Display device, cabin system, vehicle and wearable device

Abstract

The invention provides a display device, a cabin system, a vehicle and wearable equipment. The display device comprises a holographic optical element and an image source; the image source is positioned on one side of the holographic optical element and is used for generating multiple groups of image light which is alternately displayed; at least two groups of image light in the plurality of groups of image light comprise polychromatic light, and the same-color light of different groups of image light has different wavelengths; the holographic optical element is used for receiving the multiple sets of image light and is configured to enable the multiple sets of image light to be virtually imaged on different imaging planes, and the imaging planes are located on the other side of the holographic optical element. According to the display device, one image source can be utilized to generate a plurality of color images, and the plurality of color images are imaged at different depths through the holographic optical element, so that the display device flexibly adapts to the imaging environment, and the immersion feeling is high when the display device is used.

Description

Technical Field

[0001] The present application relates to the technical field of image display, and in particular, to a display device, a cockpit system, a vehicle, and a wearable device. Background Art

[0002] A head-up display (HUD) allows a driver to obtain real-time instrument information of a vehicle without looking down. An AR-HUD is a system that further integrates HUD with augmented reality (AR) technology. It can superimpose driving information such as road navigation, pedestrian prompts, vehicle distance confirmation, and lane departure warnings within the driver's line of sight, greatly improving the user's immersive visual experience and driving safety. It is an essential auxiliary display tool for future intelligent vehicles and other vehicles. Mainstream AR-HUDs usually form a virtual image at a relatively far distance from the vehicle. However, during driving, the formed virtual image is likely to overlap with the vehicle, thus significantly reducing the driving immersion. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a display device, a cockpit system, a vehicle, and a wearable device.

[0004] In a first aspect, the present application provides a display device, including a holographic optical element and an image source;

[0005] The image source is located on one side of the holographic optical element. The image source is used to generate multiple sets of image lights that are alternately displayed; at least two sets of the multiple sets of image lights include multi-color lights, and the wavelengths of the same-color lights in different sets of image lights are different;

[0006] The holographic optical element is used to receive the multiple sets of image lights. The holographic optical element is configured to respectively form virtual images of the multiple sets of image lights on different imaging planes, and the imaging planes are located on the other side of the holographic optical element.

[0007] In the present application, the display device of the present application can use one image source to generate multiple color images, and use the holographic optical element to image the multiple color images at different depths, so as to flexibly adapt to the imaging environment and provide a high immersion when the display device is used.

[0008] Exemplarily, a set of image light can include a single type of information or multiple types of information. For example, the image source can emit navigation information in the form of a set of image lights, emit vehicle information in the form of another set of image lights, and other information can also be emitted in the form of other image lights.

[0009] In addition, each group of image light can include multi-color light, and the wavelengths of different color lights are different. Among them, the light emitted by the image source can be spherical light or approximately spherical light, which is convenient for the holographic optical element to image. At this time, by making each group of image light include multi-color light, it is beneficial to realize the color imaging of each group of image light.

[0010] In this embodiment, by making the image source emit multiple groups of image light, the holographic optical element reflects the image light to the eye box position, so that the driver's eyes receive the image light, thereby forming a virtual image corresponding to the image light outside the holographic optical element, that is, forming a virtual reality image in front of the vehicle exterior, enabling the image information carried in the image light to be displayed outside the vehicle in front; in addition, since the image light has multiple color lights, the images displayed on each imaging plane are all in color, making the images more vivid; and since there are multiple groups of image light, multiple virtual reality images can be formed outside the vehicle. Different virtual reality images are in different positions and can display different information, which is easy to allocate display content and easy to integrate with or distinguish from the environment; therefore, by emitting vehicle information and assisted driving information and the like in the form of multiple groups of image light, this application is beneficial to separately display different information, is beneficial to clearly display different information, enables the virtual reality image generated by the display device to be displayed as a color image with different depths, thereby enhancing the driver's immersion.

[0011] In addition, in this embodiment, due to the wavelength selectivity of the holographic optical element, the natural light outside the vehicle hardly returns to the image source or the eye box through the holographic optical element, which can avoid the local high temperature of the image source and the glare effect on the human eye caused by the backflow of sunlight, so that the display device has strong anti-interference ability and high service life.

[0012] In some embodiments, the multi-color light includes at least two of red light, green light, and blue light.

[0013] Exemplarily, the multi-color light of a group of image light can include three primary colors of red light, green light, and blue light, that is, it includes three primary color lights. By controlling the brightness of red light, green light, and blue light of each pixel of the image source, the overall image light is a specific image. For example, the red light can be light with a wavelength in the range of 610 nm to 650 nm, the green light can be light with a wavelength in the range of 510 nm to 550 nm, and the blue light can be light with a wavelength in the range of 445 nm to 465 nm. In some other embodiments, the multi-color light of a group of image light can also include two of red light, green light, and blue light; or, the multi-color light of a group of image light can also include red light, green light, and blue light. In addition, a group of image light can also include white light.

[0014] In this embodiment, red light, green light, and blue light are three primary color lights, which are easy to make the image light present a color image.

[0015] In some embodiments, the exit positions and exit angles of multiple sets of image light are the same at the exit of the image source.

[0016] In this embodiment, by fixedly arranging the image source, the exit positions and exit angles of multiple sets of image light can be made the same. Therefore, when multiple sets of image light enter the human eye through the holographic optical element, the eye box positions of the multiple sets of image light are substantially the same, which is convenient for the imaging of multiple sets of image light, and the overall field of view angle of the multiple sets of image light is relatively large, and the range of the virtual image formed is large.

[0017] In some embodiments, the wavelength difference of the same-color light of multiple sets of image light is greater than or equal to 5 nm.

[0018] In this embodiment, the display device can reduce the mutual interference of the same-color light of different sets of image light during diffraction by the holographic optical element, and increase the longitudinal field of view angle of the corresponding color light at the eye box position, thereby enhancing the viewing range.

[0019] In some embodiments, the display frequency of each set of image light is greater than or equal to 25 Hz.

[0020] In this embodiment, by setting the display frequency of each set of image light, the images of each set of image light can be clearly imaged, and each image of the display device can be observed simultaneously.

[0021] In some embodiments, multiple sets of image light are imaged on multiple imaging planes one by one;

[0022] The multiple imaging planes are arranged in parallel; or, there is an included angle between at least two of the multiple imaging planes.

[0023] Among them, the imaging plane can be a plane that is substantially vertical, so that the imaging plane is perpendicular to the line of sight of the driver, which is easy for the driver to view the imaging content. Among them, the imaging plane can also be a plane that is substantially inclined, so that it is easy for the driver to observe the image of the imaging plane when the line of sight of the driver is inclined, or it is easy to make the image of the imaging plane blend with the environment.

[0024] In some embodiments, the polarization directions of the same-color light of at least two sets of image light among the multiple sets of image light are different.

[0025] Exemplarily, among the multiple sets of image light emitted by the image source, the wavelengths of the same-color light of some sets of image light are different and the polarization directions are also different, and / or, the wavelengths of the same-color light of some sets of image light are the same and the polarization directions are different; at this time, the holographic optical element has wavelength selectivity and polarization selectivity, and when multiple sets of image light are imaged through the holographic optical element, the same-color light with different polarization directions can be imaged on different imaging planes.

[0026] Exemplarily, at this time, photoanisotropic materials such as liquid crystals and liquid crystal polymers can be added to the material of the holographic optical element, which is beneficial to enabling the holographic optical element to have polarization selectivity for polarized light.

[0027] In this embodiment, since the bandwidth of the wavelength of a certain color light is limited, and there should be a certain difference in the wavelengths of the same-color light of different groups of image light, the number of groups of image light with the same-color light of different wavelengths is limited. By making the same-color light of different groups of image light have different polarizations, and using the wavelength selectivity and polarization selectivity of the holographic optical element, the number of groups of image light breaks through the limitation of the bandwidth of the wavelength of the color light, enabling the image light to have more groups, so that it can be imaged on more imaging planes, and making the display device have more diverse imaging options and a more three-dimensional imaging effect.

[0028] In some embodiments, the number of image light is in the range of 2 to 10; or

[0029] The holographic optical element has wavelength selection characteristics and polarization selection characteristics. The number of image light is M×N groups. Among the M×N groups of image light, there are M groups of image light with the same-color light of the same polarization direction and different wavelengths, and there are N groups of image light with the same-color light of the same wavelength and different polarization directions. M is a positive integer in the range of 2 to 10, and N is a positive integer in the range of 2 to 4.

[0030] Exemplarily, the virtual images of the M×N groups of image light can cooperate with each other. For example, a three-dimensional stereoscopic image can be formed, making the display device have a more realistic three-dimensional display effect.

[0031] In this embodiment, by reasonably setting the number of image light, the manufacturing difficulty of the display device can be reduced, and the display device can have a more realistic display effect.

[0032] In some embodiments, the holographic optical element includes X layers of thin films. The X layers of thin films are stacked. The number of layers of the thin films is related to the number of groups of image light. X is a positive integer.

[0033] In this embodiment, exemplarily, when the holographic optical element has a single layer of thin film, the light of different wavelengths emitted by the image source is diffracted and imaged through the single layer of thin film, and the single layer of thin film is prepared based on the light of each wavelength emitted by the image source. At this time, the holographic optical element is relatively thin and light. In some other examples, when the holographic optical element has multiple layers of thin films, the multiple layers of thin films can be prepared separately, and wavelength allocation can be performed on each layer of thin film, so that each layer of thin film has a grating structure with wavelength selectivity for the corresponding wavelength, so that each layer of thin film only diffracts a part of the light of a certain wavelength, and the multiple layers of thin films cooperate with each other to diffract the light of each wavelength emitted by the image source, so as to image multiple groups of image light separately.

[0034] In some embodiments, the image light generated by the image source includes Y sets of image light, and the holographic optical element includes Y layers of thin films, with one layer of thin film for imaging a corresponding set of image light, where Y is a positive integer in the range of 2 to 10.

[0035] In this embodiment, each layer of the thin film of the holographic optical element requires a small number of lights with different wavelengths to be diffracted, and the refractive index modulation degree of each layer of the thin film is high, so that the brightness of the final image is high and the imaging effect is good.

[0036] In some embodiments, at least two sets of the multiple sets of image light are reflected by the holographic optical element to different eyebox positions for observation and imaging at different eyebox positions.

[0037] In this embodiment, based on the wavelength selectivity and angle selectivity of the holographic optical element, at least two sets of image light are reflected to different eyebox positions. Different observers (such as drivers and passengers) can observe at different eyebox positions respectively, so as to receive different image lights respectively. The different image lights are imaged respectively, realizing virtual reality images provided for different observers by one image source respectively, and meeting the different needs of different observers.

[0038] In some embodiments, the materials of the holographic optical element include one or more of silver salt dry plate, photopolymer, dichromated gelatin, photorefractive material, photochromic material, photoanisotropic material, etchant, liquid crystal, liquid crystal polymer, and metasurface.

[0039] In a second aspect, the present application provides a cockpit system, which includes an intelligent driving module and a display device provided in any of the above embodiments. The image source of the display device is electrically connected to the intelligent driving module, and the intelligent driving module is used to control the display content of the image source.

[0040] In this embodiment, the intelligent driving module can communicate with the display device. For example, the intelligent driving module can implement corresponding assisted driving strategies according to the driving environment, and display the assisted driving information (such as automatic braking, automatic parking, lane keeping, pedestrian detection, etc.) through the display device in the form of virtual reality images, so that the driver can see the corresponding information without lowering the head, thereby giving the driver a strong sense of immersion when driving.

[0041] In a third aspect, the present application further provides a vehicle, including:

[0042] A housing;

[0043] A windshield installed on the housing; and

[0044] The display device provided in any of the above embodiments, where the image source of the display device is installed inside the housing, and the holographic optical element of the display device is installed on the windshield.

[0045] In this embodiment, during normal driving, the driver can obtain vehicle information and assisted driving information in the image light within the field of vision, and can obtain the information required for driving without looking down at the instrument panel, providing the driver with a better driving experience and enhancing driving safety and immersion.

[0046] In some embodiments, the holographic optical element is fixed to one side of the windshield facing the inside of the housing; alternatively, the holographic optical element is embedded inside the windshield.

[0047] In this embodiment, by setting the installation method of the holographic optical element, the holographic optical element is easy to install or the fixation of the holographic optical element is more reliable.

[0048] Fourthly, the present application also provides a wearable device, including:

[0049] A frame;

[0050] Lenses, installed on the frame; and

[0051] A display device as provided in any of the above embodiments, wherein the image source of the display device is installed on the inner side of the frame, and the holographic optical element of the display device is installed on the lens.

[0052] In some examples, the AR glasses can be applied to a means of transportation. The AR glasses can be worn by the driver, and the AR glasses can display the driving information of the means of transportation and / or the information of the means of transportation itself. For example, when the means of transportation is a vehicle, the AR glasses are used to display vehicle information or assisted driving information. In this example, when the driver wears the AR glasses, it is easier to see the corresponding information, and the driver has a higher degree of freedom of the head and a better driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to illustrate the technical solutions in the embodiments of the present application or the background art, the following will describe the drawings required to be used in the embodiments of the present application or the background art.

[0054] Figure 1 is a schematic structural diagram of a means of transportation provided by the present application;

[0055] Figure 2 is Figure 1 a schematic structural diagram of the windshield and the holographic optical element shown in some embodiments;

[0056] Figure 3 is Figure 1 a schematic structural diagram of the windshield and the holographic optical element shown in some other embodiments;

[0057] Figure 4 is a schematic internal structural diagram of a cockpit system provided by an embodiment of the present application;

[0058] Figure 5 is a schematic structural diagram of a wearable device provided by this application;

[0059] Figure 6 is Figure 1 a schematic structural diagram of the display device shown in some embodiments;

[0060] Figure 7 is Figure 6 a schematic structural diagram of the configuration principle of the holographic optical element shown in some embodiments;

[0061] Figure 8 is Figure 6 a schematic structural diagram of the display device shown in some embodiments;

[0062] Figure 9 is Figure 8 a schematic structural diagram of the display device shown in some other embodiments;

[0063] Figure 10 is Figure 6 a schematic structural diagram of the display device shown in some other embodiments;

[0064] Figure 11 is Figure 6 a schematic structural diagram of the display device shown in some other embodiments;

[0065] Figure 12 is Figure 6 a schematic structural diagram of the display device shown in some other embodiments;

[0066] Figure 13 is Figure 6 a schematic structural diagram of the display device 10 shown in another embodiment;

[0067] Figure 14 is Figure 13 a schematic structural diagram of the display device 10 shown in some embodiments;

[0068] Figure 15 is Figure 14 another schematic structural diagram of the display device 10 shown;

[0069] Figure 16 is Figure 13 a schematic structural diagram of the display device 10 shown in some other embodiments. Detailed implementation manners

[0070] The embodiments of this application will be described below with reference to the accompanying drawings in the embodiments of this application.

[0071] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation" and "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Plurality" means at least two.

[0072] The directional terms mentioned in the embodiments of the present application, such as "upper", "lower", "inner", "outer", "top", "bottom", "side", etc., are only with reference to the direction of the accompanying drawings. Therefore, the directional terms used are for better and clearer description and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the embodiments of the present application.

[0073] In the embodiments of the present application, the limitations on the relative position relationship are mentioned, such as parallel, perpendicular, alignment, etc. These limitations are all in view of the current technological level and are not absolutely strict limitations. A small deviation is allowed, and approximate parallel, approximate perpendicular, approximate alignment, etc. are all acceptable. For example, when A is parallel to B, it means that A is parallel to B or approximately parallel, and the included angle between A and B can be between 0 degrees and 10 degrees. For example, when A is perpendicular to B, it means that A is perpendicular to B or approximately perpendicular, and the included angle between A and B can be between 80 degrees and 100 degrees.

[0074] In the embodiments of the present application, the terms "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", "fourth" can explicitly or implicitly include one or more of such features.

[0075] In the embodiments of the present application, the limitations on the range mentioned can include the endpoints of the range. For example, within the range from "A" to "B", the values of the endpoints "A" and "B" are included.

[0076] The present application provides a display device. The display device includes an image source and a holographic optical element; the image source is located on one side of the holographic optical element, and the image source is used to generate multiple sets of image light for alternate display; at least two sets of the multiple sets of image light include multicolor light, and the wavelengths of the same-color light in different sets of image light are different; the holographic optical element is used to receive the multiple sets of image light, and the holographic optical element is configured to respectively form virtual images of the multiple sets of image light on different imaging planes, and the imaging planes are located on the other side of the holographic optical element. The display device of the present application can use one image source to generate multiple color images, and perform imaging of the multiple color images at different depths through the holographic optical element to flexibly adapt to the imaging environment, so that the display device has a high sense of immersion when in use.

[0077] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle 100 provided by this application.

[0078] In some embodiments, the vehicle 100 may be a device such as a vehicle, a ship, an aircraft, etc. In this embodiment, the vehicle is mainly taken as an example for illustrative purposes.

[0079] Exemplarily, the vehicle 100 may include a display device 10, a housing 20, and a windshield 30.

[0080] Among them, the housing 20 may be the shell of the vehicle. The vehicle may be an electric vehicle, a fuel vehicle, a hybrid vehicle, etc., and this embodiment does not strictly limit this. For example, power devices such as engines and electric motor powertrains may be installed inside the housing 20, energy devices such as batteries may also be installed, as well as control systems, etc., so that the vehicle can operate. This embodiment will not list them one by one.

[0081] Among them, the windshield 30 may be installed on the housing 20. For example, the windshield 30 may be installed at a position corresponding to the front of the vehicle's cab on the housing 20. The windshield 30 and the housing 20 isolate the cab from the outside of the vehicle, so as to facilitate the driver to drive the vehicle and protect the driver. The windshield 30 may be made of transparent materials such as glass and plastic, so that the environmental information outside the vehicle can be transmitted through the windshield 30 into the cab to meet the normal driving needs.

[0082] Among them, the display device 10 may be installed inside the vehicle 100. The display device 10 may emit image light, and the image light may be used to display vehicle information or assisted driving information. For example, the image light may display one or more of the vehicle's driving speed, driving mileage, fuel level, battery level, and lamp status, etc. The image light may also display one or more of the navigation direction, navigation route, remaining mileage, remaining time, etc. of the navigation information, and, the image light may also display one or more of the external vehicles, external lane safety distance, surrounding obstacles, and reverse image, etc. of the environmental information; among them, the navigation information and the environmental information may be assisted driving information, but the information that the image light can display is not limited to the above-mentioned vehicle information and assisted driving information.

[0083] In addition, the image light of the display device 10 may enter the driver's eyes and form a virtual image in front of the outside of the vehicle, so as to display the vehicle information and assisted driving information of the image light, which is equivalent to imaging the information on the dashboard outside the vehicle. At this time, during normal driving, the driver can obtain the vehicle information and assisted driving information in the image light within the field of vision, and can obtain the driving required information without looking down at the dashboard, so that the driver has a better driving experience and improves driving safety and immersion.

[0084] Please refer to Figures 1 to 3 , Figure 2 which Figure 1 is a schematic structural diagram of the windshield 30 and the holographic optical element 2 in some embodiments. Figure 3 which Figure 1 is a schematic structural diagram of the windshield 30 and the holographic optical element 2 in some other embodiments.

[0085] In some embodiments, the display device 10 may include an image source 1 and a holographic optical element 2.

[0086] In some examples, the image source 1 may be installed inside the housing 20, for example, at a position corresponding to the front of the cab inside the housing 20. For example, the vehicle 100 may include an instrument panel, and the image source 1 may be fixed to the instrument panel. Exemplarily, the holographic optical element 2 may be installed on the windshield 30. The image source 1 is used to emit image light, and the image light emitted by the image source 1 may directly irradiate the holographic optical element 2, or irradiate the holographic optical element 2 through an optical component. The holographic optical element 2 is used to perform holographic display on the image light.

[0087] Exemplarily, as Figure 2 shown, the holographic optical element 2 may be attached to the side of the windshield 30 facing the interior of the vehicle. At this time, the holographic optical element 2 is easy to install.

[0088] Exemplarily, as Figure 3 shown, the holographic optical element 2 may also be embedded in the interlayer of the windshield 30. For example, the windshield 30 generally has a multi-layer structure and may include an inner layer 301 and an outer layer 302. The holographic optical element 2 may be disposed between the inner layer 301 and the outer layer 302 of the windshield 30, and the holographic optical element 2 may connect the inner layer 301 and the outer layer 302. At this time, the inner layer 301 and the outer layer 302 sandwich the holographic optical element 2, making the fixation of the holographic optical element 2 more reliable.

[0089] Exemplarily, the holographic optical element 2 may be curved. The windshield 30 generally has a substantially curved shape, and the shape of the holographic optical element 2 may be the same as the shape of the windshield 30 to which it is attached, so that the holographic optical element 2 can be directly installed on the windshield 30 without additional design of the shape of the holographic optical element 2. In some other embodiments, the holographic optical element 2 may also be planar. At this time, the holographic optical element 2 is easy to manufacture and the imaging is not prone to distortion.

[0090] Please refer to Figure 4 , Figure 4 which

[0091] In some embodiments, the cockpit system 200 can be applied to a vehicle 100 (see Figure 1 ), and the cockpit system 200 can be used to be controlled by a driver so as to control the vehicle 100 and enable the vehicle 100 to operate normally.

[0092] The cockpit system 200 can include a cabin body 40, a windshield 30, a display device 10, and an intelligent driving module 50. The windshield 30 can be fixedly installed on the cabin body 40.

[0093] Exemplarily, the display device 10 can include an image source 1 and a holographic optical element 2. The structure of the display device 10 can refer to the corresponding description of the Figure 1 embodiment, and this embodiment will not elaborate thereon. Among them, the image source 1 of the display device 10 can be electrically connected to the intelligent driving module 50. The intelligent driving module 50 is used to control the display content of the image source 1, and the holographic optical element 2 can be installed on the windshield 30.

[0094] In some embodiments, the intelligent driving module 50 can be an Advanced Driver Assistance Systems (ADAS). The intelligent driving module 50 can be used to assist the driver in driving the vehicle 100, including functions such as automatic braking, automatic parking, lane keeping, and pedestrian detection.

[0095] In some examples, the cockpit system 200 can further include an instrument panel 60 and a seat 70. Among them, the intelligent driving module 50 and the image source 1 can be installed inside the instrument panel 60. The seat 70 can be located inside the cabin body 40. The seat 70 can be arranged facing the instrument panel 60, and there can be an operation space between the seat 70 and the instrument panel 60 to facilitate the driver's operation.

[0096] In this embodiment, the intelligent driving module 50 can communicate with the display device 10. For example, the intelligent driving module 50 can implement corresponding assisted driving strategies according to the driving environment and display the assisted driving information (such as automatic braking, automatic parking, lane keeping, pedestrian detection, etc.) through the display device 10 in the form of virtual reality images, so that the driver can see the corresponding information without lowering the head, thereby enabling the driver to have a strong sense of immersion when driving.

[0097] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of a wearable device 300 provided by this application.

[0098] In some embodiments, the wearable device 300 can be an AR glasses.

[0099] Exemplarily, the AR glasses can include a display device 10, a frame 80, and lenses 90.

[0100] Among them, the spectacle frame 80 may include a spectacle frame 801 and temple arms 802, and the temple arms 802 may be rotatably connected to the spectacle frame 801. The spectacle frame 801 may have two hollowed-out areas, and two temple arms 802 may be symmetrically arranged relative to the spectacle frame 801, and the temple arms 802 can be folded and opened relative to the spectacle frame 801. Among them, the materials of the spectacle frame 801 and the temple arms 802 may be plastic or metal, and the materials of the spectacle frame 801 and the temple arms 802 may be the same or different.

[0101] Among them, the lens 90 may be fixedly installed on the spectacle frame 80. The shape of the lens 90 may be adapted to the hollowed-out area of the spectacle frame 801, and the lens 90 may be snap-fitted or adhered in the spectacle frame 801. The lens 90 may be made of a transparent material such as plastic or glass for transmitting light.

[0102] Among them, the display device 10 may include a holographic optical element 2 and an image source 1. The holographic optical element 2 may be installed on the lens 90, and the image source 1 may be installed on the spectacle frame 801 of the spectacle frame 80 and located inside the spectacle frame 80, that is, on the side close to the human eye when the AR glasses are worn, so that the image light emitted by the image source 1 can be reflected to the human eye through the holographic optical element 2 and form a virtual image outside the AR glasses. The image light emitted by the image source 1 may include device information and application information, but is not limited thereto. Exemplarily, the device information may include the battery information, brightness information, and volume information of the AR glasses, etc., and the application information may include navigation information, game information, video information, etc.

[0103] In some examples, the AR glasses can be applied to a vehicle 100 (please refer to Figure 1 ), the AR glasses can be worn by the driver, and the AR glasses can display the driving information of the vehicle 100 and / or the information of the vehicle 100 itself. For example, when the vehicle 100 is a vehicle, the AR glasses are used to display vehicle information or assisted driving information. For specific details, reference can be made to Figure 1 the relevant descriptions of the embodiments. This embodiment will not be elaborated herein. In this example, when the driver wears the AR glasses, it is easier to see the corresponding information required for driving, and the driver has a higher degree of head freedom and a better driving experience.

[0104] The structural principle of the display device 10 of the wearable device 300 in this embodiment can be basically the same as that of Figure 1 the display device 10 in the embodiment.

[0105] The following mainly takes the display device in a vehicle as an example for illustration.

[0106] Please refer to Figure 6 , Figure 6 which Figure 1 is a schematic structural diagram of the display device 10 in some embodiments. Among them,Figure 6 The perspective can be the perspective of viewing the display device 10 from the side.

[0107] In some embodiments, the image source 1 can be located on one side of the holographic optical element 2, and the image source 1 can generate multiple sets of image light. In some examples, the information included in each set of image light can be different. Among them, the image light can enter the eyebox 4 through the holographic optical element 2 and be imaged on the imaging plane 3. Among them, the eyebox 4 can refer to the area where the human eye can clearly see the entire virtual image. Generally speaking, the human eye can move within the eyebox 4.

[0108] Exemplarily, a set of image light can include a single type of information or multiple types of information. For example, the image source 1 can emit navigation information in the form of a set of image light, emit vehicle information in the form of another set of image light, and other information can also be emitted in the form of other image light. This example is not strictly limited in this regard.

[0109] In addition, each set of image light can include multi-color light, and the wavelengths of different color lights are different. Among them, the light emitted by the image source 1 can be spherical light or approximately spherical light to facilitate imaging by the holographic optical element 2. At this time, by making each set of image light include multi-color light, it is beneficial to achieve color imaging of each set of image light.

[0110] Exemplarily, the multi-color light of a set of image light can include three types: red light, green light, and blue light, that is, including the three primary color lights. By controlling the brightness of the red light, green light, and blue light of each pixel of the image source 1, the overall image light becomes a specific image. Red light, green light, and blue light are the three primary color lights, which are easy to present a color image. For example, the red light can be light with a wavelength in the range of 610 nm to 650 nm, the green light can be light with a wavelength in the range of 510 nm to 550 nm, and the blue light can be light with a wavelength in the range of 445 nm to 465 nm. In some other embodiments, the multi-color light of a set of image light can also include two of red light, green light, and blue light; or, the multi-color light of a set of image light can also include red light, green light, and blue light. In addition, a set of image light can also include white light.

[0111] Exemplarily, the wavelengths of the same-color lights of different sets of image light are different. For example, including two sets of image light, both sets of image light have red light, and the wavelengths of the red light in the two sets of image light are different.

[0112] Among them, the difference in the wavelengths of the same-color lights of different sets of image light can be greater than or equal to 5 nm to reduce the mutual interference of the same-color lights of different sets of image light during diffraction by the holographic optical element 2 and improve the longitudinal field of view angle of the corresponding color light at the position of the eyebox 4, thereby enhancing the viewing range. In some other implementations, the difference in the wavelengths of different sets of image light can also be less than 5 nm. For example, it can be in the range of 2 nm to 5 nm.

[0113] In some examples, the number of multiple groups of image light can be in the range of 2 to 10. Among them, the bandwidth of one color light is limited. When the wavelength difference of the same-color light of different groups of image light is determined, the number of groups of image light can be determined. By reasonably setting the number of image light, the manufacturing difficulty of the display device 10 can be reduced. Or, in some other examples, when other characteristics (such as the polarization characteristics in the embodiments hereinafter Figure 11 or Figure 12 are introduced into the multiple groups of image light), the number of groups of image light may not be limited to this.

[0114] Exemplarily, the image source 1 can alternately display multiple groups of image light. The image source 1 can alternately display multiple groups of image light through a time-sharing strategy, that is, generate and display multiple groups of image light in sequence in time. Among them, only one group of image light can be displayed at the same moment. When different groups of image light are alternately displayed, the display of each group of image light is independent in time. In this example, when the image light of each group satisfies the frame rate that causes the human eye to achieve the visual persistence effect, then each group of image light can be continuously displayed, and there will be no ghosting between the virtual images formed by different image lights, so as to achieve the effect that multiple groups of image light are simultaneously imaged visually.

[0115] Exemplarily, the display frequency of multiple groups of image light can be greater than or equal to 25 Hz, that is, the frame rate of the image light can be greater than or equal to 25 frames. Among them, the frame rates of multiple groups of image light can be the same to make the modulation strategy of multiple groups of image light simpler; in some other examples, the frame rates of multiple groups of image light can also be different. For example, among multiple groups of image light, for the content that needs to be dynamically displayed, the frame rate can be modulated relatively large; for the content that is statically displayed, the frame rate can be modulated relatively small. In this example, by setting the display frequency of each group of image light, the images of each group of image light can be clearly imaged, and each image of the display device 10 can be observed simultaneously.

[0116] Exemplarily, the emission positions and emission angles of multiple groups of image light of the image source 1 can be the same. Among them, multiple groups of image light can all be generated and emitted by the same image source 1, and multiple groups of image light can all be spherical light. By fixedly setting the image source 1, the emission positions and emission angles of multiple groups of image light can be the same. Therefore, when multiple groups of image light enter the human eye through the holographic optical element 2, the positions of the eye box 4 of multiple groups of image light are basically the same, which is convenient for the imaging of multiple groups of image light, and the overall field of view angle of multiple groups of image light is relatively large, and the range of the virtual image formed is large.

[0117] Exemplarily, the image source 1 can be a projection image source or a multi-wavelength light source. For example, the projection image source can include a Digital Light Procession (DLP) projector, a Liquid Crystal on Silicon (LCoS) projector, a Thin film transistor liquid crystal display (TFT-LCD) projector, a Micro Light Emitting Diode (Micro-LED) projector, a Micro Organic Light-Emitting Diode (Micro-OLED), etc. For example, the multi-wavelength light source can include a multi-color LED light source, a multi-color laser light source, a supercontinuum light source, a continuously tunable light source, etc.

[0118] In some embodiments, the holographic optical element 2 (HOE) is an optical element made according to the principle of holography. The holographic optical element 2 can be a thin film structure, i.e., the HOE film. The holographic optical element 2 can perform imaging based on the diffraction principle, and its imaging characteristics vary with wavelength, having wavelength selectivity.

[0119] Among them, the material of the holographic optical element 2 can be one or more of silver salt dry plate, photopolymer, dichromated gelatin, photorefractive material, photochromic material, photoanisotropic material, etchant, liquid crystal, liquid crystal polymer, metasurface. No further examples are given for the material of the holographic optical element 2 in this example.

[0120] In some examples, the holographic optical element 2 can be configured to form virtual images of multiple sets of image light on different imaging planes 3 respectively. The imaging plane 3 is located on the other side of the holographic optical element 2 away from the image source 1. Among them, the holographic optical element 2 is used to receive multiple sets of image light emitted by the image source 1 and perform imaging on multiple sets of image light respectively based on its own grating structure. It can be understood that the grating structure of the holographic optical element 2 can be formed by preparation. Therefore, when preparing the holographic optical element 2, according to its imaging requirements for multiple sets of image light in the optical path of the display device 10, the corresponding grating structure can be formed.

[0121] Among them, the number of thin films of the holographic optical element 2 can be X layers, and the X layers of thin films are stacked. The number of thin film layers is related to the number of sets of image light. X is a positive integer. For example, the number of thin films of the holographic optical element 2 can be one layer (please refer to Figure 2 ), and at this time the holographic optical element 2 is a single-layer multiplexing thin film. The number of thin films of the holographic optical element 2 can be multiple layers (please refer to Figure 3) The multilayer films can be stacked in sequence, and in this case, the holographic optical element 2 is the multilayer stacked films.

[0122] Exemplarily, when the holographic optical element 2 has a single-layer film, the light of different wavelengths emitted by the image source 1 is diffracted and imaged through the single-layer film, and the single-layer film is prepared based on the light of each wavelength emitted by the image source 1. At this time, the holographic optical element 2 is relatively thin and light. In some other examples, when the holographic optical element 2 has multilayer films, the multilayer films can be prepared separately, and wavelength allocation can be performed on each layer of film, so that each layer of film has a grating structure with wavelength selectivity for the corresponding wavelength, so that each layer of film only diffracts the light of a part of the wavelengths. The multilayer films cooperate with each other to diffract the light of each wavelength emitted by the image source 1, so as to image multiple sets of image lights separately. It can be understood that the maximum value of the number X of the multilayer films can be the same as the sum of the number of color lights included in each group of image lights among the multiple sets of image lights; for example, there are 3 sets of image lights, and each set of image lights includes 3 kinds of light, then the maximum value of X can be 9, that is, the holographic optical element 2 can have at most 9 layers of films.

[0123] In some examples, the number of the multilayer films can be the same as the number of groups of the image lights. For example, when the image lights generated by the image source 1 include Y groups of image lights, the holographic optical element 2 can include Y layers of films, and one layer of film is used to image a group of corresponding image lights. Y can be a positive integer in the range of 2 to 10. For example, when the image lights generated by the image source 1 are 3 groups, the holographic optical element 2 can include 3 layers of films. At this time, the number of lights of different wavelengths that each layer of film of the holographic optical element 2 needs to diffract is small, and the refractive index modulation degree of each layer of film is high, so that the brightness of the final image is high and the imaging effect is good.

[0124] Among them, the imaging plane 3 is a virtual plane, and the imaging plane 3 can be determined when preparing the holographic optical element 2 based on the requirements of the display device 10.

[0125] Exemplarily, the number of the imaging planes 3 can correspond to the number of groups of the image lights, and a group of image lights can be imaged on an imaging plane 3. At this time, since the driver's line of sight often falls in front of the vehicle, the information that needs to be viewed in real time, such as navigation information, can be imaged on the imaging plane 3 at a relatively far distance, and the imaging plane 3 at a relatively far distance has a larger field of view, which is also convenient for displaying navigation information, etc. The navigation information is easy to be integrated with the road at this time; the imaging plane 3 at a relatively close distance is not easily interfered by the environment, and the viewing frequency by the driver is relatively low, and it can be resident on the imaging plane 3 at a relatively close distance to display vehicle information, which is easy for the driver to view the vehicle information. It can be understood that the display contents between the multiple imaging planes 3 can be independent of each other or can be related to each other and can be set according to requirements. In addition, the display methods of information such as navigation information and vehicle information are not limited to the above situations and can be set according to requirements.

[0126] Exemplarily, the distances of multiple imaging planes 3 from the holographic optical element 2 can be different. For example, the imaging plane 3 closer to the holographic optical element 2 can be within one meter, and the imaging plane 3 farther from the holographic optical element 2 can be within 100 meters, but this is not limiting. In some other examples, among the multiple imaging planes 3, there may also be different imaging planes 3 with the same distance from the holographic optical element 2, and this example does not make specific limitations on this.

[0127] Exemplarily, multiple imaging planes 3 can be parallel to each other; or, there is an included angle between at least two of the multiple imaging planes 3. Among them, the imaging plane 3 can be a plane that is roughly vertical, so that the imaging plane 3 is perpendicular to the line of sight of the driver, making it easy for the driver to view the imaging content. Among them, the imaging plane 3 can also be a plane that is roughly inclined, so that it is easy for the driver to observe the image of the imaging plane 3 when the line of sight of the driver is inclined, or it is easy to make the image of the imaging plane 3 blend with the environment.

[0128] In this embodiment, by making the image source 1 emit multiple sets of image light, the holographic optical element 2 reflects the image light to the position of the eye box 4, enabling the eyes of the driver to receive the image light, thereby forming a virtual image corresponding to the image light outside the holographic optical element 2, that is, forming a virtual reality image in front of the vehicle exterior, so that the image information carried in the image light can be displayed outside the vehicle in front; in addition, since the image light has multiple color lights, the images displayed on each imaging plane 3 are all in color, making the images more vivid; and since there are multiple sets of image light, multiple virtual reality images can be formed outside the vehicle, and different virtual reality images are in different positions and can display different information, which is easy to allocate display content and easy to blend with or distinguish from the environment; therefore, by emitting vehicle information, assisted driving information, etc. in the form of multiple sets of image light, this application is conducive to separately displaying different information, is conducive to clearly displaying different information, enabling the virtual reality image generated by the display device 10 to be displayed as a color image with different depths, thereby enhancing the immersion feeling of the driver.

[0129] In addition, in this embodiment, due to the wavelength selectivity of the holographic optical element 2, the natural light outside the vehicle hardly returns to the image source 1 or the eye box 4 through the holographic optical element 2, which can avoid the local high temperature of the image source 1 and the glare effect on the human eye caused by the backflow of sunlight, thereby making the display device 10 have strong anti-interference ability and high lifespan.

[0130] In some other embodiments, the display device 10 may further include other optical elements for correcting aberration or deflecting light beams. These optical elements may be located in the optical path between the image source 1 and the holographic optical element 2. For example, these optical elements may include one or more of a plane mirror, a parallel plate, a free-form mirror, a prism, a spherical mirror, and a cylindrical mirror, which can be set according to requirements, and this embodiment does not strictly limit this.

[0131] Please refer to Figure 6 and Figure 7 , Figure 7 is Figure 6 a schematic structural diagram of the configuration principle of the holographic optical element 2 shown in some embodiments.

[0132] In the embodiments of the present application, the holographic optical element 2 can be prepared by any one of an exposure method, an electron beam lithography method, or a nanoimprint method.

[0133] In some embodiments, the holographic optical element 2 can be configured by an exposure method to form a grating structure on the holographic optical element 2, so that in the display device 10, the holographic optical element 2 can image multiple sets of image lights on different imaging planes 3 respectively.

[0134] Exemplarily, the exposure optical path can be correspondingly set based on the display optical path of the display device 10, so that the holographic optical element 2 has wavelength selectivity for light of a specific wavelength.

[0135] For example, the light emitted by the exposure light source can be split into a reference light and an object light. The reference light is emitted from a first position on one side of the holographic optical element 2 towards the holographic optical element 2, and the object light is emitted from a second position on the other side of the holographic optical element 2 towards the holographic optical element 2. The reference light and the object light irradiate the holographic optical element 2 to form a grating structure on the holographic optical element 2, thereby realizing a single exposure of the holographic optical element 2. Among them, in a single exposure, the exposure light source can emit a light beam of a single wavelength, and the wavelength of the light beam is the same as the wavelength of the image source 1. Among them, the distance and angle between the first position of the exposure optical path and the holographic optical element 2 can correspond to the distance and angle between the imaging plane 3 of the color light of this wavelength in the display device 10 and the holographic optical element 2. Among them, the distance and angle between the second position in the exposure optical path and the holographic optical element 2 can correspond to the distance and angle between the image source 1 and the holographic optical element 2 in the display device 10. In some examples, the object light and the reference light are spherical lights. In some other examples, one of the object light or the reference light can be a plane light.

[0136] Among them, since the image source 1 of the display device 10 can emit multiple sets of image lights, and each set of image lights includes multiple color lights, the holographic optical element 2 needs to be exposed to each color light of each set of image lights respectively.

[0137] It is understandable that the light beam used to expose the holographic optical element 2 may not contain image information, and the wavelength during exposure may correspond to the same characteristics (such as wavelength characteristics) of the light emitted by the image source 1. In some other implementations, when the light emitted by the image source 1 has a polarization characteristic in addition to the wavelength characteristic (such as the polarization characteristic described below), Figure 11 or Figure 12 In the embodiment, different groups of image lights have different polarization directions, and when exposing the holographic optical element 2, light beams with the same wavelength and polarization direction may be used for exposure.

[0138] Some embodiments of the display device 10 are described below by way of examples.

[0139] See also Figure 8 , Figure 8 yes Figure 6 The illustrated structure of the display device 10 in some embodiments is schematically shown.

[0140] In some embodiments, an image source 1 may emit two groups of image light, namely, a first group of image light 111 and a second group of image light 112. The two groups of image light may form two imaging planes through the holographic optical element 2, namely, a first imaging plane 311 and a second imaging plane 312. In some examples, the holographic optical element 2 may image the first group of image light 111 on the first imaging plane 311 and the second group of image light 112 on the second imaging plane 312.

[0141] In some embodiments, the first group of image lights 111 emitted by the image source 1 includes a first red light, a first green light, and a first blue light, the wavelength of the first red light may be 630 nm, the wavelength of the first green light may be 515 nm, and the wavelength of the first blue light may be 445 nm. The second group of image lights 112 emitted by the image source 1 includes a second red light, a second green light, and a second blue light, the wavelength of the second red light may be 643 nm, the wavelength of the second green light may be 532 nm, and the wavelength of the second blue light may be 465 nm. The first group of image lights 111 and the second group of image lights 112 may be displayed in time division.

[0142] Exemplarily, the holographic optical element 2 can be exposed multiple times to form a specific grating structure. For example, based on the imaging optical path of the first imaging plane 311 of the display device 10, the positions and angles of the object light and the reference light of the exposure optical path relative to the holographic optical element 2 can be set, so that the holographic optical element 2 is sequentially exposed to the first red light, the first green light, and the first blue light. Based on the imaging optical path of the second imaging plane 312 of the display device 10, the positions and angles of the object light and the reference light of the exposure optical path relative to the holographic optical element 2 are adjusted, so that the holographic optical element 2 is sequentially exposed to the second red light, the second green light, and the second blue light; thereby forming a grating structure in the holographic optical element 2, and the obtained holographic optical element 2 can image the first group of image lights 111 and the second group of image lights 112 on the first imaging plane 311 and the second imaging plane 312 respectively. Therefore, although the wavelengths of the multi-color lights in a group of image lights are different, the configured holographic optical element 2 can image a group of image lights on one imaging plane, thereby forming a color image; and can form two images on two imaging planes, with good display effects.

[0143] Exemplarily, the first imaging plane 311 and the second imaging plane 312 can be parallel to each other. Correspondingly, the images in the first imaging plane 311 and the second imaging plane 312 can be displayed in parallel.

[0144] Exemplarily, the holographic optical element 2 can be a single-layer thin film. At this time, the thickness of the single-layer thin film is small, it is relatively light and convenient to install. In some other examples, the holographic optical element 2 can be a multi-layer thin film.

[0145] In this embodiment, through the time-division display of two groups of image lights by one image source 1, using the wavelength selectivity of the holographic optical element 2 and combining with the optical path setting of this embodiment, the first group of image lights 111 is imaged on the first imaging plane 311, and the second group of image lights 112 is imaged on the second imaging plane 312, realizing full-color display on two imaging planes, and the structure of the display device 10 is simple and occupies little space.

[0146] Please refer to Figure 9 , Figure 9 is Figure 8 the schematic structural diagram of the display device 10 shown in some other embodiments.

[0147] In some embodiments, the number of image lights emitted by an image source 1 can be three groups, namely a first group of image lights 121, a second group of image lights 122, and a third group of image lights 123. The number of imaging planes formed by the three groups of image lights passing through the holographic optical element 2 is three, namely a first imaging plane 321, a second imaging plane 322, and a third imaging plane 323. In some examples, the first group of image lights 121 can be imaged on the first imaging plane 321, the second group of image lights 122 can be imaged on the second imaging plane 322, and the third group of image lights 123 can be imaged on the third imaging plane 323.

[0148] In some embodiments, the first group of image lights 121 includes a first red light, a first green light, and a first blue light. The wavelength of the first red light can be 620 nm, the wavelength of the first green light can be 510 nm, and the wavelength of the first blue light can be 445 nm. The second group of image lights 122 includes a second red light, a second green light, and a second blue light. The wavelength of the second red light can be 632 nm, the wavelength of the second green light can be 520 nm, and the wavelength of the second blue light can be 455 nm. The third group of image lights 123 can include a third red light, a third green light, and a third blue light. The wavelength of the third red light can be 643 nm, the wavelength of the third green light can be 532 nm, and the wavelength of the third blue light can be 465 nm. Among them, the first group of image lights 121, the second group of image lights 122, and the third group of image lights 123 can be sequentially displayed in time division.

[0149] In some embodiments, the number of thin film layers of the holographic optical element 2 is the same as the number of groups of image lights. For example, the holographic optical element 2 can include three thin films, and the three thin films are stacked on top of each other. The three groups of image lights emitted by the image source 1 are equivalent to including nine lights with different wavelengths. At this time, the nine lights with different wavelengths can be distributed among the three thin films, so that each thin film only diffracts a part of the lights with different wavelengths, so that each thin film has a higher folding rate modulation degree, making the imaging effect of the display device 10 better; and the grating structure prepared for each thin film is also simpler.

[0150] Exemplarily, the multi-layer film includes a first film 21, a second film 22, and a third film 23. Among them, the first film 21 is used to image the first set of image light 121, the second film 22 is used to image the second set of image light 122, and the third film 23 is used to image the third set of image light 123. When preparing the holographic optical element 2, the first film 21 can be exposed first. For example, the first film 21 is exposed in sequence with light having the same wavelength as the first red light, the first green light, and the first blue light; then the second film 22 is exposed. For example, the second film 22 is exposed in sequence with light having the same wavelength as the second red light, the second green light, and the second blue light; finally, the third film 23 is exposed. For example, the third film 23 is exposed in sequence with light having the same wavelength as the third red light, the third green light, and the third blue light. The exposed first film 21, second film 22, and third film 23 are fixedly connected in sequence to form the holographic optical element 2. At this time, the first film 21 of the holographic optical element 2 can image the first set of image light 121 on the first imaging plane 321, the second film 22 of the holographic optical element 2 can image the second set of image light 122 on the second imaging plane 322, and the third film 23 of the holographic optical element 2 can image the third set of image light 123 on the third imaging plane 323.

[0151] Exemplarily, the first imaging plane 321, the second imaging plane 322, and the third imaging plane 323 may be parallel to each other, and this example will not be elaborated here.

[0152] Please refer to Figure 10 , Figure 10 is Figure 6 a schematic structural diagram of the display device 10 in some other embodiments. Among them, Figure 10 the structure of the display device 10 shown in the embodiment includes Figure 8 most of the technical features of the structure of the display device 10 shown in the embodiment. The following mainly describes the differences between the two, and the same technical features of the two will not be elaborated; Figure 10 the display device 10 shown in the embodiment and Figure 8 the main difference of the display device 10 shown in the embodiment lies in the configuration of the holographic optical element 2.

[0153] In some embodiments, the number of image lights emitted by an image source 1 can be 2 groups, namely the first group of image light 131 and the second group of image light 132. The holographic optical element 2 is used to image the first group of image light 131 and the second group of image light 132 on the first imaging plane 331 and the second imaging plane 332 respectively, and there is an included angle between the first imaging plane 331 and the second imaging plane 332.

[0154] Exemplarily, when exposing the holographic optical element 2, the angle and distance between the first imaging plane 331 and the second imaging plane 332 relative to the holographic optical element 2 can be correspondingly adjusted, and the angle and distance between the first position (please refer to Figure 7 ) and the holographic optical element 2 are adjusted accordingly, so that the imaging position of the holographic optical element 2 in the display device 10 is on the first imaging plane 331 and the second imaging plane 332.

[0155] The above embodiments mainly apply the wavelength selection characteristics of the holographic optical element 2. In some embodiments, the holographic optical element 2 of this embodiment can also apply the wavelength selection characteristics and polarization selection characteristics simultaneously. Some embodiments will be described below.

[0156] Please refer to Figure 11 and Figure 12 , Figure 11 is Figure 6 a schematic structural diagram of the display device 10 in some other embodiments, Figure 12 is Figure 6 a schematic structural diagram of the display device 10 in some other embodiments.

[0157] In some embodiments, among the multiple sets of image light emitted by the image source 1, the polarization directions of the same-color light in at least two sets of image light are different.

[0158] Among them, among the multiple sets of image light emitted by the image source 1, when the wavelengths of the same-color light in different sets of image light are different, the wavelengths and polarization directions of the same-color light in several sets of image light are different, and / or, the wavelengths of the same-color light in several sets of image light are the same and the polarization directions are different; at this time, the holographic optical element 2 has wavelength selectivity and polarization selectivity, and when the multiple sets of image light are imaged through the holographic optical element 2, the same-color light with different polarization directions can be imaged on different imaging planes.

[0159] Exemplarily, at this time, photoanisotropic materials such as liquid crystal and liquid crystal polymer can be added to the material of the holographic optical element 2, which is beneficial to enabling the holographic optical element 2 to have polarization selectivity for polarized light.

[0160] Exemplarily, the polarized light can be linearly polarized light. For example, it can be transverse polarized light (X-polarized light) and longitudinal polarized light (Y-polarized light). The polarized light can also be circularly polarized light. For example, it can be left-handed polarized light and right-handed polarized light. This example will not list them one by one.

[0161] Due to the limited bandwidth of the wavelength of a color light and the requirement of a certain difference in the wavelengths of the same-color lights of different groups of image lights, the number of groups of image lights with the same-color lights of different wavelengths is limited. In this embodiment, by making the same-color lights of different groups of image lights have different polarizations and utilizing the wavelength selectivity and polarization selectivity of the holographic optical element 2, the number of groups of image lights breaks through the limitation of the bandwidth of the wavelength of the color light, enabling the image lights to have more groups, so that the image lights can be imaged on more imaging planes, and the display device 10 has more diverse imaging options and a more three-dimensional imaging effect.

[0162] In some embodiments, the number of groups of image lights emitted by the image source 1 is M×N groups. Among them, there are M groups of image lights with the same-color lights of the same polarization direction but different wavelengths, and there are N groups of image lights with the same-color lights of the same wavelength but different polarization directions. At this time, the holographic optical element 2 can have the characteristic of imaging M×N groups of image lights to different imaging planes respectively.

[0163] Exemplarily, please refer to Figure 11 , both M and N can take the value of 2, that is, there are 2 groups of image lights with the same-color lights of different wavelengths, and there are 2 groups of image lights with the same-color lights of the same wavelength but different polarization directions.

[0164] Among them, the image lights emitted by the image source 1 can be 4 groups. For the convenience of description, the four groups of image lights are the first group of image lights 141, that is, (R1, G1, B1)P1, the second group of image lights 142, that is, (R1, G1, B1)P2, the third group of image lights 143, that is, (R2, G2, B2)P1, and the fourth group of image lights 144, that is, (R2, G2, B2)P2, where R represents red light, G represents green light, B represents blue light, and P represents the polarization directions of the three color lights. Among the four groups of image lights, the wavelengths of the color lights in the first group of image lights 141 and the second group of image lights 142 are the same, but the polarization directions are different; the wavelengths of the color lights in the third group of image lights 143 and the fourth group of image lights 144 are the same, but the polarization directions are different. It can be understood that the polarization directions of the multi-color lights in the same group of image lights can be the same, which is convenient for the image source 1 to generate this group of image lights.

[0165] Among them, the imaging planes include the first imaging plane 341, the second imaging plane 342, the third imaging plane 343, and the fourth imaging plane 344. The four groups of image lights are respectively imaged on four imaging planes, that is, the first group of image lights 141 is imaged on the first imaging plane 341 by the holographic optical element 2, the second group of image lights 142 is imaged on the second imaging plane 342 by the holographic optical element 2, the third group of image lights 143 is imaged on the third imaging plane 343 by the holographic optical element 2, and the fourth group of image lights 144 is imaged on the fourth imaging plane 344 by the holographic optical element 2.

[0166] For example, by setting the wavelengths of R1, B1, G1, R2, B2, and G2 correspondingly, the first group of image light 141 is three-color light (630nm, 515nm, 445nm) in the first polarization direction, the second group of image light 142 is three-color light (630nm, 515nm, 445nm) in the first polarization direction, the third group of image light 143 is three-color light (643nm, 532nm, 465nm) in the second polarization direction, and the fourth group of image light 144 is three-color light (643nm, 532nm, 465nm) in the second polarization direction.

[0167] Among them, when preparing the holographic optical element 2, light with the same characteristics as the image light emitted by the image source 1 can be used for exposure, so that the holographic optical element 2 has corresponding imaging characteristics. For example, light with the corresponding wavelength and polarization direction to the first group of image light 141 can be used for exposure. Based on the optical path of the display device 10, three exposures can be performed respectively using R1, G1, and B1 in the first polarization direction; subsequently, light with the corresponding wavelength and polarization direction to the second group of image light 142, the third group of image light 143, and the fourth group of image light 144 can be used for exposure in sequence, and the emission position of the reference light can be adjusted correspondingly according to the corresponding imaging plane. It can be understood that the exposure sequence of light beams with various wavelengths or polarization directions is not strictly limited.

[0168] In this example, by allocating the wavelengths and polarization directions of each color light, and using a combination of color lights with two wavelengths and two polarization directions, 4 kinds of image light can be obtained and can be imaged on 4 imaging planes, which can increase the wavelength difference between the same-color lights of different groups of image light and is beneficial to reducing the interference between different groups of image light.

[0169] Exemplarily, please refer to Figure 12 , M can be a positive integer in the range of 2 to 6, and N can be a positive integer in the range of 2 to 4. For the convenience of explanation, let R represent red light, G represent green light, B represent blue light, and P represent the polarization direction of the three color lights. Multiple groups of image light can be expressed as:

[0170] (R1, G1, B1)P1, (R1, G1, B1)P2, …, (R1, G1, B1)Pn;

[0171] (R2, G2, B2)P1, (R2, G2, B2)P2, …, (R2, G2, B2)Pn;

[0172] …

[0173] (Rm, Gm, Bm)P1, (Rm, Gm, Bm)P1, …, (Rm, Gm, Bm)Pn;

[0174] Exemplarily, when the number of groups of image light is relatively large, the number of thin films of the holographic optical element 2 can be the same as the number of groups of image light, that is, the number of thin films of the holographic optical element 2 is M×N groups. At this time, each layer of thin film can be used to image a group of image light, maximizing the refractive index modulation degree of each layer of thin film, and making the number of thin films reasonable, avoiding the excessive thickness of the holographic optical element 2 caused by too many thin films and the low transmittance of natural light. In some other embodiments, the number of thin films of the holographic optical element 2 is not limited thereto. The maximum number of thin films of the holographic optical element 2 can be the sum of the numbers of color lights in multiple groups of image light. For example, when there are M×N groups of image light and each group of image light has 3 color lights, the maximum number of thin films of the holographic optical element 2 can be M×N×3.

[0175] Among them, there can be M×N imaging planes corresponding thereto. Each group of image light corresponds to an imaging plane. The corresponding relationship between the image light and the imaging plane can refer to Figure 12 the embodiment, and this embodiment will not be elaborated herein.

[0176] In some examples, the virtual images of the M×N groups of image light can cooperate with each other. For example, a three-dimensional stereoscopic image can be formed, and the display device 10 has a more realistic three-dimensional display effect. In other examples, the M×N groups of image light can also display different contents. This embodiment does not strictly limit the display mode of the image light.

[0177] In this example, by reasonably allocating the wavelengths and polarization directions of various color lights, the number of combinations of image light is increased, and it is not restricted by the bandwidth of the color light, so that the display device 10 can display more virtual images, making the number of imaging planes more and denser; when displaying, the display device 10 can display richer contents.

[0178] Please refer to Figure 13 , Figure 13 which Figure 6 is a schematic structural diagram of the display device 10 shown in another embodiment.

[0179] In some embodiments, at least two groups of image light among multiple groups of image light are reflected by the holographic optical element 2 to different eye box 4 positions for being observed and imaged at different eye box 4 positions. At this time, based on the wavelength selectivity and angle selectivity of the holographic optical element 2, at least two groups of image light are reflected to different eye box 4 positions. Different observers (such as drivers and passengers) can respectively observe at different eye box 4 positions, so as to respectively receive different image lights, and the different image lights are respectively imaged, realizing the virtual reality images provided for different observers by one image source 1 respectively and meeting the different needs of different observers.

[0180] Among them, since different image lights are reflected by the holographic optical element 2 to different positions of the eye box 4, an observer can observe only at one position of the eye box 4 and can only observe the image light at the position of the eye box 4 where he is located. The observed image light can form a virtual image on the imaging plane 3, thereby forming a virtual reality image. It can be understood that the images observed by different eye boxes 4 depend on the corresponding image lights. Therefore, by controlling the display content of different groups of image lights, different observers can observe the same or different virtual reality images, so that a set of display devices 10 can meet the needs of multiple people, and the volume of a set of display devices 10 is small and the applicable range is wide.

[0181] Among them, different eye boxes 4 can be distributed at different positions in the horizontal direction. Different eye boxes 4 can have the same height in the vertical direction or can be at different heights, so that different people can observe the virtual reality image from different positions of the eye box 4, so that each observer has a strong sense of immersion. The position of the eye box 4 can be set according to needs, and this embodiment does not make strict limitations on this.

[0182] Among them, the imaging plane 3 corresponding to one eye box 4 can be one or more, and this embodiment does not make strict limitations on this. When the imaging plane 3 corresponding to one eye box 4 is multiple, the setting of the image light can refer to the relevant scheme shown in the previous text Figures 8 to 12 and will not be elaborated in this embodiment.

[0183] It can be understood that the position of the eye box 4 can be realized by configuring the holographic optical element 2. Exemplarily, when exposing the holographic optical element 2, based on the imaging optical path of the display device 10, the horizontal angle of the object light exit position relative to the holographic optical element 2 can be adjusted to set the position of the eye box 4 and synchronously set the position of the corresponding imaging plane 3.

[0184] Please refer to Figure 14 , Figure 14 which Figure 13 is a schematic structural diagram of the display device 10 in some embodiments. Among them, Figure 14 the shown display device 10 is Figure 13 a schematic structural diagram of the display device 10 in a top view angle.

[0185] In some embodiments, the number of eye boxes may be two, namely the first eye box 411 and the second eye box 412. Exemplarily, the number of image lights emitted by an image source 1 may be two groups, namely the first group of image lights 151 and the second group of image lights 152. The number of imaging planes formed by the two groups of image lights passing through the holographic optical element 2 is two, namely the first imaging plane 351 and the second imaging plane 352. Among them, the holographic optical element 2 can reflect the first group of image lights 151 to the first eye box 411 and form an image on the first imaging plane 351, and the holographic optical element 2 can reflect the second group of image lights 152 to the second eye box 412 and form an image on the second imaging plane 352.

[0186] Among them, the first eye box 411 and the second eye box 412 may be arranged in the horizontal direction. Exemplarily, the first eye box 411 may be located at the driving position so that the driver can observe the virtual reality image; the second eye box 412 may be located at the co-pilot position so that the passengers in the co-pilot can observe the virtual reality image. In some examples, the first eye box 411 and the second eye box 412 may be substantially symmetrically distributed relative to the display device 10, and the first imaging plane 351 and the second imaging plane 352 are also substantially symmetrically distributed in the horizontal direction, enabling both the driver and the passengers to conveniently observe the virtual reality image and providing a good sense of immersion for both the driver and the passengers.

[0187] It can be understood that the positions of the first eye box 411 and the second eye box 412 can be achieved by configuring the holographic optical element 2. Exemplarily, when exposing the holographic optical element 2, based on the imaging optical path of the display device 10, the horizontal angle of the object light relative to the holographic optical element 2 can be adjusted to set the positions of the first eye box 411 and the second eye box 412. At this time, the first imaging plane 351 and the second imaging plane 352 can be correspondingly configured.

[0188] In some embodiments, the display schemes of the first group of image lights 151 and the second group of image lights 152 of the image source 1 can refer to the display scheme of the image source 1 in the previous Figure 8 embodiment, and this embodiment will not elaborate on it here.

[0189] Please refer to Figure 15 , Figure 15 which Figure 14 is another schematic diagram of the structure of the display device 10 shown. Figure 15 The structure of the display device 10 shown includes Figure 14 most of the technical features of the structure of the display device 10 shown in the embodiment. The following mainly describes the differences between the two, and the same technical features of the two will not be elaborated; Figure 15 The display device 10 shown in the embodiment and Figure 14The main difference of the display device 10 shown in the embodiment lies in the configuration of the eyebox position.

[0190] In some embodiments, the first eyebox 411 and the second eyebox 412 can be arranged in the horizontal direction, with the first eyebox 411 and the corresponding imaging plane as the main, so that better imaging effects can be obtained when observing from the first eyebox 411.

[0191] Among them, the first eyebox 411 can be approximately in the same vertical plane as the holographic optical element 2, and the first imaging plane 351 can also correspondingly be in the same vertical plane as the first eyebox 411 and the holographic optical element 2.

[0192] Exemplarily, the vertical plane where the first eyebox 411 and the holographic optical element 2 are located can be perpendicular or approximately perpendicular to the holographic optical element 2. At this time, the first eyebox 411 can be located at the driver's position, the main position of the holographic optical element 2 can be in front of the driver, the image light emitted by the image source 1 is mainly directed towards the holographic optical element 2 in front of the driver, and the first imaging plane 351 can be located directly in front of the vehicle. The driver can observe the virtual reality image without turning his head or eyes.

[0193] In addition, the second eyebox 412 and the holographic optical element 2 can also be in the same vertical plane. The second eyebox 412 is located at the co-driver's position, but the holographic optical element 2 in front of the driver is relatively in the obliquely front of the co-driver. Therefore, the image light enters the second eyebox 412 from the obliquely front of the second eyebox 412, and the virtual reality image is also imaged on the second imaging plane 352 in the obliquely front of the driver. At this time, the passengers at the co-driver's position can also observe the virtual reality image at the co-driver's position.

[0194] Please refer to Figure 16 , Figure 16 is Figure 13 the schematic structural diagram of the display device 10 in some other embodiments. Among them, Figure 16 the shown display device 10 is relative to Figure 13 the schematic structural diagram of the display device 10 shown in the top view.

[0195] In some embodiments, the number of eyeboxes can be three, namely the first eyebox 421, the second eyebox 422, and the third eyebox 423.

[0196] Exemplarily, the number of image lights emitted by an image source 1 can be three groups, namely the first group of image lights 161, the second group of image lights 162, and the third group of image lights 163. The number of imaging planes formed by the three groups of image lights passing through the holographic optical element 2 is three, namely the first imaging plane 361, the second imaging plane 362, and the third imaging plane 363. Among them, the holographic optical element 2 can reflect the first group of image lights 161 to the first eye box 421 and form an image on the first imaging plane 361. The holographic optical element 2 can reflect the second group of image lights 162 to the second eye box 422 and form an image on the second imaging plane 362. The holographic optical element 2 can reflect the third group of image lights 163 to the third eye box 423 and form an image on the third imaging plane 363.

[0197] Among them, the installation positions of the image source 1 and the holographic optical element 2 can refer to Figure 14 the relevant solutions in the embodiments. Moreover, the first eye box 421, the second eye box 422, and the corresponding first group of image lights 161, the second group of image lights 162 can also refer to Figure 14 the relevant solutions in the embodiments. This embodiment will not be elaborated herein.

[0198] Among them, the third eye box 423 can be located between the first eye box 421 and the second eye box 422. The third imaging plane 363 is located between the first imaging plane 361 and the second imaging plane 362. Moreover, the third eye box 423 can be relatively farther from the holographic optical element 2 than the first eye box 421 and the second eye box 422, so that the third eye box 423 can be located at the rear row of the vehicle. At this time, the passengers sitting in the rear row of the vehicle can also observe the virtual reality image on the third imaging plane 363 at the position of the third eye box 423, and the user experience is better.

[0199] It should be noted that, without conflict, the embodiments and the features in the embodiments in the present application can be combined with each other. Any arbitrary combination of the features in different embodiments is also within the protection scope of the present application. That is to say, the above-described multiple embodiments can also be arbitrarily combined according to actual needs.

[0200] It should be noted that all the above-mentioned drawings are exemplary illustrations of the present application and do not represent the actual size of the product. Moreover, the dimensional proportional relationship between the components in the drawings is not used as a limitation to the actual product of the present application.

[0201] The above are only some embodiments and implementation manners of the present application. The protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A display device, characterized in that, Comprising a holographic optical element and an image source; The image source is located on one side of the holographic optical element, and the image source is configured to generate multiple sets of image light for alternate display; at least two sets of the multiple sets of image light include multicolor light, and the wavelengths of the same-color light in different sets of image light are different; The holographic optical element is configured to receive the multiple sets of image light, and the holographic optical element is configured to respectively form virtual images of the multiple sets of image light on different imaging planes, and the imaging planes are located on the other side of the holographic optical element.

2. The display device according to claim 1, characterized in that, The multicolor light includes at least two of red light, green light, and blue light.

3. The display device according to claim 2, wherein The multiple sets of image light have the same exit position and exit angle at the image source.

4. The display device according to claim 3, wherein, The wavelength difference of the same-color light in the multiple sets of image light is greater than or equal to 5 nm.

5. The display device according to any one of claims 1 to 4, characterized in that, The display frequency of each set of image light is greater than or equal to 25 Hz.

6. The display device according to any one of claims 1 to 5, characterized in that The multiple sets of image light are respectively imaged on the multiple imaging planes in one-to-one correspondence; The multiple imaging planes are arranged in parallel; or, there is an included angle between at least two of the multiple imaging planes.

7. The display device according to any one of claims 1 to 6, characterized in that, The polarization directions of the same-color light in at least two sets of the multiple sets of image light are different.

8. The display device according to any one of claims 1 to 6, characterized in that, The number of the image light is in the range of 2 to 10; Alternatively, the holographic optical element has wavelength selection characteristics and polarization selection characteristics, the number of the image light is M×N sets, among the M×N sets of image light, there are M sets of image light with the same-color light of the same polarization direction and different wavelengths, and there are N sets of image light with the same-color light of the same wavelength and different polarization directions, M is a positive integer in the range of 2 to 10, and N is a positive integer in the range of 2 to 4.

9. The display device according to any one of claims 1 to 8, characterized in that, The holographic optical element includes X layers of thin films, and the X layers of thin films are stacked, and the number of layers of the thin films is related to the number of sets of the image light, and X is a positive integer.

10. The display device according to claim 9, wherein The image light generated by the image source includes Y sets of image light, the holographic optical element includes Y layers of thin films, and one layer of thin film is used to image a set of corresponding image light, and Y is a positive integer in the range of 2 to 10.

11. The display device according to any one of claims 1 to 10, characterized in that, At least two sets of the multiple sets of image light are reflected by the holographic optical element to different eyebox positions for being observed and imaged at different eyebox positions.

12. The display device according to any one of claims 1 to 11, characterized in that, The material of the holographic optical element includes one or more of silver salt dry plate, photopolymer, dichromated gelatin, photorefractive material, photochromic material, photoanisotropic material, etchant, liquid crystal, liquid crystal polymer, and metasurface.

13. A cockpit system, characterized in that, Comprising an intelligent driving module and a display device according to any one of claims 1-12, the image source of the display device is electrically connected to the intelligent driving module, and the intelligent driving module is configured to control the display content of the image source.

14. A vehicle, characterized in that, Comprising: A housing; A windshield, mounted on the housing; And A display device according to any one of claims 1 to 12, the image source of the display device is mounted inside the housing, and the holographic optical element of the display device is mounted on the windshield.

15. A vehicle according to claim 14, characterized in that, The holographic optical element is fixed on the side of the windshield facing the inside of the housing; or, the holographic optical element is embedded inside the windshield.

16. A wearable device, characterized in that, Comprising: A frame; Lenses, mounted on the frame; And The display device according to any one of claims 1 to 12, wherein an image source of the display device is installed inside the spectacle frame, and a holographic optical element of the display device is installed on the spectacle lens.

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