Pupil expanding device, head-up display device and vehicle

Abstract

The invention relates to a pupil expanding device, head-up display equipment and a vehicle. The pupil expanding device comprises a plurality of semi-transparent and semi-reflecting mirrors, the semi-transparent and semi-reflecting mirrors are sequentially arranged in the first direction, the semi-transparent and semi-reflecting mirrors can receive light rays propagating to the semi-transparent and semi-reflecting mirrors in the first direction, and the semi-transparent and semi-reflecting mirrors can reflect and emit part of the received light rays and transmit the rest of the light rays. According to the pupil expanding device, the plurality of semi-transparent and semi-reflecting mirrors are arranged in sequence, so that the light is reflected and emitted in sequence through the plurality of semi-transparent and semi-reflecting mirrors and is partially transmitted, pupil expanding of the light in the first direction can be realized through light splitting of the plurality of semi-transparent and semi-reflecting mirrors in the first direction, and the field angle of the light passing through the pupil expanding device can be increased. Meanwhile, the plurality of semi-transparent and semi-reflecting mirrors are sequentially arranged along the first direction without occupying extra three-dimensional space, so that the occupied space is favorably reduced, and the miniaturization design of the head-up display equipment is favorably realized.

Description

Technical Field

[0001] This application relates to the technical field of head-up display, and particularly to a pupil expansion device, a head-up display device, and a vehicle. Background Art

[0002] A head-up display device usually needs to transmit the light emitted by an image generation system to a transparent screen through optical elements. In related technologies, optical elements such as optical lenses, prisms, and mirrors are often used to transmit light. However, when using the above optical elements in related technologies, the transmitted light is usually limited to a small range, that is, the viewing angle of the image is usually small, which affects the viewing experience. Moreover, using the above optical elements usually occupies a large space, which is not conducive to the miniaturization design of the head-up display device, and also easily increases the loss during the light propagation process, resulting in low light utilization rate. Summary of the Invention

[0003] Based on this, a pupil expansion device, a head-up display device, and a vehicle are provided, so that the light passing through the pupil expansion device can have a large viewing angle, which is also conducive to reducing the occupied space and facilitating the miniaturization design of the head-up display device. At the same time, it is conducive to improving the light utilization rate and increasing the display brightness.

[0004] According to one aspect of the present application, a pupil expansion device is provided. The pupil expansion device includes:

[0005] A pupil expansion lens group, including at least two semi-transmissive semi-reflective mirrors, the at least two semi-transmissive semi-reflective mirrors are arranged in sequence along a first direction, the pupil expansion lens group has a light incident side and a light exit side that face away from each other in the first direction, the semi-transmissive semi-reflective mirror is inclined to the first direction, and the light incident side is used for receiving light; and

[0006] A reflection element, arranged on the light exit side of the pupil expansion lens group, and having a reflective surface facing the pupil expansion lens group.

[0007] In one embodiment, the pupil expansion device has an imaging surface, the imaging surface is located on one side of the pupil expansion lens group in a second direction, the surface of the semi-transmissive semi-reflective mirror facing the light exit side is opposite to the reflection element in the first direction and opposite to the imaging surface in the second direction;

[0008] Wherein, the second direction is perpendicular to the first direction.

[0009] In one embodiment, the semi-transmissive semi-reflective mirror includes a substrate and a semi-transmissive semi-reflective layer, and the semi-transmissive semi-reflective layer is arranged on one side of the substrate along the first direction.

[0010] In one embodiment, along the thickness direction of the substrate, the sum h of the sizes of the substrate and the semi-transmissive semi-reflective layer satisfies: 0.5 mm ≤ h ≤ 2 mm.

[0011] In one embodiment, along the direction perpendicular to the thickness direction of the substrate, the radial dimension a of the substrate satisfies: 40 mm ≤ a ≤ 350 mm.

[0012] In one embodiment, the angle β between the plane perpendicular to the thickness direction of the substrate and the first direction satisfies: 15° ≤ β ≤ 35°.

[0013] In one embodiment, along the first direction, the distance d between two adjacent semi-transmissive semi-reflective mirrors satisfies 15 mm ≤ d ≤ 35 mm.

[0014] In one embodiment, the transmittance T of the semi-transmissive semi-reflective mirror satisfies: 60% ≤ T ≤ 85%, and the reflectance R of the semi-transmissive semi-reflective mirror satisfies: 15% ≤ R ≤ 40%.

[0015] According to another aspect of the present application, there is provided a head-up display device, including an optical engine and the pupil-expanding device described in any of the above embodiments, and the pupil-expanding device is disposed on the light-emitting side of the optical engine.

[0016] In one embodiment, the head-up display device further includes an optical collimation system, and the optical collimation system is disposed between the optical engine and the pupil-expanding device.

[0017] According to still another aspect of the present application, there is provided a vehicle, including the head-up display device described in any of the above embodiments.

[0018] For the above-mentioned pupil expansion device, the light rays incident from the light incident side into the pupil expansion lens group sequentially pass through a plurality of semi-transmissive and semi-reflective mirrors, and are reflected on at least one semi-transmissive and semi-reflective mirror. And at least some of the remaining light rays sequentially pass through a plurality of semi-transmissive and semi-reflective mirrors and then are emitted onto the reflecting element, and are reflected back onto the pupil expansion lens group by the reflecting surface of the reflecting element. Among them, some light rays are emitted after being reflected by the semi-transmissive and semi-reflective mirror, and the other part of the light rays pass through the semi-transmissive and semi-reflective mirror and enter the next semi-transmissive and semi-reflective mirror. The light rays incident on the next semi-transmissive and semi-reflective mirror are emitted after being reflected by the semi-transmissive and semi-reflective mirror. The light rays emitted after being reflected by different semi-transmissive and semi-reflective mirrors form the same image, which is equivalent to the image being replicated multiple times in the first direction, and the number of replications is equal to the number of times of being emitted after being reflected by the semi-transmissive and semi-reflective mirror. That is, by arranging a plurality of semi-transmissive and semi-reflective mirrors in sequence, the light rays are sequentially reflected and emitted through a plurality of semi-transmissive and semi-reflective mirrors, and partially transmitted. In this way, through the splitting of light in the first direction by a plurality of semi-transmissive and semi-reflective mirrors, the pupil expansion of the light rays in the first direction can be realized, thereby improving the field of view angle of the light rays passing through the pupil expansion device. At the same time, a plurality of semi-transmissive and semi-reflective mirrors can be arranged in sequence in the first direction, without occupying additional three-dimensional space, which is beneficial to reducing the occupied space and is beneficial to the miniaturized design of the head-up display device. And the setting of the reflecting element can reflect part of the light rays that finally pass through a plurality of semi-transmissive and semi-reflective mirrors back into the plurality of semi-transmissive and semi-reflective mirrors, and are reflected and emitted again through a plurality of semi-transmissive and semi-reflective mirrors, so that its pupil is further expanded in the first direction, which is beneficial to improving the utilization rate of light rays and increasing the brightness of the displayed image. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the light rays emitted by the optical engine passing through the pupil expansion device and imaging in an embodiment of the present application.

[0020] Figure 2 It is a schematic diagram of the imaging of the light rays passing through the pupil expansion device in an embodiment of the present application.

[0021] Figure 3 It is a schematic structural diagram of the head-up display device in an embodiment of the present application.

[0022] Description of the reference numerals in the drawings:

[0023] 10. Head-up display device;

[0024] 100. Pupil expansion device; 110. Semi-transmissive and semi-reflective mirror; 120. Reflecting element;

[0025] 200. Optical engine; 300. Optical collimation system; 400. Windshield;

[0026] F1. First direction. Detailed Embodiment

[0027] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a thorough 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 departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0028] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application 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 thus should not be construed as a limitation on the present application.

[0029] In addition, if terms such as "first" and "second" appear, these terms are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0030] In the present application, unless otherwise clearly specified and limited, if terms such as "install", "connect", "couple", "fix", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0031] In this application, unless otherwise clearly specified and defined, when a first feature is described as being "on" or "under" a second feature or similar descriptions, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0032] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for illustrative purposes and do not represent the only implementation.

[0033] A head-up display (HUD) generally consists of an image generation system, an optical element and a screen. The light emitted by the image generation system is projected onto the screen through the optical element, and then reflected by the screen into the driver's eyes for imaging so that the driver can view it. The head-up display can be divided into a C-HUD (Combiner-HUD) that projects onto an external transparent screen and a W-HUD (windshield-HUD) that projects onto the windshield.

[0034] However, whether it is a C-HUD or a W-HUD, it is necessary to propagate the light emitted by the image generation system through the optical element to the transparent screen. The head-up display devices in the related art usually need to use multiple optical elements, such as optical lenses, prisms and mirrors, to propagate the light emitted by the image generation system. Its display effect is easily affected by manufacturing or assembly tolerances, which easily leads to image distortion. Moreover, it relies on multiple optical elements at different positions to complete the projection and display of the image, which easily makes the head-up display device bulky. The light needs to pass through multiple optical elements, which not only increases the complexity of the system and the manufacturing process, but also causes the light intensity to gradually decay, reducing the brightness and contrast of the displayed image. In addition, the head-up display devices in the related art usually have a relatively small field of view angle for forming images, which affects the user experience.

[0035] Based on this, the present application provides a pupil expansion device, a head-up display device and a vehicle, which can perform pupil expansion propagation on the light emitted by the image generation unit, increase its field of view angle, and is also conducive to simplifying the complexity of the head-up display device and facilitating the miniaturization design of the head-up display device.

[0036] Refer to Figure 1 as shown Figure 1 This is a schematic structural diagram of the light emitted by the optical engine 200 passing through the pupil expander 100 and imaging in an embodiment of the present application. The pupil expander 100 provided in the present application includes a pupil expander lens group and a reflecting element 120. The pupil expander lens group includes at least two semi-transmissive semi-reflective mirrors 110, and the at least two semi-transmissive semi-reflective mirrors 110 are arranged in sequence along the first direction F1. The pupil expander lens group has an incident light side and an emergent light side that face away from each other in the first direction F1. The semi-transmissive semi-reflective mirror 110 is inclined to the first direction F1, and the incident light side is used to receive light. It can be understood that the semi-transmissive semi-reflective mirror 110 can receive the light propagating along the first direction F1 to the incident light side of the semi-transmissive semi-reflective mirror 110, and the semi-transmissive semi-reflective mirror 110 can reflect and emit part of the received light, and transmit at least part of the remaining light.

[0037] The reflecting element 120 is arranged on the emergent light side of the plurality of semi-transmissive semi-reflective mirrors 110 and has a reflective surface facing the pupil expander lens group. It can be understood that the reflecting element 120 is used to reflect the light emitted by the pupil expander lens group back to the pupil expander lens group. As the light passes through the plurality of semi-transmissive semi-reflective mirrors 110 in sequence, at least part of the light will finally pass through the plurality of semi-transmissive semi-reflective mirrors 110 and propagate out. The setting of the reflecting element 120 can reflect the part of the light that finally passes through the plurality of semi-transmissive semi-reflective mirrors 110 back into the plurality of semi-transmissive semi-reflective mirrors 110, and then be reflected and emitted again through the plurality of semi-transmissive semi-reflective mirrors 110, further expanding the pupil along the first direction F1, which is beneficial to improving the utilization rate of light and increasing the brightness of the displayed image.

[0038] By arranging the plurality of semi-transmissive semi-reflective mirrors 110 in sequence, the light is reflected and emitted in sequence through the plurality of semi-transmissive semi-reflective mirrors 110 and partially transmitted. The light incident from the incident light side into the pupil expander lens group passes through the plurality of semi-transmissive semi-reflective mirrors 110 in sequence, and is reflected on at least one semi-transmissive semi-reflective mirror 110, and at least part of the remaining light passes through the plurality of semi-transmissive semi-reflective mirrors 110 and then exits to the reflecting element 120, and is reflected back to the pupil expander lens group by the reflective surface of the reflecting element 120. Among them, part of the light is reflected and emitted by the semi-transmissive semi-reflective mirror 110, and the other part of the light passes through the semi-transmissive semi-reflective mirror 110 and enters the next semi-transmissive semi-reflective mirror 110. The light incident on the next semi-transmissive semi-reflective mirror 110 is reflected and emitted by the semi-transmissive semi-reflective mirror 110. The light reflected and emitted by different semi-transmissive semi-reflective mirrors 110 forms the same image, which is equivalent to the image being replicated multiple times in the first direction F1, and the number of replications is equal to the number of times of being reflected and emitted by the semi-transmissive semi-reflective mirror 110.

[0039] Through the splitting of light by multiple semi-transmissive semi-reflective mirrors 110 along the first direction F1 in this way, it is possible to achieve pupil expansion of the light along the first direction F1, thereby improving the field of view angle of the light passing through the pupil expansion device 100. At the same time, the multiple semi-transmissive semi-reflective mirrors 110 can be arranged in sequence along the first direction F1, without occupying additional three-dimensional space, which is beneficial to reducing the occupied space and facilitating the miniaturized design of the head-up display device 10. And the setting of the reflection element 120 can reflect part of the light that finally passes through the multiple semi-transmissive semi-reflective mirrors back into the multiple semi-transmissive semi-reflective mirrors, and then reflect and emit it again through the multiple semi-transmissive semi-reflective mirrors, so that it is further expanded in the first direction, which is beneficial to improving the utilization rate of light and increasing the brightness of the displayed image.

[0040] For example, three semi-transmissive semi-reflective mirrors 110 are arranged in sequence along the first direction F1, such as Figure 1 , the light emitted by the optical engine 200 is emitted along the first direction F1 and enters the semi-transmissive semi-reflective mirror 110 closest to the optical engine 200 among the three semi-transmissive semi-reflective mirrors 110. This semi-transmissive semi-reflective mirror 110 reflects and emits part of the received light, and transmits the remaining part of the received light to the next semi-transmissive semi-reflective mirror 110. Then the next semi-transmissive semi-reflective mirror 110 receives this part of the light, reflects and emits part of the received light, and transmits the remaining part of the received light to the last semi-transmissive semi-reflective mirror 110 among the three semi-transmissive semi-reflective mirrors 110. Similarly, the last semi-transmissive semi-reflective mirror 110 also emits part of the received light and transmits the remaining part of the received light. In this way, successive splitting of the light emitted by the optical engine 200 in the first direction F1 is achieved, or in other words, pupil expansion in the first direction F1, thereby improving the field of view angle of the light passing through the pupil expansion device 100.

[0041] In this embodiment, the number of semi-transmissive semi-reflective mirrors 110 is not limited, and two semi-transmissive semi-reflective mirrors 110 can be set, or the number of semi-transmissive semi-reflective mirrors 110 can be increased. Such as Figure 1 , when applied to a vehicle, when the light passes through the first semi-transmissive semi-reflective mirror 110, part of the light will be reflected to the windshield 400 of the vehicle, and the remaining part of the light will penetrate to the next semi-transmissive semi-reflective mirror 110. After this part of the light enters the next semi-transmissive semi-reflective mirror 110, it will undergo partial penetration and partial reflection again. By repeating this process, the light emitted by the optical engine 200 is replicated multiple times in the multiple semi-transmissive semi-reflective mirrors 110 along the first direction F1, and each exit pupil is the same image, thereby achieving a one-dimensional pupil expansion effect. After the light is reflected to the windshield 400, it is then reflected by the windshield 400 to the human eye and forms an image on the human eye, so that the driver can see the image when moving in the first direction F1. Using this pupil expansion technology, the eye box size can be expanded, enabling users with different pupil distances to see the image.

[0042] In this embodiment, the semi-transmissive and semi-reflective mirror 110 can reflect part of the light and transmit at least part of the remaining light. It can be understood that there is actually also light loss during the propagation process, which will not be elaborated here.

[0043] In this embodiment, the reflecting element 120 can be a curved mirror, and its curved surface can be a concave surface, or it can be a spherical surface, an aspherical surface, or other curved surfaces designed according to system and display requirements, and no excessive requirements are made here.

[0044] In some embodiments, the pupil expander device 100 has an imaging surface, the imaging surface is located on one side of the pupil expander lens group in the second direction, the surface of the semi-transmissive and semi-reflective mirror 110 facing the light-emitting side is opposite to the reflecting element 120 in the first direction F1, and the semi-transmissive and semi-reflective mirror 110 is opposite to the imaging surface in the second direction. Wherein, the second direction is perpendicular to the first direction. In this way, the semi-transmissive and semi-reflective mirror 110 can reflect part of the light received and propagating in the first direction to the imaging surface propagating in the second direction. In this embodiment, the imaging surface can coincide with the windshield 400 or the display screen, which will not be elaborated here.

[0045] In some embodiments, the semi-transmissive and semi-reflective mirror 110 includes a substrate and a semi-transmissive and semi-reflective layer, and the semi-transmissive and semi-reflective layer is provided on one side of the substrate along the first direction F1. The semi-transmissive and semi-reflective layer can be deposited on the substrate by a coating process. Moreover, the semi-transmissive and semi-reflective layers of multiple semi-transmissive and semi-reflective mirrors 110 can be provided on the same side or different sides of the corresponding substrates along the first direction F1, and can be designed according to actual needs to improve design flexibility and the applicability of the pupil expander device 100. It can be understood that the design of the substrate and the semi-transmissive and semi-reflective layer makes the semi-transmissive and semi-reflective mirror 110 a plate-like structure. In this way, compared with the semi-transmissive and semi-reflective mirror with a prism structure in the related art, the semi-transmissive and semi-reflective mirror 110 of the present application has the advantages of cost saving, space saving, and being conducive to the miniaturization design of the pupil expander device 100.

[0046] In this embodiment, the material of the substrate can be glass or an optical grade plastic material. Selecting glass can make the semi-transmissive and semi-reflective mirror 110 have better transparency, higher hardness, and better corrosion resistance. Using an optical grade plastic material can make the semi-transmissive and semi-reflective mirror 110 have the advantages of light weight, better impact resistance, strong resistance to sudden temperature changes, and better light transmittance. It can also be set such that the substrates of some of the multiple semi-transmissive and semi-reflective mirrors 110 are made of glass, and the substrates of the other part of the semi-transmissive and semi-reflective mirrors 110 are made of optical grade plastic materials. Other materials of the substrate can also be used according to actual needs, and no excessive restrictions are made here.

[0047] In some embodiments, along the thickness direction of the substrate, the sum of the sizes of the substrate and the semi-transmissive semi-reflective layer, or the size h of the semi-transmissive semi-reflective mirror 110, satisfies: 0.5 mm ≤ h ≤ 2 mm. It can be understood that the plate-shaped semi-transmissive semi-reflective mirror 110 of the present application is beneficial to greatly reducing the size of the semi-transmissive semi-reflective mirror 110, and the size of the semi-transmissive semi-reflective mirror 110 of the present application satisfies the above range, which is beneficial to obtaining better reflection and transmission stability of the semi-transmissive semi-reflective mirror 110 and is beneficial to providing stable support for the semi-transmissive semi-reflective layer through the substrate. That is, satisfying the above range is beneficial to enabling the semi-transmissive semi-reflective mirror 110 to have a better reflection and transmission effect while saving occupied space and facilitating the miniaturized design of the pupil expansion device 100.

[0048] In some embodiments, along the direction perpendicular to the thickness direction of the substrate, the radial dimension a of the substrate satisfies: 40 mm ≤ a ≤ 350 mm. It can be understood that the substrate of the present application can be a structure of various shapes, such as a cuboid or a wedge-shaped cuboid, etc. The projection shape of the substrate on the plane perpendicular to the thickness direction of the substrate can be a circle, a square or a rectangle, etc., and no more restrictions are made here. It only needs to satisfy the above relationship for its radial dimension a along the direction perpendicular to the thickness direction of the substrate.

[0049] For example, when the projection shape of the substrate on the plane perpendicular to the thickness direction of the substrate is a circle, the diameter of the circle is a and satisfies the above range. If the projection shape of the substrate on the plane perpendicular to the thickness direction of the substrate is a rectangle, both the length and width of the rectangle need to satisfy the above range. In this way, the substrate has a better size range, which is beneficial to enabling the light emitted by the optical engine 200 to be more comprehensively transmitted and reflected, improving the utilization rate of light, and at the same time enabling the substrate size to be within a better range, which is beneficial to the miniaturized design of the pupil expansion device 100.

[0050] In some embodiments, the angle β between the plane perpendicular to the thickness direction of the substrate and the first direction F1 satisfies: 15° ≤ β ≤ 35°. That is, the semi-transmissive semi-reflective surface of the semi-transmissive semi-reflective mirror 110 can be inclined with respect to the first direction F1, and its inclination angle is within the range of 15° to 35°. Satisfying the above range is beneficial to relatively reducing the distance between adjacent two semi-transmissive semi-reflective mirrors 110 when arranging multiple semi-transmissive semi-reflective mirrors 110, and does not affect or block the exit of the reflected light of any semi-transmissive semi-reflective mirror 110. Thus, while facilitating the normal reflection and propagation of light to the windshield 400, it is beneficial to reducing the size of the pupil expansion device 100 and facilitating the miniaturized design of the pupil expansion device 100.

[0051] In some embodiments, along the first direction F1, the distance d between two adjacent semi-transparent and semi-reflective mirrors 110 satisfies 15 mm ≤ d ≤ 35 mm. When the above range is met, the distance between two adjacent semi-transparent and semi-reflective mirrors 110 can be adjusted according to demand, and the distance between the semi-transparent and semi-reflective mirrors 110 is relatively close, which is conducive to further reducing the size of the pupil expansion device 100.

[0052] In some embodiments, the transmittance T of the semi-transparent and semi-reflective mirror 110 satisfies: 60%≤T≤85%, and the reflectance R of the semi-transparent and semi-reflective mirror 110 satisfies: 15%≤R≤40%. That is, the semi-transparent and semi-reflective mirror 110 can reflect 15% to 40% of the light, and transmit 60% to 85% of the light to the next semi-transparent and semi-reflective mirror 110 or the reflective element 120, so that the light can be expanded along the first direction F1. Satisfying the above range is conducive to making the light have a uniform pupil expansion effect after the light is split and expanded layer by layer, so that the uniformity of the displayed imaging is better and the imaging quality is higher.

[0053] In some embodiments, see Figure 2 As shown, Figure 2 Schematic diagram of imaging after light passes through a pupil expansion device in an embodiment of the present application. In this embodiment, the pupil expansion device 100 of the present application includes three semi-transparent and semi-reflective mirrors 110 arranged in sequence along the first direction F1, and the thickness of the three semi-transparent and semi-reflective mirrors 110 is 0.5 mm. The reflectivity of the first semi-transparent and semi-reflective mirror 110 or the semi-transparent and semi-reflective mirror 110 closest to the optical machine 200 is 31.5%, the reflectivity of the second semi-transparent and semi-reflective mirror 110 or the semi-transparent and semi-reflective mirror 110 located in the middle position is 22%, and the reflectivity of the third semi-transparent and semi-reflective mirror 110 or the semi-transparent and semi-reflective mirror 110 closest to the reflective element is 16%. In this way, combined with Figure 2 As shown, it can be seen that the image formed by the light after passing through the pupil expansion device 100 in this embodiment has a higher brightness, and the brightness of the image is relatively uniform, which obviously has a better imaging quality.

[0054] In some embodiments, the semi-transparent and semi-reflective mirror 110 also includes an anti-reflective coating layer, which is provided on the substrate and is located on the side of the substrate away from the semi-transparent and semi-reflective layer. The anti-reflective coating (AR Coating) can be coated on the substrate using a coating process to reduce the reflection loss of light by the semi-transparent and semi-reflective mirror 110, thereby improving the transmittance and optical performance.

[0055] In some embodiments, the pupil expansion device 100 of the present application can also set at least one reflector between multiple semi-transparent and semi-reflective mirrors 110 or between the semi-transparent and semi-reflective mirrors 110 and the reflective element 120 according to actual needs, so as to fold the optical path and help reduce the overall volume.

[0056] The present application also provides a head-up display device 10, including an optical engine 200 and the pupil expansion device 100 described in any of the above embodiments. The pupil expansion device 100 is disposed on the light-emitting side of the optical engine 200. As Figure 1 , the optical engine 200 emits light rays along a first direction F1, and the pupil expansion device 100 is disposed on one side of the optical engine 200 along the first direction F1. Thus, after the light rays emitted by the optical engine 200 and propagating along the first direction F1 enter the pupil expansion device 100, pupil expansion along the first direction F1 is achieved through a plurality of semi-transmissive and semi-reflective mirrors 110 sequentially arranged along the first direction F1, thereby increasing the field of view angle of the display light rays and expanding the eye box size, so that the user can see the image when moving in the first direction F1.

[0057] In some embodiments, the optical engine 200 can be a thin film transistor liquid crystal display (TFT-LCD), a mini light-emitting diode (Mini-LED), a micro light-emitting diode (Micro-LED), or a digital light processing (DLP) device, and the position and angle of the optical engine 200 may be adjusted according to system design and display requirements, such as increasing the tilt or rotation angle relative to the pupil expansion device 100.

[0058] TFT-LCD (Thin Film Transistor Liquid Crystal Display) is a liquid crystal display screen realized through thin film transistor technology. A thin film transistor (TFT) is provided on each pixel of the liquid crystal display screen, which can effectively overcome crosstalk during non-selection, making the static characteristics of the display liquid crystal screen independent of the number of scan lines. Therefore, the image quality is greatly improved, and it has advantages such as high resolution, high color reproduction degree, and low energy consumption. The head-up display device 10 of the present application adopts TFT-LCD, which can greatly improve the display effect of the head-up display device 10.

[0059] Mini-LED refers to an LED chip with a size in the order of 100 micrometers, and the chip pitch is between 0.1 mm and 1 mm. It has advantages such as high resolution, high contrast ratio, low latency, and low power consumption. The head-up display device 10 of the present application adopts Mini-LED, which is beneficial to having a better display effect.

[0060] Micro-LED refers to an LED chip with a size in the order of 1 - 100 micrometers. It directly uses tiny LED chips as display pixels, and these tiny LED chips are transferred to a substrate through a mass transfer technology to form a display array. The head-up display device 10 of the present application adopts Micro-LED, which can have the advantages of high efficiency, high contrast ratio, high resolution, and fast response.

[0061] The principle of DLP technology is to digitally process the image signal first, and then project light through a digital micromirror device (DMD), which can provide a display effect with high contrast and high resolution. The head-up display device 10 of the present application adopts DLP technology and can have display advantages such as high clarity, high brightness, and rich colors.

[0062] In some embodiments, refer to Figure 3 as shown Figure 3 It is a schematic structural diagram of the head-up display device 10 in an embodiment of the present application. The head-up display device 10 further includes an optical collimation system 300, and the optical collimation system 300 is disposed between the optical engine 200 and the pupil expander 100. In this embodiment, the imaging light rays emitted by the optical engine 200 are first collimated by the optical collimation system 300 and then propagated to the pupil expander 100. The optical collimation system 300 can modulate the imaging light rays, which is beneficial to improving the quality of the imaging light rays and the display effect of the head-up display device 10. In this embodiment, the optical engine 200 can also be placed in other positions, and the light rays emitted by the optical engine 200 can be conducted to the light incident side of the pupil expander 100 through a reflection optical path.

[0063] In some embodiments, the head-up display device 10 of the present application can also, according to actual needs, set at least one mirror between multiple optical elements. The mirror can be a plane mirror or other reflection structures, so as to be able to fold the optical path and facilitate reducing the overall volume.

[0064] In some embodiments, the head-up display device 10 further includes a display screen, that is, the pupil expander 100 of the present application can be applied to a C-HUD equipped with an external transparent screen. The imaging light rays emitted by the optical engine 200 are incident on the display screen after passing through the pupil expander 100, and then reflected by the display screen and imaged in the driver's eyes. Combined with the C-HUD, the head-up display device 10 of the present application has advantages such as flexible installation method and low cost. The pupil expander 100 of the present application can also be applied to a W-HUD. When applied to a W-HUD, the display screen of the head-up display device 10 is the windshield 400 of the vehicle. The imaging light rays emitted by the optical engine 200 are incident on the windshield 400 of the vehicle after passing through the pupil expander 100, and then reflected by the windshield 400 and imaged in the driver's eyes. Combined with the W-HUD, the head-up display device 10 of the present application has advantages such as good display effect, high safety, and the ability to display richer information. Among them, the shape of the windshield 400 can be planar, arc-shaped or wedge-shaped, and no more restrictions are made here.

[0065] The pupil expansion device 100 of the present application can also be applied to the augmented reality head-up display technology (Augmented Reality-HUD, AR-HUD). Combining with AR technology, virtual information is fused with the real driving scene, and information such as navigation and advanced driver assistance system (ADAS) is directly projected onto the windshield 400 and superimposed on the actual road conditions for display. Thus, the display effect of the head-up display device 10 of the present application can be made more abundant and complete, the conversion process of the line of sight focus can be reduced, potential safety hazards can be lowered, and driving safety can be improved.

[0066] The pupil expansion device 100 and the head-up display device 10 of the present application are arranged by sequentially arranging a plurality of semi-transmissive and semi-reflective mirrors 110, so that light is sequentially reflected and emitted through the plurality of semi-transmissive and semi-reflective mirrors 110 and partially transmitted. In this way, through the spectral splitting of the plurality of semi-transmissive and semi-reflective mirrors 110 along the first direction, pupil expansion along the first direction F1 can be achieved, thereby improving the field of view angle of the light passing through the pupil expansion device 100. At the same time, the plurality of semi-transmissive and semi-reflective mirrors 110 only need to be arranged in sequence along the first direction F1, without occupying additional three-dimensional space, which is beneficial to reducing the occupied space and conducive to the miniaturization design of the head-up display device 10.

[0067] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope recorded in this specification.

[0068] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A pupil expansion device, characterized in that: The pupil expansion device comprises: A pupil dilating lens set, comprising at least two semi-transparent and semi-reflective mirrors, wherein the at least two semi-transparent and semi-reflective mirrors are arranged in sequence along a first direction, the pupil dilating lens set has a light entrance side and a light exit side opposite to each other in the first direction, the semi-transparent and semi-reflective mirrors are inclined in the first direction, and the light entrance side is used to receive light; and The reflective element is arranged on the light-emitting side of the pupil dilating lens assembly and has a reflective surface facing the pupil dilating lens assembly.

2. The pupil expansion device according to claim 1, characterized in that: The pupil expansion device has an imaging surface, the imaging surface is located on one side of the pupil expansion lens group in the second direction, and the surface of the semi-transparent and semi-reflective mirror facing the light-emitting side is opposite to the reflective element in the first direction and opposite to the imaging surface in the second direction; The second direction is perpendicular to the first direction.

3. The pupil expansion device according to claim 1, characterized in that: The semi-transparent and semi-reflective mirror comprises a substrate and a semi-transparent and semi-reflective layer, and the semi-transparent and semi-reflective layer is arranged on one side of the substrate along the first direction.

4. The pupil expansion device according to claim 3, characterized in that: Along the thickness direction of the substrate, the sum h of the dimensions of the substrate and the semi-transmissive and semi-reflective layer satisfies: 0.5 mm ≤ h ≤ 2 mm.

5. The pupil expansion device according to claim 3, characterized in that: Along a direction perpendicular to the thickness direction of the substrate, a radial dimension a of the substrate satisfies: 40 mm ≤ a ≤ 350 mm.

6. The pupil expansion device according to claim 3, characterized in that: An angle β between a plane perpendicular to the thickness direction of the substrate and the first direction satisfies: 15°≤β≤35°.

7. The pupil expansion device according to claim 1, characterized in that: Along the first direction, a distance d between two adjacent semi-transparent and semi-reflective mirrors satisfies 15 mm ≤ d ≤ 35 mm.

8. The pupil expansion device according to claim 1, characterized in that: The transmittance T of the semi-transparent and semi-reflective mirror satisfies: 60%≤T≤85%, and the reflectivity R of the semi-transparent and semi-reflective mirror satisfies: 15%≤R≤40%.

9. A head-up display device, characterized in that: It comprises an optical machine and a pupil expansion device as claimed in any one of claims 1 to 8, wherein the pupil expansion device is arranged on the light output side of the optical machine.

10. The head-up display device according to claim 9, characterized in that: The head-up display device also includes an optical collimation system, which is arranged between the optical machine and the pupil expansion device.

11. A vehicle, characterized in that: Comprising a head-up display device as described in any one of claims 9-10.

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