, and the third polarization element is configured to receive and reflect the outgoing light transmitted by the second polarization element; and the first polarization element is also configured to transmit external light that passes through the third polarization element and the second polarization element in sequence and then propagates to the first polarization element.

2. The head-up display device according to claim 1, characterized in that: The outgoing light emitted by the light-emitting element is in a first polarization state, the first polarization element is configured to reflect light in the first polarization state and transmit light in other polarization states, the second polarization element is configured to convert the outgoing light in the first polarization state into light in a third polarization state, and to convert light in the third polarization state into light in the second polarization state, and the third polarization element is configured to reflect light in the third polarization state.

3. The head-up display device according to claim 1, characterized in that: The first reflective element includes a plane reflective mirror, and the second reflective element includes a free-form reflective mirror.

4. The head-up display device according to claim 1, characterized in that: The second polarization element comprises a Faraday rotator, and the second polarization element rotates the polarization of the light by 45°.

5. The head-up display device according to claim 4, characterized in that: The second polarization element includes a body and a coil wound around the body, the coil is used to provide a magnetic field parallel to the optical axis to the body, and the material of the body includes magneto-optical material.

6. The head-up display device according to claim 1, characterized in that: The angle between the reflection axis of the first polarizing element and the reflection axis of the third polarizing element is 45°.

7. The head-up display device according to claim 1, characterized in that: The first polarizing element includes a reflective polarizer or a cold mirror film.

8. The head-up display device according to claim 1, characterized in that: The third polarizing element includes a reflective polarizer or a cold mirror film.

9. The head-up display device according to claim 1, characterized in that: The light emitting element and the second polarizing element are located on the same side of the first polarizing element.

10. A vehicle, characterized in that: It comprises a head-up display device as claimed in any one of claims 1 to 9.

Images