Display device and vehicle

Abstract

According to the display device and the vehicle, a phase modulation element is arranged on the light emitting side of an image source, a light splitting element is arranged on the light emitting side of the phase modulation element, and the phase modulation element converts first polarized light emitted by the image source into second polarized light to be emitted in the first stage and transmits the first polarized light in the second stage; the light splitting element reflects one of the first polarized light and the second polarized light emitted by the phase modulation element and transmits the other one, so that through the cooperation of the phase modulation element and the light splitting element, the emergent light of the image source can be transmitted to the projection imaging medium through different light paths to generate a bifocal plane image; and the image source does not need to be partitioned, so that the resolution ratio of the generated front and back image planes positioned on different focal planes is not reduced, and the problem that the resolution ratio is reduced in the existing multi-focal-plane AR-HUD display scheme adopting the single PGU and the double optical paths is solved.

Description

Technical Field

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

[0002] With the development of display technologies, in-vehicle augmented reality head-up display (AR-HUD) technologies have also entered a period of rapid development. By projecting driving information images of 3 to 5 inches onto a position 2.5 to 10 meters in front of the driver, this technology forms virtual images of 30 to 70 inches and integrates them with the real road environment. The characteristic that the image plane is approximately perpendicular to the driver's line of sight significantly reduces the frequency of the driver's line-of-sight transfer, effectively improving driving safety. In addition, AR-HUD technologies can also provide the driver with an entertaining and technological experience, enhancing driving comfort and the human-machine interaction experience. This makes the current AR-HUD system not only need to carry basic information such as vehicle speed and battery power, but also need to integrate diversified information such as assisted driving, navigation route guidance, entertainment, and dining. Placing such a large amount of information on a single projection plane and presenting it all in front of the driver is, on the one hand, not conducive to distinguishing effective information, and on the other hand, it will affect the driver's line of sight and driving safety.

[0003] Therefore, developing a multi-focal-plane projection solution is the future development trend. Currently, there are mainly two technical routes for multi-focal-plane AR-HUD displays: one is to adopt a dual-picture generation unit (PGU) with a dual-optical path solution. The resolutions of the front and rear image planes located at different focal planes generated are relatively high, but the volume of the dual-PGU optical machine is large and it is difficult to mass-produce; the other is to adopt a single-PGU dual-optical path solution, which requires the PGU to be divided vertically, and a baffle needs to be added in the middle, which will cause the resolutions of the front and rear image planes located at different focal planes to decrease. This requires a high-resolution PGU, which will further lead to a decrease in the transmittance of the PGU and an increase in cost. Therefore, the existing multi-focal-plane AR-HUD display solution using a single-PGU dual-optical path has a problem of resolution degradation that urgently needs to be solved. Summary of the Invention

[0004] The present application provides a display device and a vehicle to alleviate the technical problem of resolution degradation existing in the existing multi-focal-plane AR-HUD display solution using a single-PGU dual-optical path.

[0005] To solve the above problems, the technical solutions provided by the present application are as follows:

[0006] An embodiment of the present application provides a display device, which includes:

[0007] An image source configured to emit first polarized light;

[0008] A phase modulation element, located on the light-emitting side of the image source, is configured to convert the first polarized light into the second polarized light and emit it in a first stage, and transmit the first polarized light in a second stage, wherein the polarization direction of the first polarized light is different from that of the second polarized light;

[0009] A beam splitting element, located on the light-emitting side of the phase modulation element, is configured to reflect one of the first polarized light and the second polarized light emitted by the phase modulation element and transmit the other;

[0010] A reflection element is configured to reflect the reflected light of the beam splitting element and / or the transmitted light of the beam splitting element to a projection imaging medium to generate an image.

[0011] In the display device provided by the embodiment of the present application, one of the first polarized light and the second polarized light is S polarized light, and the other is P polarized light.

[0012] In the display device provided by the embodiment of the present application, when the first polarized light is S polarized light and the second polarized light is P polarized light, the beam splitting element is configured to reflect the first polarized light and transmit the second polarized light.

[0013] In the display device provided by the embodiment of the present application, the beam splitting element includes a reflective polarizing film.

[0014] In the display device provided by the embodiment of the present application, the display device further includes a first dimming element located on the light-emitting side of the beam splitting element, and the first dimming element is configured to convert the second polarized light transmitted by the beam splitting element into the first polarized light.

[0015] In the display device provided by the embodiment of the present application, the first dimming element includes a half-wave plate.

[0016] In the display device provided by the embodiment of the present application, a second dimming element is provided between the inner layer and the outer layer of the projection imaging medium, and the outer layer is located on the side of the inner layer away from the image source;

[0017] Wherein, the second dimming element is configured to convert the P polarized light incident on the projection imaging medium and transmitted through the inner layer of the projection imaging medium into S polarized light, and convert the S polarized light reflected by the outer layer of the projection imaging medium into P polarized light to be transmitted through the inner layer of the projection imaging medium.

[0018] In the display device provided by the embodiment of the present application, the second dimming element includes a half-wave plate.

[0019] In the display device provided in the embodiment of the present application, the reflection element includes a first reflector and a second reflector. The first reflector is configured to reflect the transmitted light of the beam splitting element to the projection imaging medium to display the near focal plane image. The second reflector is configured to reflect the reflected light of the beam splitting element to the first reflector. The first reflector is further configured to reflect the reflected light of the second reflector to the projection imaging medium to display the far focal plane image. The far focal plane image is located on a side of the near focal plane image away from the projection imaging medium.

[0020] In the display device provided in the embodiment of the present application, the first reflector includes a concave free-form surface reflector, and the second reflector includes one of a plane mirror, a convex free-form surface reflector, and a concave free-form surface reflector.

[0021] In the display device provided in the embodiment of the present application, within a period when the image source displays an image, it includes at least one first sub-period and at least one second sub-period that alternate. Both the first sub-period and the second sub-period include at least one frame of image.

[0022] The first sub-period corresponds to the first stage, and the second sub-period corresponds to the second stage.

[0023] In the display device provided in the embodiment of the present application, the phase modulation element includes one of a liquid crystal phase modulator, a piezoelectric phase modulator, and a thermo-optical phase modulator.

[0024] In the display device provided in the embodiment of the present application, the phase modulation element is the liquid crystal phase modulator. The phase modulation element includes a first electrode, a second electrode, and a liquid crystal layer located between the first electrode and the second electrode.

[0025] When the phase modulation element is in the first stage, the liquid crystal molecules of the liquid crystal layer have a first arrangement state. When the phase modulation element is in the second stage, the liquid crystal molecules of the liquid crystal layer have a second arrangement state, and the second arrangement state is different from the first arrangement state.

[0026] The embodiment of the present application further provides a vehicle, which includes a projection imaging medium and the display device according to any one of the foregoing embodiments.

[0027] The beneficial effects of the present application are as follows: In the display device and the vehicle provided by the present application, a phase modulation element is provided on the light-emitting side of the image source, and a beam splitting element is provided on the light-emitting side of the phase modulation element. The phase modulation element converts the first polarized light emitted by the image source into the second polarized light and emits it in the first stage, and transmits the first polarized light in the second stage. The beam splitting element reflects one of the first polarized light and the second polarized light emitted by the phase modulation element and transmits the other. In this way, through the cooperation of the phase modulation element and the beam splitting element, the light emitted by the image source can be transmitted to the projection imaging medium through different light paths to generate a bifocal plane image, and there is no need to partition the image source, so that the resolution of the front and rear image planes located at different focal planes will not decrease, alleviating the problem of resolution decrease in the existing multi-focal plane AR-HUD display scheme using a single PGU double light path. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0029] Figure 1 It is a schematic structural diagram of a display device provided by an embodiment of the present application.

[0030] Figure 2 It is Figure 1 a schematic diagram of the principle of time-division multiplexing of the phase modulation element in

[0031] Figure 3 It is Figure 1 a schematic diagram of a detailed structure of the phase modulation element in

[0032] Figure 4 It is another schematic structural diagram of a display device provided by an embodiment of the present application.

[0033] Figure 5 It is yet another schematic structural diagram of a display device provided by an embodiment of the present application.

[0034] Figure 6 It is still another schematic structural diagram of a display device provided by an embodiment of the present application.

[0035] Figure 7 It is Figure 6 a schematic diagram of a partial detailed structure of the projection imaging medium in

[0036] Figure 8 It is a partial schematic diagram of a vehicle provided by an embodiment of the present application.

[0037] Reference numerals:

[0038] 1000, vehicle;

[0039] 100, display device;

[0040] 10, image source; 11, first polarized light; 12, second polarized light;

[0041] 20, phase modulation element; 21, first electrode; 22, second electrode; 23, liquid crystal layer; 24, first substrate; 25, second substrate;

[0042] 30, beam splitter element;

[0043] 40, reflection element; 41, first mirror; 42, second mirror;

[0044] 50, first dimming element;

[0045] 60, second dimming element;

[0046] 200, projection imaging medium; 201, inner layer; 202, outer layer; 203, interlayer;

[0047] 301, near - focal plane image; 302, far - focal plane image;

[0048] 400, eye;

[0049] T, a time period; T1, first sub - time period; T2, second sub - time period. Detailed implementation manners

[0050] The description of the following embodiments refers to the attached drawings, which are used to illustrate specific embodiments in which the present application can be implemented. The directional terms mentioned in the present application, such as [up], [down], [front], [back], [left], [right], [inside], [outside], [side], etc., are only references to the directions in the attached drawings. Therefore, the directional terms used are for explaining and understanding the present application, rather than for limiting the present application. In the drawings, units with similar structures are denoted by the same reference numerals. In the drawings, for clear understanding and easy description, the thicknesses of some layers and regions are exaggerated. That is, the dimensions and thicknesses of each component shown in the drawings are arbitrarily shown, but the present application is not limited thereto.

[0051] Please refer to Figures 1 to 3 , Figure 1 , which is a schematic structural diagram of a display device 100 provided by an embodiment of the present application, Figure 2 is Figure 1 a schematic diagram of the principle of time - division multiplexing of the phase modulation element 20 in Figure 3 is Figure 1 a schematic diagram of a detailed structure of the phase modulation element 20 in Figure 1, the display device 100 includes an image source 10, a phase modulation element 20 located on the light-emitting side of the image source 10, and a beam splitting element 30 located on the light-emitting side of the phase modulation element 20. The image source 10 is configured to emit first polarized light 11. The phase modulation element 20 is configured to convert the first polarized light 11 into second polarized light 12 and emit it in the first stage, and transmit the first polarized light 11 in the second stage. The polarization direction of the first polarized light 11 is different from that of the second polarized light 12. The beam splitting element 30 is configured to reflect one of the first polarized light 11 and the second polarized light 12 emitted by the phase modulation element 20 and transmit the other. The display device 100 further includes a reflection element 40 configured to reflect the reflected light of the beam splitting element 30 and / or the transmitted light of the beam splitting element 30 to a projection imaging medium 200 to generate an image. When the display device 100 is applied to in-vehicle display, the projection imaging medium 200 is the front windshield of the vehicle.

[0052] In this embodiment, through the cooperation of the phase modulation element 20 and the beam splitting element 30, the light emitted by the image source 10 can be transmitted to the projection imaging medium 200 through different optical paths to generate a bifocal image, and there is no need to partition the image source 10, so that the resolution of the front and rear image planes located at different focal planes generated will not decrease, alleviating the problem of resolution decrease in the existing multi-focal plane AR-HUD display scheme using a single PGU double optical path.

[0053] Specifically, the image source 10 includes an image generation unit (picture generation unit, PGU), and the image generation unit can output image light carrying image data, and this image light has a specific polarization direction. Thus, the image source 10 can emit first polarized light 11 with a specific polarization direction. For example, the first polarized light 11 is S-polarized light or P-polarized light. Optionally, the image generation unit can be a liquid crystal on silicon (LCOS) display, an organic light-emitting diode (OLED) display, a liquid crystal display (LCD) display, etc.

[0054] Continue to refer to Figure 1, the phase modulation element 20 is disposed on the light-emitting side of the image source 10. The phase modulation element 20 is configured to convert the first polarized light 11 emitted from the image source 10 into a second polarized light 12 in a first stage. The polarization direction of the second polarized light 12 is different from that of the first polarized light 11. For example, the polarization direction of the second polarized light 12 is perpendicular to that of the first polarized light 11. One of the first polarized light 11 and the second polarized light 12 is S-polarized light, and the other is P-polarized light.

[0055] The phase modulation element 20 is further configured to not change the polarization direction of the first polarized light 11 emitted from the image source 10 in a second stage, and enable the first polarized light 11 emitted from the image source 10 to directly transmit through the phase modulation element 20. The second stage and the first stage may be a certain sub-period within a period T when the image source 10 displays an image.

[0056] Specifically, referring to Figure 2 , within a period T when the image source 10 displays an image, it includes at least one first sub-period T1 and at least one second sub-period T2 in alternation. For example, the period T is 1 second, and each period T includes two first sub-periods T1 and two second sub-periods T2. However, the present application is not limited thereto. The period T of the present application may also be less than 1 second, and each period T may further include more or fewer alternating first sub-periods T1 and second sub-periods T2. Both the first sub-period T1 and the second sub-period T2 include at least one frame of picture. In the first sub-period T1, the first polarized light 11 emitted from the image source 10 carries first image data; in the second sub-period T2, the first polarized light 11 emitted from the image source 10 carries second image data.

[0057] Among them, the first sub-period T1 corresponds to the first stage, and the second sub-period T2 corresponds to the second stage. That is, within the first sub-period T1 when the image source 10 displays an image, the phase modulation element 20 changes the polarization direction of the first polarized light 11 carrying the first image data emitted from the image source 10, so that the first polarized light 11 carrying the first image data emitted from the image source 10 is converted into a second polarized light 12 carrying the first image data, and the second polarized light 12 carrying the first image data is emitted from the phase modulation element 20; within the second sub-period T2 when the image source 10 displays an image, the phase modulation element 20 does not change the polarization direction of the first polarized light 11 carrying the second image data emitted from the image source 10, and enables the first polarized light 11 carrying the second image data emitted from the image source 10 to directly transmit through the phase modulation element 20.

[0058] Optionally, the phase modulation element 20 includes one of phase modulators such as a liquid crystal phase modulator, a piezoelectric phase modulator, and a thermo-optic phase modulator. Among them, the liquid crystal phase modulator utilizes the electro-optic birefringence effect of liquid crystals. When a voltage is applied, the alignment direction of liquid crystal molecules changes, resulting in a change in its refractive index. This change in refractive index affects the phase delay amount of the light passing through the liquid crystal layer 23. By adjusting the applied voltage, the phase delay amount can be continuously changed, thereby achieving a change in the polarization direction of polarized light. The piezoelectric phase modulator utilizes the inverse piezoelectric effect of piezoelectric ceramics. By externally applying pressure or voltage, the piezoelectric ceramics generate deformation, thereby stretching or compressing the optical fiber wound thereon, changing the length and refractive index of the optical fiber, and further adjusting the phase delay amount of the light passing through the optical fiber, thereby achieving a change in the polarization direction of polarized light. The thermo-optic phase modulator is based on the thermo-optic effect, that is, the refractive index of a material changes with temperature. By heating the thermosensitive material with a heating element to change its temperature, a change in refractive index is caused, thereby achieving phase modulation of the optical signal. Common types of thermo-optic phase modulators include silicon-based and glass-based thermo-optic phase modulators. The silicon-based thermo-optic phase modulator is compatible with silicon-based integrated circuit processes and is easy to integrate large-scale arrays. The glass-based thermo-optic phase modulator has good optical performance and stability.

[0059] In some embodiments, referring to Figure 3 , taking the phase modulation element 20 as a liquid crystal phase regulator as an example, the phase modulation element includes a first electrode 21, a second electrode 22, and a liquid crystal layer 23 located between the first electrode 21 and the second electrode 22. Optionally, the phase modulation element 20 further includes a first substrate 24 and a second substrate 25 disposed opposite to each other. The first electrode 21 is disposed on the surface of the first substrate 24, and the second electrode 22 is disposed on the surface of the second substrate 25. For example, the first electrode 21 is disposed on the surface of the first substrate 24 facing the second substrate 25, and the second electrode 22 is disposed on the surface of the second substrate 25 facing the first substrate 24. Both the first substrate 24 and the second substrate 25 can be glass substrates, etc. It should be noted that the structure of the liquid crystal phase regulator in this application is not limited to this. For example, in some other embodiments, the first electrode 21 and the second electrode 22 of the liquid crystal phase regulator can be located on the same side of the liquid crystal layer 23.

[0060] By applying a voltage across the first electrode 21 and the second electrode 22, an electric field can be formed between the first electrode 21 and the second electrode 22, and the arrangement state of the liquid crystal molecules in the liquid crystal layer 23 will change under the action of the electric field force. For example, when the phase modulation element is in the first stage, the liquid crystal molecules in the liquid crystal layer 23 have a first arrangement state; when the phase modulation element is in the second stage, the liquid crystal molecules in the liquid crystal layer 23 have a second arrangement state, and the second arrangement state is different from the first arrangement state. The change in the arrangement state of the liquid crystal molecules will cause a change in the refractive index of the liquid crystal molecules, and this change in refractive index will affect the phase delay amount of the light passing through the liquid crystal layer 23. Since the liquid crystal phase modulator can change the phase delay amount of light, when the incident light is linearly polarized light, the change in the phase delay amount will cause the polarization direction of the outgoing light to rotate. For example, when the polarization direction makes a 45-degree angle with the fast axis or the slow axis of the liquid crystal layer 23, applying an appropriate voltage can rotate the polarization direction of the light by 90 degrees, thereby converting the S-polarized light into P-polarized light, and vice versa.

[0061] Continue to refer to Figure 1 , the beam splitting element 30 is disposed on the light output side of the phase modulation element 20, and the beam splitting element 30 is configured to separate the first polarized light 11 and the second polarized light 12 output from the phase modulation element 20 and project them onto different optical paths. For example, the beam splitting element 30 is configured to reflect one of the first polarized light 11 and the second polarized light 12 output from the phase modulation element 20 and transmit the other, so that the polarized light output from the beam splitting element 30 and the polarized light reflected by the beam splitting element 30 are on different optical paths. It should be noted that in the drawings of the present application, different filling patterns are used to distinguish the polarized light transmitted through the beam splitting element 30 and the polarized light reflected by the beam splitting element 30. Here, the different filling patterns are for clearly indicating the optical paths of the polarized light transmitted through the beam splitting element 30 and the polarized light reflected by the beam splitting element 30, and they do not represent specifically polarized light of a specific polarization direction.

[0062] Optionally, the beam splitting element 30 includes a reflector polarizer (RP), etc. The reflector polarizer can reflect polarized light vibrating in a certain specific direction and transmit polarized light vibrating perpendicular to this specific direction. For example, the reflector polarizer can reflect S-polarized light and transmit P-polarized light.

[0063] In some embodiments, continue to refer to Figure 1, at least part of the polarized light transmitted by the beam splitting element 30 and the polarized light reflected by the beam splitting element 30 is incident on the reflection element 40. The reflection element 40 includes a first mirror 41 and a second mirror 42. The first mirror 41 is configured to reflect the transmitted light of the beam splitting element 30 to the projection imaging medium 200 to display the near focal plane image 301. The second mirror 42 is configured to reflect the reflected light of the beam splitting element 30 to the first mirror 41. The first mirror 41 is further configured to reflect the reflected light of the second mirror 42 to the projection imaging medium 200 to display the far focal plane image 302. The far focal plane image 302 is located on the side of the near focal plane image 301 away from the projection imaging medium 200. Wherein, both the near focal plane image 301 and the far focal plane image 302 are virtual images, and the observer's eyes 400 can observe the near focal plane image 301 and the far focal plane image 302 through the projection imaging medium 200. The near focal plane image 301 and the far focal plane image 302 are located on different focal planes to achieve multi-focal plane display.

[0064] Optionally, the first mirror 41 includes a concave free-form mirror, and the second mirror 42 includes one of a plane mirror, a convex free-form mirror, and a concave free-form mirror. In this embodiment, the first mirror 41 includes a concave free-form mirror and the second mirror 42 is a plane mirror as an example for illustration.

[0065] In the display device 100 of this embodiment, the phase modulation element 20 converts the first polarized light 11 emitted by the image source 10 into the second polarized light 12 and emits it in the first stage, and transmits the first polarized light 11 in the second stage. The beam splitting element 30 reflects one of the first polarized light 11 and the second polarized light 12 emitted by the phase modulation element 20 and transmits the other. The first mirror 41 reflects the transmitted light of the beam splitting element 30 to the projection imaging medium 200 to display the near focal plane image 301, and reflects the reflected light of the beam splitting element 30 to the first mirror 41. The first mirror 41 also reflects the reflected light of the second mirror 42 to the projection imaging medium 200 to display the far focal plane image 302. In this way, through the cooperation of the phase modulation element 20, the beam splitting element 30, and the reflection element 40, a single image generation unit can be used to achieve multi-focal plane display, and there is no need to partition the image source 10, so that the resolution of the front and rear image planes located on different focal planes will not decrease, alleviating the problem of resolution decrease in the existing multi-focal plane AR-HUD display scheme using a single PGU and dual optical paths.

[0066] Specifically, in some embodiments, continue to refer to Figure 1, taking the first polarized light 11 as an S-polarized light and the second polarized light 12 as a P-polarized light as an example, the beam splitting element 30 is configured to reflect the first polarized light 11 and transmit the second polarized light 12. Specifically, the first polarized light 11 emitted by the image source 10 is an S-polarized light. The phase modulation element 20 converts the first polarized light 11 carrying the first image data into the second polarized light 12 carrying the first image data in the first stage and emits it from the phase modulation element 20. The second polarized light 12 carrying the first image data is a P-polarized light. The beam splitting element 30 transmits the second polarized light 12 carrying the first image data emitted from the phase modulation element 20. The first mirror 41 reflects the second polarized light 12 carrying the first image data transmitted from the beam splitting element 30 to the projection imaging medium 200 to display the near focal plane image 301; the phase modulation element 20 transmits the first polarized light 11 carrying the second image data in the second stage. The beam splitting element 30 reflects the first polarized light 11 carrying the second image data transmitted from the phase modulation element 20 to the second mirror 42. The second mirror 42 reflects the first polarized light 11 carrying the second image data to the first mirror 41. The first mirror 41 reflects the first polarized light 11 carrying the second image data to the projection imaging medium 200 to display the far focal plane image 302. In this way, the P-polarized light and the S-polarized light are projected onto the projection imaging medium 200 and then reflected to the eyes 400 to achieve near and far focal plane display.

[0067] Of course, the present application is not limited to this. In some other embodiments, the first polarized light 11 may also be a P-polarized light, then the second polarized light 12 is an S-polarized light, and the beam splitting element 30 is configured to reflect the first polarized light 11 and transmit the second polarized light 12; in some other embodiments, the beam splitting element 30 may also be configured to reflect the second polarized light 12 and transmit the first polarized light 11.

[0068] In some embodiments, referring to Figure 4 , Figure 4 is another schematic structural diagram of the display device 100 provided by the embodiment of the present application. Different from the Figure 1 exemplary display device 100, the display device 100 further includes a first dimming element 50 located on the light-emitting side of the beam splitting element 30. The first dimming element 50 is configured to convert the second polarized light 12 transmitted by the beam splitting element 30 into the first polarized light 11. Among them, the first polarized light 11 is an S-polarized light and the second polarized light 12 is a P-polarized light.

[0069] Optionally, the first dimming element 50 includes a half wave plate (HWP), etc. A half wave plate is also called a half-wave plate and is made of a birefringent crystal (such as quartz). A half wave plate can cause a relative phase delay between two polarization components of polarized light whose vibration directions are perpendicular to each other, thereby changing the polarization characteristics of light. When linearly polarized light is incident perpendicularly on the half wave plate, the two orthogonal polarization components (ordinary light o-light and extraordinary light e-light) of the polarized light have different propagation speeds in the crystal, thereby generating a phase difference. If the thickness of the half wave plate causes a phase delay that is an odd multiple of π between the ordinary light (o-light) and the extraordinary light (e-light), the polarization direction of the outgoing light will rotate by 2θ with respect to the incident light, where θ is the angle between the vibration direction of the incident light and the optical axis of the half wave plate. If θ = 45°, the vibration plane of the outgoing light is perpendicular to the vibration plane of the original incident light. That is, when θ = 45°, the half wave plate can rotate the polarization state by 90°. For example, the half wave plate can convert P-polarized light into S-polarized light.

[0070] Specifically, the first polarized light 11 emitted by the image source 10 is S-polarized light. The phase modulation element 20 converts the first polarized light 11 carrying the first image data into the second polarized light 12 carrying the first image data in the first stage and emits it from the phase modulation element 20. The second polarized light 12 carrying the first image data is P-polarized light. The beam splitting element 30 transmits the second polarized light 12 carrying the first image data emitted from the phase modulation element 20. The first dimming unit converts the second polarized light 12 carrying the first image data transmitted from the beam splitting unit into the first polarized light 11 carrying the first image data and emits it from the first dimming unit. The first mirror 41 reflects the first polarized light 11 carrying the first image data emitted from the first dimming unit to the projection imaging medium 200 to display the near focal plane image 301. In the second stage, the phase modulation element 20 transmits the first polarized light 11 carrying the second image data. The beam splitting element 30 reflects the first polarized light 11 carrying the second image data transmitted from the phase modulation element 20 to the second mirror 42. The second mirror 42 reflects the first polarized light 11 carrying the second image data to the first mirror 41. The first mirror 41 reflects the first polarized light 11 carrying the second image data to the projection imaging medium 200 to display the far focal plane image 302. In this way, the S-polarized light on the two optical paths is projected onto the projection imaging medium 200 and then reflected to the eyes 400 to achieve high-brightness near and far focal plane display.

[0071] In this embodiment, by providing the first dimming element 50, the second polarized light 12 transmitted by the beam splitting element 30 can be converted into the first polarized light 11, so as to increase the brightness of the near focal plane image 301. Specifically, the reflectivities of P-polarized light and S-polarized light on the projection imaging medium 200 differ significantly. The reflectivity of S-polarized light on the projection imaging medium 200 is close to 20%, but the reflectivity of P-polarized light on the projection imaging medium 200 is approximately between 2% and 3%. The reflectivity of P-polarized light is too low, making it difficult to view under strong light. The first dimming element 50 can convert the second polarized light 12 transmitted by the beam splitting element 30 into the first polarized light 11, that is, convert P-polarized light into S-polarized light, thereby increasing the brightness of the light entering the eye.

[0072] In this way, through the cooperation of the phase modulation element 20, the beam splitting element 30, the first dimming unit, and the reflection element 40, while achieving high-brightness multi-focal plane display, it is not necessary to partition and segment the image source 10, so that the resolution of the front and rear image planes located at different focal planes generated will not decrease, alleviating the problem of resolution decrease in the existing multi-focal plane AR-HUD display scheme using a single PGU and dual optical paths.

[0073] In some embodiments, referring to Figure 5 , Figure 5 FIG. is another structural schematic diagram of the display device 100 provided by the embodiment of the present application. Different from the Figure 4 display device 100 shown in the example, the second mirror 42 is of the same type as the first mirror 41, and the second mirror 42 is also a concave free-form mirror. Of course, in some other embodiments, the second mirror 42 may also be a convex free-form mirror.

[0074] In some embodiments, referring to Figure 6 and Figure 7 , Figure 6 FIG. is still another structural schematic diagram of the display device provided by the embodiment of the present application. Figure 7 FIG. Figure 6 is a partial detailed structural schematic diagram of the projection imaging medium 200 in Figure 6 . Referring to Figure 1The exemplary display device 100 is different in that a second light modulation element 60 is provided between the inner layer 201 and the outer layer 202 of the projection imaging medium 200, and the outer layer 202 is located on the side of the inner layer 201 away from the image source 10. Among them, the second light modulation element 60 is configured to convert the P-polarized light incident on the projection imaging medium 200 and transmitted through the inner layer 201 of the projection imaging medium 200 into S-polarized light, and convert the S-polarized light reflected by the outer layer 202 of the projection imaging medium 200 into P-polarized light to be transmitted through the inner layer 201 of the projection imaging medium 200, so as to increase the brightness of the P-polarized light entering the human eye. Optionally, the second light modulation element 60 includes a half-wave plate or the like.

[0075] Specifically, referring to Figure 6 , the first polarized light 11 emitted from the image source 10 is S-polarized light. In the first stage, the phase modulation element 20 converts the first polarized light 11 carrying the first image data into the second polarized light 12 carrying the first image data and emits it from the phase modulation element 20. The second polarized light 12 carrying the first image data is P-polarized light. The beam splitter 30 transmits the second polarized light 12 carrying the first image data emitted from the phase modulation element 20. The first mirror 41 reflects the second polarized light 12 carrying the first image data transmitted from the beam splitter 30 to the projection imaging medium 200 to display the near focal plane image 301; in the second stage, the phase modulation element 20 transmits the first polarized light 11 carrying the second image data. The beam splitter 30 reflects the first polarized light 11 carrying the second image data transmitted from the phase modulation element 20 to the second mirror 42. The second mirror 42 reflects the first polarized light 11 carrying the second image data to the first mirror 41. The first mirror 41 reflects the first polarized light 11 carrying the second image data to the projection imaging medium 200 to display the far focal plane image 302.

[0076] Combined with reference to Figure 6 and Figure 7, the projection imaging medium 200 includes an inner layer 201, an outer layer 202, and an interlayer 203 sandwiched between the inner layer 201 and the outer layer 202. Both the inner layer 201 and the outer layer 202 are made of glass, and the interlayer 203 is an adhesive layer for bonding the inner layer 201 and the outer layer 202 together. The second light modulating element 60 is disposed within the interlayer 203. When the first mirror 41 reflects the second polarized light 12 carrying the first image data transmitted from the beam splitting element 30 to the projection imaging medium 200, the reflectivity of the second polarized light 12 on the inner layer 201 is relatively low, especially near the Brewster angle, and the reflectivity of the second polarized light 12 approaches 0. Therefore, it can be approximately considered that the inner layer 201 has almost no reflection on the second polarized light 12, and almost all of the second polarized light 12 is transmitted from the inner layer 201 to the second light modulating unit. The second light modulating unit converts the second polarized light 12 transmitted from the inner layer 201 into the first polarized light 11. The converted first polarized light 11 exits the second light modulating unit and reaches the outer layer 202. The outer layer 202 reflects the first polarized light 11 exiting the second light modulating unit back to the second light modulating unit. The second light modulating unit then converts the first polarized light 11 reflected back from the outer layer 202 into the second polarized light 12. The converted second polarized light 12 exits the second light modulating unit and reaches the inner layer 201, and is transmitted from the inner layer 201 to reach the eye 400, thereby increasing the brightness of the light entering the eye.

[0077] When the first mirror 41 reflects the first polarized light 11 carrying the second image data reflected from the second mirror 42 to the projection imaging medium 200, the reflectivity of the first polarized light 11 on the inner layer 201 is relatively high, and the brightness of the light reaching the human eye is high. Part of the first polarized light 11 is transmitted from the inner layer 201 to the second light modulating unit. The second light modulating unit converts the transmitted first polarized light 11 into the second polarized light 12. The converted second polarized light 12 exits the second light modulating unit and reaches the outer layer 202. Since the reflectivity of the second polarized light 12 on the outer layer 202 is relatively low, the converted second polarized light 12 is transmitted from the outer layer 202 to eliminate the ghosting on different optical paths.

[0078] Thus, by disposing the second dimming unit in the interlayer 203 of the projection imaging medium 200, the P-polarized light on one optical path can be converted into S-polarized light by the second dimming unit and highly reflected on the outer layer 202 of the projection imaging medium 200, while the S-polarized light on the other optical path is highly reflected on the inner layer 201 of the projection imaging medium 200, so as to simultaneously achieve high-brightness imaging of S-polarized light and P-polarized light, thereby realizing high-brightness multi-focal plane display, and moreover, ghosting on different optical paths can be eliminated. Wherein, the second dimming unit can be disposed locally on the projection imaging medium 200 or on the entire surface area of the projection imaging medium 200.

[0079] Based on the same inventive concept, an embodiment of the present application further provides a vehicle, referring to Figure 8 , Figure 8 which is a partial schematic diagram of the vehicle provided by the embodiment of the present application. The vehicle includes a projection imaging medium 200 and the display device 100 according to one of the foregoing embodiments. The projection imaging medium 200 can be the front windshield of the vehicle. The display device 100 can transmit the outgoing light of the image source 10 through different optical paths to the projection imaging medium 200 to generate a near-focal plane image 301 and a far-focal plane image 302. The vehicle can be a sedan, a truck, a motorcycle, a bus, a ship, an airplane, a helicopter, a recreational vehicle, a playground vehicle, a tram, a golf cart, a train, etc., and the embodiment of the present application does not make a special limitation.

[0080] According to the above embodiments, it can be known that:

[0081] In a display device and a vehicle provided by the present application, a phase modulation element is disposed on the light-emitting side of the image source, and a beam splitting element is disposed on the light-emitting side of the phase modulation element. The phase modulation element converts the first polarized light emitted by the image source into the second polarized light and emits it in the first stage, and transmits the first polarized light in the second stage. The beam splitting element reflects one of the first polarized light and the second polarized light emitted by the phase modulation element and transmits the other. Thus, through the cooperation of the phase modulation element and the beam splitting element, the outgoing light of the image source can be transmitted to the projection imaging medium through different optical paths to generate a dual-focal plane image, and there is no need to partition the image source, so that the resolution of the front and rear image planes located at different focal planes generated will not decrease, alleviating the problem of resolution decrease in the existing multi-focal plane AR-HUD display scheme using a single PGU dual optical path.

[0082] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0083] The above has introduced the embodiments of the present application in detail. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display device, characterized in that, Comprising: An image source configured to emit first polarized light; A phase modulation element located on the light-emitting side of the image source, the phase modulation element being configured to convert the first polarized light into second polarized light and emit it in a first stage, and transmit the first polarized light in a second stage, the polarization direction of the first polarized light being different from the polarization direction of the second polarized light; A beam splitting element located on the light-emitting side of the phase modulation element, the beam splitting element being configured to reflect one of the first polarized light and the second polarized light emitted by the phase modulation element and transmit the other; A reflection element configured to reflect the reflected light of the beam splitting element and the transmitted light of the beam splitting element to a projection imaging medium to display a far focal plane image and a near focal plane image.

2. The display device according to claim 1, wherein One of the first polarized light and the second polarized light is S-polarized light and the other is P-polarized light.

3. The display device according to claim 2, wherein The first polarized light is S-polarized light, the second polarized light is P-polarized light, and the beam splitting element is configured to reflect the first polarized light and transmit the second polarized light.

4. The display device according to claim 3, characterized in that, The beam splitting element includes a reflective polarizing film.

5. The display device according to claim 3, characterized in that, The display device further includes a first light modulating element located on the light-emitting side of the beam splitting element, the first light modulating element being configured to convert the second polarized light transmitted by the beam splitting element into the first polarized light.

6. The display device according to claim 5, wherein The first light modulating element includes a half-wave plate.

7. The display device according to claim 2, wherein A second light modulating element is provided between the inner layer and the outer layer of the projection imaging medium, and the outer layer is located on the side of the inner layer away from the image source; Wherein, the second light modulating element is configured to convert the P-polarized light incident on the projection imaging medium and transmitted through the inner layer of the projection imaging medium into S-polarized light, and convert the S-polarized light reflected by the outer layer of the projection imaging medium into P-polarized light to be transmitted through the inner layer of the projection imaging medium.

8. The display device according to claim 7, wherein, The second light modulating element includes a half-wave plate.

9. The display device according to any one of claims 1 to 8, characterized in that, The reflection element includes a first mirror and a second mirror, the first mirror being configured to reflect the transmitted light of the beam splitting element to the projection imaging medium to display the near focal plane image, the second mirror being configured to reflect the reflected light of the beam splitting element to the first mirror, and the first mirror being further configured to reflect the reflected light of the second mirror to the projection imaging medium to display the far focal plane image, and the far focal plane image is located on the side of the near focal plane image away from the projection imaging medium.

10. The display device according to claim 9, wherein, The first mirror includes a concave free-form surface mirror, and the second mirror includes one of a plane mirror, a convex free-form surface mirror, and a concave free-form surface mirror.

11. The display device according to any one of claims 1 to 8, characterized in that, During a period when the image source displays an image, it includes at least one first sub-period and at least one second sub-period that alternate, and both the first sub-period and the second sub-period include at least one frame of picture; The first sub-period corresponds to the first stage, and the second sub-period corresponds to the second stage.

12. The display device according to claim 11, wherein, The phase modulation element includes one of a liquid crystal phase modulator, a piezoelectric type phase modulator, and a thermo-optical phase modulator.

13. The display device according to claim 12, wherein The phase modulation element is the liquid crystal phase modulator, and the phase modulation element includes a first electrode, a second electrode, and a liquid crystal layer located between the first electrode and the second electrode; When the phase modulation element is in the first stage, the liquid crystal molecules of the liquid crystal layer have a first arrangement state; when the phase modulation element is in the second stage, the liquid crystal molecules of the liquid crystal layer have a second arrangement state, and the second arrangement state is different from the first arrangement state.

14. A vehicle, characterized in that, It includes a projection imaging medium and the display device according to any one of claims 1 to 13.

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