Display device and optical system

Abstract

The present disclosure relates to a display device and an optical system, belonging to the technical field of display, the display device comprising: a first display unit arranged in a first light path and emitting first image light; a second display unit arranged in a second light path and emitting second image light; an imaging unit arranged in the first light path and the second light path, the imaging unit receiving and reflecting the first image light to form a first image from the first image light, and receiving and reflecting the second image light to form a second image from the second image light, wherein an object distance corresponding to the first light path is greater than an equivalent focal length corresponding to the first light path, and an object distance corresponding to the second light path is less than an equivalent focal length corresponding to the second light path. Thus, the display device has both HUD function and VPA function, and it can be manufactured to a smaller volume.

Description

Technical Field

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

[0002] The in-vehicle virtual personal assistant (VPA) can interact with drivers and passengers through technologies such as voice recognition and image display to provide functions such as entertainment, navigation, and vehicle control.

[0003] Existing VPAs typically include a display unit installed in the center console of the vehicle. This display unit includes a screen facing inwards to interact with the driver and passengers through the image information displayed on the screen and the built-in sound system.

[0004] However, the display device installed in the center console of the car will take up interior space and affect the interior layout. Summary of the Invention

[0005] This section provides a general overview of this disclosure, rather than a full disclosure of the entire scope or all features of this disclosure.

[0006] According to one aspect of this disclosure, a display device is provided. The display device includes a first display unit, a second display unit, and an imaging unit. The first display unit is disposed in a first optical path and emits first image light rays. The second display unit is disposed in a second optical path and emits second image light rays. The imaging unit is disposed in both the first and second optical paths, and receives and reflects the first image light rays to form a first image, and receives and reflects the second image light rays to form a second image. The object distance corresponding to the first optical path is greater than the equivalent focal length corresponding to the first optical path, and the object distance corresponding to the second optical path is less than the equivalent focal length corresponding to the second optical path.

[0007] According to another aspect of this disclosure, an optical system is also provided. This optical system includes a display device and a reflective imaging unit as described in embodiments of this disclosure. The reflective imaging unit is located on the light-emitting side of the display device for receiving and reflecting light emitted from the display device.

[0008] According to the above technical solution, by setting the imaging unit of the display device in the first optical path and the second optical path, and making the object distance corresponding to the first optical path greater than the equivalent focal length corresponding to the first optical path, and the object distance corresponding to the second optical path less than the equivalent focal length corresponding to the second optical path, the display device can simultaneously have HUD function and VPA function. Moreover, the display device can be manufactured in a smaller size, thereby allowing the display device to be arranged in the IP, thus saving vehicle interior space and improving the flexibility of vehicle interior layout. Attached Figure Description

[0009] The features and advantages of embodiments of the present disclosure will become more readily understood from the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be enlarged or reduced to show details of specific components. In the drawings:

[0010] Figure 1 This is a schematic diagram of a display device according to a first embodiment of the present disclosure.

[0011] Figure 2 This is a schematic diagram of a display device according to a second embodiment of the present disclosure.

[0012] Figure 3 This is a schematic diagram of a display device according to a third embodiment of the present disclosure.

[0013] Figure 4 This is a schematic diagram of a display device according to the fourth embodiment of the present disclosure.

[0014] Figure 5 This is a schematic diagram of a display device according to the fifth embodiment of the present disclosure.

[0015] Figure 6 This is a schematic diagram of a display device according to the sixth embodiment of the present disclosure.

[0016] Figure 7 This is a schematic diagram of a display device according to the seventh embodiment of the present disclosure.

[0017] Figure 8 This is a schematic diagram of a display device according to the eighth embodiment of the present disclosure.

[0018] Figure 9 This is a schematic diagram of a display device according to the ninth embodiment of the present disclosure.

[0019] Figure 10 This is a schematic diagram of an optical system according to an embodiment of the present disclosure.

[0020] Figure 11 This is a schematic diagram of an optical system according to another embodiment of the present disclosure.

[0021] In the accompanying drawings, the same or corresponding technical features or components are represented by the same or corresponding reference numerals. Detailed Implementation

[0022] The present disclosure will now be described in detail with reference to the accompanying drawings and exemplary embodiments. It should be noted that the following detailed description of the present disclosure is for illustrative purposes only and is not intended to limit the scope of the disclosure.

[0023] It should be noted that, for clarity, not all features of a particular embodiment are described or shown in the specification and drawings. Furthermore, to avoid unnecessary details obscuring the technical solutions of interest in this disclosure, only the device structure closely related to the technical solutions of this disclosure is described and shown in the specification and drawings, while other details that are not closely related to the technical content of this disclosure and are known to those skilled in the art are omitted.

[0024] As mentioned earlier, since the VPA display device is usually installed in the center console of the vehicle, which would take up space in the vehicle, the inventors envisioned that the display device be placed inside the instrument panel (IP).

[0025] However, head-up display (HUD) devices are typically also installed within the IP (Installation Equipment) to project images carrying information such as vehicle and road conditions onto the vehicle's windshield, thus creating an image displaying this information in front of the driver. Due to limited space within the IP, it is difficult to simultaneously house the VPA's display device and the HUD device within the IP.

[0026] In response, the inventors envisioned combining a VPA with a HUD device to design a new display device. This display device would have a small size for installation within an IP (Instrument Platform); moreover, it could function as both a HUD and a VPA to display images.

[0027] Below, we will refer to Figures 1 to 9 The display device according to embodiments of the present disclosure will be described.

[0028] For example, the display device can be used in vehicles such as land vehicles (e.g., cars, trains, etc.), water vehicles (e.g., ships, etc.), and air vehicles (e.g., airplanes, etc.). However, this disclosure does not limit it.

[0029] First, refer to Figure 1 The display device 10 includes a first display unit 110, a second display unit 120, and an imaging unit 130.

[0030] The first display unit 110 is disposed in the first optical path and emits a first image light beam S1. The second display unit 120 is disposed in the second optical path and emits a second image light beam S2.

[0031] Both the first display unit 110 and the second display unit 120 are image sources that emit image light carrying image information. For example, the first display unit 110 and the second display unit 120 can be thin-film transistor liquid crystal displays (TFT-LCDs), microlight emitting diode displays (Micro-LEDs), etc.

[0032] The first optical path is the propagation path of the first image ray S1, and the second optical path is the propagation path of the second image ray S2. Since the first display unit 110 and the second display unit 120 respectively emit the first image ray S1 and the second image ray S2, the first display unit 110 is located at the starting point of the first optical path, and the second display unit 120 is located at the starting point of the second optical path.

[0033] The imaging unit 130 is disposed in the first optical path and the second optical path, and the imaging unit 130 receives and reflects the first image light S1 to form a first image P1 by the first image light S1, and receives and reflects the second image light S2 to form a second image P2 by the second image light S2.

[0034] Both the first image ray S1 and the second image ray S2 propagate through the imaging unit 130, thereby projecting the first image ray S1 and the second image ray S2 onto, for example, an object. Figure 1 The reflective imaging unit 20 of the vehicle shown (shown in dashed lines) forms a first image P1 and a second image P2, respectively.

[0035] Here, the vehicle's reflective imaging unit 20 receives and reflects image light emitted from the display device 10 to form an image. The reflective imaging unit 20 may be, for example, the windshield of the vehicle (e.g., a car windshield); or it may be a composite mirror, which may be made of, for example, glass, plastic, etc.; or it may be both a windshield and a composite mirror.

[0036] For example, when the reflective imaging unit 20 is both a windshield and a composite mirror, the imaging unit 130 projects a first image light S1 onto one of the windshield and the composite mirror to form a first image P1, and projects a second image light S2 onto the other of the windshield and the composite mirror to form a second image P2.

[0037] For the first optical path, the corresponding object distance is set to be greater than the corresponding equivalent focal length; and for the second optical path, the corresponding object distance is set to be less than the corresponding equivalent focal length.

[0038] The object distance corresponding to the first optical path is the distance from the first display unit 110 to the first non-planar working optical surface of the imaging unit 130. For example, in Figure 1 In the first optical path, the object distance is the distance from the first display unit 110 to the working optical surface of the first reflecting unit 131, which will be mentioned below as, for example, a concave mirror. The equivalent focal length corresponding to the first optical path is the composite focal length of the optical system composed of the optical elements in the first optical path. Similarly, the object distance of the second optical path is the distance from the second display unit 120 to the first non-planar working optical surface of the imaging unit 130. The equivalent focal length corresponding to the second optical path is the composite focal length of the optical system composed of the optical elements in the second optical path.

[0039] Based on the relationship between object distance and equivalent focal length, the first image P1 is a real image, while the second image P2 is a virtual image.

[0040] Specifically, such as Figure 1 As shown, in the first optical path, the first image light ray S1 emitted from the first display unit 110 is reflected by the imaging unit 130 and enters the reflective imaging unit 20, and is then reflected by the reflective imaging unit 20 and enters the eye box 30 (i.e., the range within which the driver's eyes can move in a certain space while maintaining a clear and complete image). Since the object distance corresponding to the first optical path is greater than the equivalent focal length corresponding to the first optical path, there will be light ray S1 reflected by the reflective imaging unit 20 on the propagation path, inside the reflective imaging unit 20 (i.e., the distance between the object and the object distance is greater than the equivalent focal length of the first optical path). Figure 1 The first image P1, which is formed as a real image, is located on the right side of the central reflection imaging unit 20.

[0041] In the second optical path, the second image light ray S2 emitted from the second display unit 120 is reflected by the imaging unit 130 and enters the reflective imaging unit 20, and is then reflected by the reflective imaging unit 20 and enters the eye box 30. Since the object distance corresponding to the second optical path is smaller than the equivalent focal length corresponding to the second optical path, on the reverse extension line of the second image light ray S2 reflected by the reflective imaging unit 20, on the outer side of the reflective imaging unit 20 (i.e.,...) Figure 1 The second image P2 is formed as a virtual image on the left side of the central reflection imaging unit 20.

[0042] Thus, the optical system composed of optical elements in the first optical path can provide VPA functionality to display a real image that provides virtual images or information, and the optical system composed of optical elements in the second optical path can provide HUD functionality to display a virtual image that provides navigation or augmented reality fusion. Thus, the display device 10 has both HUD and VPA functionality. Moreover, since the HUD and VPA functions are implemented by sharing the imaging unit 130, the display device 10 can be manufactured in a smaller size. This allows the display device 10 to be arranged within the IP, thereby saving interior space and thus improving the flexibility of the interior layout.

[0043] It is conceivable that the object distance corresponding to the first optical path can be further adjusted to be less than twice the equivalent focal length corresponding to the first optical path.

[0044] In this way, the object distance corresponding to the first optical path is between one and two times the equivalent focal length. In this case, the first image P1 is a magnified real image. As a result, the displayed screen of this real image is larger, making it easier for drivers and passengers to clearly identify the content displayed in the first image P1, which is conducive to better human-computer interaction.

[0045] It is also conceivable that the object distance corresponding to the first optical path can be adjusted to be equal to twice the equivalent focal length corresponding to the first optical path, thereby making the first image P1 a real image of the same size. Moreover, it is also conceivable that the object distance corresponding to the first optical path can be adjusted to be greater than twice the equivalent focal length corresponding to the first optical path, thereby making the first image P1 a reduced real image.

[0046] In some implementations, such as Figure 1 As shown, the imaging unit 130 may include a first reflection unit 131 and a second reflection unit 132. Both the first reflection unit 131 and the second reflection unit 132 are disposed in the first optical path. The first image light S1 first propagates to the second reflection unit 132, and then is reflected by the second reflection unit 132 and propagates to the first reflection unit 131.

[0047] In other words, the first image light S1 can be reflected between the first reflection unit 131 and the second reflection unit 132 arranged on the first optical path, thereby realizing the folding of the first optical path between the first reflection unit 131 and the second reflection unit 132.

[0048] In this way, the size of the display device 10 can be reduced while ensuring that the object distance corresponding to the first optical path is greater than the equivalent focal length corresponding to the first optical path, which helps to install the display device 10 within the IP.

[0049] For example, such as Figure 1As shown, the first reflecting unit 131 can be a concave reflecting mirror, and the second reflecting unit 132 can be a plane reflecting mirror. However, the first reflecting unit 131 and the second reflecting unit 132 can also take other forms, which are not limited here.

[0050] Furthermore, it is conceivable that the imaging unit 130 is a single concave mirror, or it can take any other suitable form.

[0051] In some implementations, such as Figure 2 As shown, the first reflection unit 131 is movable so that the principal optical axes of the first image ray S1 and the second image ray S2 emitted from the first reflection unit 131 coincide.

[0052] For example, the first reflecting unit 131 can be rotated by a motor to reflect a first image ray S1 at a first position L1 and a second image ray S2 at a second position L2. Furthermore, the principal optical axis of the first image ray S1 emitted from the first reflecting unit 131 at the first position L1 coincides with the principal optical axis of the second image ray S2 emitted from the first reflecting unit 131 at the second position L2. Other modes of movement of the first reflecting unit 131 are also conceivable and are not limited here.

[0053] By aligning the principal optical axes of the first image ray S1 emitted from the first reflection unit 131 and the second image ray S2, the first image ray S1 and the second image ray S2 reflected by the reflection imaging unit 20 are on the same propagation path. In this way, the center of the first image P1, the center of the second image P2, and the center of the eye box 30 are on the same axis (i.e., the first image P1 and the second image P2 are coaxially arranged), so that the first image P1 and the second image P2 are on the same focusing plane. Therefore, when the driver and passengers observe the first image P1 inside the cabin and the second image P2 outside the cabin, they only need to switch the image display without adjusting their line of sight, thereby improving the consistency of the visual experience.

[0054] like Figure 2 As shown, in the above embodiment, it is conceivable that the second reflection unit 132 may not be provided in the second optical path.

[0055] In this configuration, the first image ray S1 is reflected only once by the second reflection unit 132, while the second image ray S2 does not pass through the second reflection unit 132. This reduces the light efficiency loss of the first image ray S1 and the second image ray S2, thereby increasing the display brightness of the first image P1 and the second image P2 and reducing power consumption.

[0056] It is conceivable that, with reference to Figure 3The first reflecting unit 131 and the second reflecting unit 132 can both be disposed in the second optical path, and the second reflecting unit 132 is a beam splitter.

[0057] A beam splitter is a beam-splitting element that transmits and reflects incident light in a specific ratio. For example, a beam splitter can be a flat plate lens with a certain splitting ratio and no polarizing characteristics, such as a semi-transparent and semi-reflective mirror; or, a beam splitter can be a flat plate lens with a specific splitting ratio and polarizing characteristics, such as a polarizing beam splitter that reflects vertically polarized light and transmits horizontally polarized light.

[0058] By making the second reflecting unit 132 a beam splitter, and placing both the first reflecting unit 131 and the second reflecting unit 132 in the second optical path, the beam splitter will simultaneously be located in the first and second optical paths. In this way, the second reflecting unit 132 can reflect the first image light ray S1 to achieve folding of the first optical path; at the same time, it will not block the first image light ray S1 and the second image light ray S2, but will allow the first image light ray S1 and the second image light ray S2 to pass through.

[0059] Therefore, the display device 10 can be designed to be more compact, thereby reducing the size of the display device 10 and facilitating its installation within the IP.

[0060] It is conceivable that, for example Figure 3 As shown, in the second optical path, the first reflective unit 131 is located between the second display unit 120 and the second reflective unit 132.

[0061] In this configuration, in the first optical path, the first image ray S1 first propagates to the second reflection unit 132, is reflected by the second reflection unit 132, propagates to the first reflection unit 131, is reflected again by the first reflection unit 131, propagates back to the second reflection unit 132, and then is transmitted through the second reflection unit 132 to the reflective imaging unit 20, thereby forming the first image P1. In the second optical path, the second image ray S2 first propagates to the first reflection unit 131, is reflected by the first reflection unit 131, propagates to the second reflection unit 132, and then is transmitted through the second reflection unit 132 to the reflective imaging unit 20, thereby forming the second image P2.

[0062] For example, the object distance corresponding to the first optical path is 410mm, and the equivalent focal length corresponding to the first optical path is 239mm. This object distance is greater than one time the equivalent focal length but less than two times the equivalent focal length, and the first image P1 is a magnified real image. The object distance corresponding to the second optical path is 146mm, and the equivalent focal length corresponding to the second optical path is 239mm. This object distance is less than one time the equivalent focal length, and the second image P2 is a magnified virtual image.

[0063] In this way, the angle of incidence of the first image ray S1, reflected by the second reflection unit 132, onto the first reflection unit 131 can be relatively small. Therefore, the aberrations of the optical system in this embodiment can be more easily compensated by optimizing the surface shape of the first reflection unit 131, thereby optimizing optical performance parameters, such as parameters characterizing image sharpness (modulation transfer function (MTF)) and parameters characterizing image distortion (distortion).

[0064] It is conceivable that, in Figure 3 In the case of the embodiment shown, refer to Figure 4 The first image ray S1 can be either vertically polarized light or horizontally polarized light, and the second image ray S2 can be either vertically polarized light or horizontally polarized light. The second reflecting unit (beam splitter) 132 includes a phase retardation plate 1321 and a polarizing beam splitter body 1322. The phase retardation plate 1321 is located between the first display unit 110 and the polarizing beam splitter body 1322 in the first optical path and can generate a phase difference of π / 2 odd multiple. The polarizing beam splitter body 1322 reflects either vertically polarized light or horizontally polarized light and transmits the other vertically polarized light or horizontally polarized light.

[0065] Phase retarder 1321 enables the conversion between linearly polarized and circularly polarized light by generating a phase difference that is an odd multiple of π / 2. Phase retarder 1321 can be, for example, a quarter-wave plate or any other suitable type of phase retarder.

[0066] For example, such as Figure 4 As shown, the first image ray S1 is vertically polarized light, and the second image ray S2 is horizontally polarized light. In this case, in the first optical path, when the first image ray S1 propagates from the first display unit 110 to the phase retardation plate 1321, the phase of the first image ray S1 is delayed by π / 2 by the phase retardation plate 1321, causing the vertically polarized light to be converted into right-hand circularly polarized light. Next, the first image ray S1 transmitted from the phase retardation plate 1321 propagates to the polarizing beam splitter body 1322, and after reflection by the polarizing beam splitter body 1322, it propagates back to the phase retardation plate 1321. At this time, the phase of the first image ray S1 is again delayed by π / 2 by the phase retardation plate 1321, causing the right-hand circularly polarized light to be converted into horizontally polarized light. The first image ray S1 transmitted from the phase retardation plate 1321 is then reflected by the first reflecting unit 131 and re-enters the phase retardation plate 1321, and its phase is again delayed by π / 2 by the phase retardation plate 1321, causing the horizontally polarized light to be converted into left-hand circularly polarized light. Finally, the first image light S1 transmitted from the phase retardation plate 1321 propagates through the polarizing beam splitter body 1322 to the reflection imaging unit 20, thereby forming the first image P1.

[0067] In the second optical path, the second image light S2 propagates to the first reflecting unit 131, and after being reflected by the first reflecting unit 131, it is incident on the phase retardation plate 1321. The phase is delayed by π / 2 by the phase retardation plate 1321, so that the horizontally polarized light is converted into left-handedly polarized light. Then, the second image light S2 transmitted from the phase retardation plate 1321 propagates through the polarizing beam splitter body 1322 to the reflective imaging unit 20, thereby forming the second image P2.

[0068] In this way, the light efficiency loss of the first image ray S1 and the second image ray S2 can be reduced, thereby improving the display brightness of the image and reducing power consumption.

[0069] In some implementations, refer to Figure 5 In the second optical path, the second reflective unit 132 can be located between the second display unit 120 and the first reflective unit 131.

[0070] In this configuration, in the first optical path, the first image ray S1 first propagates to the second reflection unit 132, is reflected by the second reflection unit 132, propagates to the first reflection unit 131, is reflected by the first reflection unit 131, and then propagates to the reflective imaging unit 20, thereby forming the first image P1. In the second optical path, the second image ray S2 first propagates to the second reflection unit 132, is transmitted through the second reflection unit 132, propagates to the first reflection unit 131, is reflected by the first reflection unit 131, and then propagates to the reflective imaging unit 20, thereby forming the second image P2.

[0071] In this way, in the second optical path, the second image light S2 reflected by the first reflection unit 131 is directly projected onto the reflective imaging unit 20 without being transmitted through the second reflection unit 132 again, thereby improving the light efficiency, thereby increasing the display brightness of the second image P2 and reducing power consumption.

[0072] Furthermore, it is conceivable that, in this embodiment, the principal optical axes of the first image ray S1 and the second image ray S2 emitted from the second reflection unit 132 can be made coaxial.

[0073] Therefore, without moving the first reflection unit 131, the first image P1 and the second image P2, which are coaxially set, can be displayed simultaneously.

[0074] It is conceivable that, in the above embodiment, the first image ray S1 can be one of vertically polarized light and horizontally polarized light, the second image ray S2 can be the other of vertically polarized light and horizontally polarized light, and the second reflecting unit 132 is a polarizing beam splitter, which reflects one of the vertically polarized light and horizontally polarized light and transmits the other of the vertically polarized light and horizontally polarized light.

[0075] For example, still as Figure 5 As shown, the first image ray S1 is vertically polarized light, and the second image ray S2 is horizontally polarized light. In this case, in the first optical path, the first image ray S1 propagates to the second reflection unit 132, is reflected by the second reflection unit 132, propagates to the first reflection unit 131, and is then reflected by the first reflection unit 131 before directly propagating to the reflective imaging unit 20, thereby forming the first image P1.

[0076] In the second optical path, the second image light S2 propagates to the second reflection unit 132, is transmitted through the second reflection unit 132, propagates to the first reflection unit 131, and is then reflected by the first reflection unit 131 and directly propagates to the reflection imaging unit 20, thereby forming the second image P2.

[0077] In this way, the light efficiency loss of the first image ray S1 and the second image ray S2 can be reduced, thereby improving the display brightness of the image and reducing power consumption.

[0078] It is conceivable that, for example Figure 5 As shown, the display device 10 may further include at least one reflector 140, which is located in the first optical path between the first display unit 110 and the second reflector 132.

[0079] In this way, the first optical path can be further folded, thereby further reducing the size of the display device 10.

[0080] In some implementations, refer to Figure 6 In the second optical path, only the second reflection unit 132 of the first reflection unit 131 and the second reflection unit 132 is disposed so that the second image light S2 is reflected by the second reflection unit 132 through the first surface 132a and propagated to the first surface 132a. The first surface 132a is opposite to the second surface 132b of the second reflection unit 132 that reflects the first image light S1.

[0081] For example, such as Figure 6 As shown, the second reflecting unit 132 can be a mirror with a reflective film on both the first surface 132a and the second surface 132b. In the first optical path, the first image light ray S1 first propagates to the second reflecting unit 132, is reflected by the second surface 132b of the second reflecting unit 132, and then propagates to the first reflecting unit 131. After being reflected by the first reflecting unit 131, it propagates to the reflective imaging unit 20, thereby forming the first image P1. In the second optical path, the second image light ray S2 first propagates to the second reflecting unit 132, is reflected by the first surface 132a of the second reflecting unit 132, and then propagates to the reflective imaging unit 20, thereby forming the second image P2.

[0082] In this way, the first image P1 and the second image P2 can also be displayed simultaneously. Moreover, the second image P2 formed by the display device 10 of this embodiment is closer to the reflective imaging unit 20 on the outside of the reflective imaging unit 20, and has a larger downward viewing angle, so it is particularly suitable for panoramic head-up display (PHUD) scenarios.

[0083] It is conceivable that, with reference to Figure 7 The second reflecting unit 132 can be a beam splitter.

[0084] For example, such as Figure 7 As shown, in the first optical path, the first image light S1 first propagates to the second reflection unit 132, is reflected by the second reflection unit 132 and then propagates to the first reflection unit 131, is reflected by the first reflection unit 131 and then propagates to the second reflection unit 132, and then is transmitted from the second reflection unit 132 and propagates to the reflection imaging unit 20, thereby forming the first image P1.

[0085] In the second optical path, the second image light S2 first propagates to the second reflection unit 132, and after being reflected by the second reflection unit 132, it propagates to the reflection imaging unit 20, thereby forming the second image P2.

[0086] In this way, the second reflection unit 132 can reflect the first image light ray S1 to achieve the folding of the first optical path, while not blocking the first image light ray S1, but allowing the first image light ray S1 to pass through. As a result, the display device 10 can be designed to be more compact, thereby reducing the size of the display device 10 and facilitating its installation within the IP.

[0087] It is conceivable that, in Figure 7 In the case of the embodiment shown, refer to Figure 8 The first image ray S1 can be either vertically polarized light or horizontally polarized light, and the second image ray S2 can also be either vertically polarized light or horizontally polarized light, that is, the polarization states of the first image ray S1 and the second image ray S2 are the same; the second reflection unit 132 includes a phase retardation plate 1321 and a polarizing beam splitter body 1322. The phase retardation plate 1321 is located between the first display unit 110 and the polarizing beam splitter body 1322 in the first optical path and can generate a phase difference of π / 2 odd multiple. The polarizing beam splitter body 1322 reflects one of the vertically polarized light and horizontally polarized light and transmits the other of the vertically polarized light and horizontally polarized light.

[0088] For example, such as Figure 8As shown, both the first image ray S1 and the second image ray S2 are vertically polarized light. In this case, in the first optical path, when the first image ray S1 propagates from the first display unit 110 to the phase retardation plate 1321, the phase of the first image ray S1 is delayed by π / 2 by the phase retardation plate 1321, causing the vertically polarized light to be converted into right-hand circularly polarized light. Next, the first image ray S1 transmitted from the phase retardation plate 1321 propagates to the polarizing beam splitter body 1322, and after reflection by the polarizing beam splitter body 1322, propagates back to the phase retardation plate 1321. At this time, the phase of the first image ray S1 is again delayed by π / 2 by the phase retardation plate 1321, causing the right-hand circularly polarized light to be converted into horizontally polarized light. The first image ray S1 transmitted from the phase retardation plate 1321 is then reflected by the first reflecting unit 131 and incident on the phase retardation plate 1321, where its phase is again delayed by π / 2 by the phase retardation plate 1321, causing the horizontally polarized light to be converted into left-hand circularly polarized light. Finally, the first image light S1 transmitted from the phase retardation plate 1321 propagates through the polarizing beam splitter body 1322 to the reflection imaging unit 20, thereby forming the first image P1.

[0089] In the second optical path, the second image light S2 first propagates to the second reflection unit 132, and after being reflected by the second reflection unit 132, it propagates to the reflection imaging unit 20, thereby forming the second image P2.

[0090] In this way, the light efficiency loss of the first image ray S1 and the second image ray S2 can be reduced, thereby improving the display brightness of the image and reducing power consumption.

[0091] Considering that the second image P2 formed by the display device 10 in the above embodiment has a large downward viewing angle, it is particularly suitable for PHUD scenarios. It is conceivable that, referring to... Figure 9 The display device 10 may also include a synthesis mirror 150, and the imaging unit 130 projects the second image light S2 onto the synthesis mirror 150 to form a second image P2.

[0092] In this case, a second image P2 with a larger downward angle of view can be formed by a specially designed synthesizing mirror 150. Moreover, since the first image P1 with a smaller downward angle of view can usually be formed by the windshield, it is possible to separate the images and use the windshield to eliminate the ghosting of the first optical path, and use the synthesizing mirror 150 to eliminate the ghosting of the second optical path.

[0093] For example, ghosting in the first optical path can be eliminated by setting the angle of the polyvinyl butyral (PVB) in the windshield; while ghosting in the second optical path can be eliminated by making the synthesizing lens 150 into a lens with a set wedge angle, or by blackening the side of the synthesizing lens 150 away from the eye box, and so on.

[0094] In this way, compared to the case where both the first image P1 and the second image P2 are formed through the windshield, the ghosting of the first and second optical paths can be eliminated more effectively.

[0095] According to another aspect of this disclosure, referring to Figure 10 An optical system 1 is also provided.

[0096] The optical system 1 includes a display device 10 and a reflective imaging unit 20.

[0097] The reflective imaging unit 20 is located on the light-emitting side of the display device 10 to receive and reflect light emitted from the display device 10.

[0098] As discussed earlier, it is conceivable that the reflective imaging unit 20 could be a windshield or a composite mirror of a vehicle.

[0099] Furthermore, it is conceivable that, in the absence of the composite mirror 150 in the display device 10, the reflective imaging unit 20 may include the windshield 210 and the composite mirror 220 of a vehicle, wherein the imaging unit 130 projects a first image light S1 onto one of the windshield 210 and the composite mirror 220, and projects a second image light S2 onto the other of the windshield 210 and the composite mirror 220.

[0100] For example, refer to Figure 11 Similar to the previously discussed implementation, for an implementation particularly suitable for PHUD scenarios, the imaging unit 130 can project a first image ray S1 onto the windshield 210 and a second image ray S2 onto the composite mirror 220.

[0101] In this disclosure, the terms "first," "second," etc., are used merely for descriptive purposes and should not be considered restrictive. Furthermore, although this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the specific embodiments described and shown herein. Various changes to the exemplary embodiments can be made by those skilled in the art without departing from the scope defined by the claims of this disclosure.

[0102] The features mentioned and / or shown in the foregoing description of exemplary embodiments of this disclosure may be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. Such combinations or substitutions should also be considered as including within the scope of protection of this disclosure.

Claims

1. A display device, characterized in that, include: The first display unit is disposed in the first optical path and emits the first image light beam; The second display unit is disposed in the second optical path and emits a second image light beam; as well as An imaging unit is disposed in the first optical path and the second optical path. The imaging unit receives and reflects the first image light to form a first image from the first image light, and receives and reflects the second image light to form a second image from the second image light. In this configuration, the imaging unit, without requiring switching, is based on a preset optical layout, where the object distance corresponding to the first optical path is greater than the equivalent focal length corresponding to the first optical path to form a real image, and the object distance corresponding to the second optical path is less than the equivalent focal length corresponding to the second optical path to form a virtual image. The imaging unit includes a first reflection unit and a second reflection unit, both of which are disposed in the first optical path. The first image light first propagates to the second reflection unit, and then is reflected by the second reflection unit before propagating back to the first reflection unit. Both the first reflecting unit and the second reflecting unit are disposed in the second optical path, and the second reflecting unit is a beam splitter.

2. The display device according to claim 1, characterized in that, The object distance corresponding to the first optical path is less than twice the equivalent focal length corresponding to the first optical path.

3. The display device according to claim 1, characterized in that, In the second optical path, the first reflective unit is located between the second display unit and the second reflective unit.

4. The display device according to claim 3, characterized in that, The first image light is one of vertically polarized light and horizontally polarized light, and the second image light is the other of vertically polarized light and horizontally polarized light. The second reflection unit includes a phase retardation plate and a polarizing beam splitter body. The phase retardation plate is located between the first display unit and the polarizing beam splitter body in the first optical path and can generate a phase difference of π / 2 odd multiple. The polarizing beam splitter body reflects one of the light rays and transmits the other light rays.

5. The display device according to claim 1, characterized in that, In the second optical path, the second reflective unit is located between the second display unit and the first reflective unit.

6. The display device according to claim 5, characterized in that, The first image ray is one of vertically polarized light and horizontally polarized light, the second image ray is the other of vertically polarized light and horizontally polarized light, and the second reflecting unit is a polarizing beam splitter, which reflects one of the polarizing rays and transmits the other.

7. An optical system, characterized in that, include: The display device according to any one of claims 1 to 6; as well as A reflective imaging unit is located on the light-emitting side of the display device to receive and reflect light emitted from the display device.

Images