WO2022052111A1

WO2022052111A1 - Head-up display device, head-up display method and vehicle

Info

Publication number: WO2022052111A1
Application number: PCT/CN2020/115103
Authority: WO
Inventors: 周鹏程; 张宇腾; 于海
Original assignee: 华为技术有限公司
Priority date: 2020-09-14
Filing date: 2020-09-14
Publication date: 2022-03-17
Also published as: CN112673300A

Abstract

A head-up display device (400) and a head-up display method, applied to the fields of automotive, aviation, aerospace, navigation and the like. The head-up display device (400) comprises a variable-focus holographic optical element (HOE) lens (410) and a picture projection device (420). The HOE lens (410) is attached to the light-transmitting plane, and the working time sequence of the HOE lens (410) comprises N time periods, and the HOE lens (410) corresponds to different focal lengths and different deflection angles in the N time periods, respectively. The picture projection device (420) comprises a picture generation unit (PGU) (421) and an optical lens group (422). The PGU (421) is used for generating N projection pictures corresponding to N time periods, the optical lens group (422) is used for projecting the N projection pictures to the HOE lens (410), and by means of reflection of the HOE lens (410), virtual pictures of the N projection pictures are focused to different depths outside the light-transmitting plane. On the basis of the PGU (421) and the variable-focus HOE lens (410), double-screen or even multi-screen display can be realized, and the size and cost of the picture projection device (420) in the head-up display device (400) are effectively reduced.

Description

Head-up display device, head-up display method, and vehicle

technical field

The present application relates to the field of smart vehicles, and in particular, to a head-up display device, a head-up display method, and a vehicle.

Background technique

Head-up display (HUD) technology, also known as head-up display technology, has been gradually applied in the automotive field, aerospace field and navigation field in recent years. For example, in the field of automobiles, the image projection device in the HUD device projects important information during the driving of the car onto the windshield. After the reflection of the windshield, a virtual image is formed directly in front of the driver's line of sight, so that the driver does not need to bow his head. see this information. Compared with the display methods such as the instrument panel and the central control screen that require the driver to look down, the HUD avoids the driving risk that the driver cannot take into account the road conditions when looking down, and is a safer vehicle display method.

At present, the traditional HUD mainly displays vehicle instrument information such as vehicle speed and fuel volume. In order not to interfere with road conditions, the imaging distance is about 2 to 3 meters. Augmented reality (AR) HUD (AR-HUD) that has emerged in recent years superimposes digital images on the real environment outside the car, enabling drivers to obtain augmented reality visual effects, which can be used for AR navigation, adaptive cruise, lane departure Warning, etc. In order to better integrate AR images with road information, the imaging distance of AR-HUD is generally about 7 to 15 meters.

Since AR-HUD and traditional HUD imaging distances are not consistent, in order to display instrument information such as vehicle speed and AR images at the same time, images of two focal planes need to be generated. The current mainstream solution is dual-screen display. The specific implementation method is to use two sets of image generation units (PGUs) in the image projection device to generate AR images and instrument information respectively, and then convert the virtual image of the AR image and instrument information. The virtual image is projected to two focal planes outside the windshield to realize traditional HUD and AR-HUD display, as shown in Figure 1. However, two sets of PGUs are used to realize dual-screen display, which increases the volume and cost of the image projection device in the HUD device.

SUMMARY OF THE INVENTION

The present application provides a head-up display device, a head-up display method and a vehicle, which can be used to reduce the volume and cost of an image projection device in a HUD device.

In a first aspect, a head-up display device is provided, comprising: a zoomable holographic optical element HOE lens and an image projection device; the HOE lens is attached to a light-transmitting plane, the working sequence of the HOE lens includes N time periods, the The HOE lens corresponds to different focal lengths and different deflection angles respectively in the N time periods, where N is a positive integer greater than or equal to 2; the image projection device includes an image generation module PGU and an optical lens group, the PGU is used to generate a pair of There should be N projection images of N time periods, the optical lens group is used to project the N projection images to the HOE lens, and through the reflection of the HOE lens, the virtual images of the N projection images are focused outside the light transmission plane at different depths.

It should be understood that the PGU generates N projection images corresponding to N time periods, in other words, the PGU generates one image at a time, by alternately generating N projection images corresponding to N time periods.

The head-up display device of the embodiment of the present application includes a HOE lens and an image projection device. The working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, and the image projection device includes a PGU, which is used to generate N projection images corresponding to the N time periods . When the N projection images are projected to the HOE lens in N time periods respectively, they are subject to different degrees of focusing and deflection, so that the virtual images corresponding to the N projection images can be presented at different depths outside the light transmission plane, realizing the N screen ( N≥2) display. That is to say, the present application can realize dual-screen or even multi-screen display based on one PGU and HOE lens, which effectively reduces the volume and cost of the image projection device in the HUD device.

In combination with the first aspect, in some implementations of the first aspect, the HOE lens includes M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state, By separately controlling the film state of each HOE film, the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods.

Optionally, a voltage can be applied to each HOE film, and the film state of each HOE film can be switched by controlling the on and off of the voltage.

In combination with the first aspect, in some implementations of the first aspect, if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle; if the film state of the HOE film is a diffraction state , the HOE film has a focusing function and has a deflection angle.

It should be understood that if the film state of the HOE film is a transparent state, the HOE film has no focusing function and no deflection angle, which means that in the transparent state, the focal length and deflection angle of the HOE film are both 0. If the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle, which means that in the diffractive state, the focal length and deflection angle of the HOE film are not zero.

With reference to the first aspect, in some implementations of the first aspect, each of the M-layers of HOE films has different focal lengths and different deflection angles when in a diffractive state.

In other words, when each layer in the M-layer HOE film is in a diffractive state, each layer has different focusing ability and deflection degree for incident light.

In combination with the first aspect, in some implementations of the first aspect, the deflection angle of the HOE film in the diffractive state is 2° to 15°, and the deflection angle of the HOE lens is all of the M-layer HOE film in the diffractive state. The sum of the deflection angles of the HOE films.

With reference to the first aspect, in some implementations of the first aspect, the relationship between M and N is: N=2 ^M .

In conjunction with the first aspect, in certain implementations of the first aspect, the HOE film is prepared from polymer dispersed liquid crystal PDLC.

It should be understood that the polymer dispersed liquid crystal PDLC can exhibit different states under the control of voltage. That is, a voltage is applied to the HOE film, and the film state of the HOE film can be switched by controlling the on and off of the voltage.

In combination with the first aspect, in some implementations of the first aspect, the HOE thin film is prepared by any one of an exposure method, an electron beam lithography method, or a nanoimprint method.

In combination with the first aspect, in some implementations of the first aspect, the HOE lens is prepared as follows: a parallel laser beam and a focused laser beam with a deflection angle are used to interfere with each other on a polymer dispersed liquid crystal (PDLC) holographic dry plate The HOE film is obtained; the HOE lens is obtained by stacking M layers of the HOE film, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles respectively.

With reference to the first aspect, in some implementations of the first aspect, the apparatus further includes: a controller, configured to control the PGU to generate N projection images corresponding to the N time periods; and/or, to control The film state of each HOE film makes the HOE lens correspond to different focal lengths and different deflection angles respectively in the N time periods.

With reference to the first aspect, in some implementations of the first aspect, a unit time includes K working cycles, each working cycle includes N time periods, and K is greater than or equal to a preset threshold.

In the embodiment of the present application, by controlling the switching frequency of the N time periods, virtual images of N projection images can be simultaneously presented at different depths outside the light-transmitting plane by utilizing the human eye persistence effect.

Optionally, the switching frequency of the N periods can be controlled by the voltage frequency. That is, it can be controlled by controlling the frequency at which the voltage is turned on and off.

With reference to the first aspect, in some implementations of the first aspect, the N projection images include: a first projection image and a second projection image, the first projection image is used to display instrument information, and the second projection image is used for displaying instrument information. for displaying augmented reality image information.

It should be understood that, in the embodiment of the present application, by controlling the focal length and deflection angle of the HOE lens in the time period corresponding to the first projection image and the second projection image, different image contents can be displayed at different depths, that is, different image contents can be displayed at different depths from 2 to 2. Display instrument information at a distance of 3 meters, and display augmented reality image information at a distance of 7 to 15 meters, enabling dual-screen display.

With reference to the first aspect, in some implementations of the first aspect, the optical mirror group includes: a flat mirror and a curved mirror, the flat mirror and the curved mirror are located between the HOE lens and the PGU, the N projected images are reflected to the HOE lens via the flat mirror and the curved mirror.

In a second aspect, a head-up display method is provided, the head-up display method is implemented in a head-up display device, and the head-up display device includes: a variable-focus holographic optical element HOE lens and an image projection device; the HOE lens is attached to a light-transmitting device. On a plane, the working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, wherein N is a positive integer greater than or equal to 2; the image projection device includes a an image generation module PGU and an optical lens group, the PGU is used to generate N projection images corresponding to the N time periods; the head-up display method includes: projecting the N projection images to the HOE lens through the optical lens group, and passing the N projection images to the HOE lens through the optical lens group The reflection of the HOE lens causes the virtual images of the N projected images to be focused at different depths outside the light transmission plane.

In conjunction with the second aspect, in some implementations of the second aspect, the HOE lens includes M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state, By separately controlling the film state of each HOE film, the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods.

In combination with the second aspect, in some implementations of the second aspect, if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle; if the film state of the HOE film is a diffraction state , the HOE film has a focusing function and has a deflection angle.

With reference to the second aspect, in some implementations of the second aspect, each of the M layers of HOE films has different focal lengths and different deflection angles when in a diffractive state.

In combination with the second aspect, in some implementations of the second aspect, the deflection angle of the HOE film in the diffractive state is 2° to 15°, and the deflection angle of the HOE lens is the deflection angle of the M-layer HOE film in the diffractive state. Sum of deflection angles of all HOE films.

With reference to the second aspect, in some implementations of the second aspect, the relationship between M and N is: N=2 ^M .

In combination with the second aspect, in some implementations of the second aspect, the HOE thin film is prepared by any one of an exposure method, an electron beam lithography method, or a nanoimprint method.

In combination with the second aspect, in some implementations of the second aspect, the HOE lens is prepared as follows: using a parallel laser beam and a focused laser beam with a deflection angle to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate The HOE film is obtained; the HOE lens is obtained by stacking M layers of the HOE film, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles respectively.

With reference to the second aspect, in some implementations of the second aspect, a unit time includes K working cycles, each working cycle includes the N time periods, and K is greater than or equal to a preset threshold.

With reference to the second aspect, in some implementations of the second aspect, the N projection images include: a first projection image and a second projection image, the first projection image is used to display instrument information, and the second projection image is used for displaying instrument information. for displaying augmented reality image information.

With reference to the second aspect, in some implementations of the second aspect, the optical mirror group includes: a flat mirror and a curved mirror, the flat mirror and the curved mirror are located between the HOE lens and the PGU, the N projected images are reflected to the HOE lens via the flat mirror and the curved mirror.

In a third aspect, a method for preparing a holographic optical element HOE lens is provided. The working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, wherein N is A positive integer greater than or equal to 2; the HOE lens includes M layers of variable-focus HOE films, where M is a positive integer; the preparation method of the HOE lens is as follows: a beam of parallel laser and a beam of focused laser with a deflection angle are used in the polymer The HOE film is obtained by interfering with each other on the dispersed liquid crystal PDLC holographic dry plate; the HOE lens is obtained by stacking M layers of the HOE film, wherein each layer of the M layers is prepared by focusing lasers with different focal lengths and different deflection angles.

In combination with the third aspect, in some implementations of the third aspect, the HOE film has at least two film states, and the film state includes a transparent state and a diffractive state. The lenses correspond to different focal lengths and different deflection angles respectively in the N time periods.

In combination with the third aspect, in some implementations of the third aspect, if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle; if the film state of the HOE film is a diffraction state , the HOE film has a focusing function and has a deflection angle.

With reference to the third aspect, in some implementations of the third aspect, the deflection angle of the HOE film in the diffractive state is 2° to 15°, and the deflection angle of the HOE lens is that the M-layer HOE film is in the diffractive state. The sum of the deflection angles of all HOE films.

With reference to the third aspect, in some implementations of the third aspect, the relationship between M and N is: N=2 ^M .

In a fourth aspect, a vehicle is provided, including the device in the first aspect or any possible implementation manner of the first aspect.

In a fifth aspect, an in-vehicle system is provided, including the device in the first aspect or any possible implementation manner of the first aspect.

A sixth aspect provides a method for controlling a HOE lens, the HOE lens comprising M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffraction state, the method The method includes: controlling the film state of each HOE film respectively, so that the HOE lens corresponds to different focal lengths and different deflection angles respectively in the N time periods.

A seventh aspect provides a controller, the controller includes an input/output interface, a processor and a memory, the processor is used to control the input/output interface to send and receive signals or information, the memory is used to store a computer program, the processor is used to control the The computer program is invoked and executed in the memory to cause the controller to perform the methods of the above-described aspects.

An eighth aspect provides a computer program product comprising instructions that, when the computer program product is run on a computer, causes the computer to execute the method in the second aspect or any implementation of the second aspect, and/or execute the above The third aspect or the method in any implementation manner of the third aspect, and/or perform the method in the sixth aspect or any implementation manner of the sixth aspect.

In a ninth aspect, a computer-readable storage medium is provided, where the computer-readable medium stores program codes for device execution, the program codes including the second aspect or any possible implementation manner of the second aspect. The instruction of the method in, and/or the instruction of executing the method in the above third aspect or any implementation of the third aspect, and/or the execution of the method in the above sixth aspect or any implementation of the sixth aspect. instruction.

A tenth aspect provides a chip, the chip includes a processor and a data interface, the processor reads an instruction stored in a memory through the data interface, and executes the second aspect or any possible implementation of the second aspect and/or perform the method in the above third aspect or any implementation manner of the third aspect, and/or perform the method in the above sixth aspect or any implementation manner of the sixth aspect.

Optionally, as an implementation manner, the chip may further include a memory, in which instructions are stored, the processor is configured to execute the instructions stored in the memory, and when the instructions are executed, the The processor is configured to execute the method in the second aspect or any possible implementation manner of the second aspect, and/or execute the method in the above-mentioned third aspect or any implementation manner of the third aspect, and/or execute the above-mentioned sixth aspect Aspects or instructions of the method in any implementation of the sixth aspect.

Description of drawings

1 is an example diagram of a head-up display scene provided by an embodiment of the present application;

Fig. 2 is a plane example diagram of a head-up display scene provided by an embodiment of the present application;

FIG. 3 is an example diagram of an existing head-up display device provided by an embodiment of the present application;

4 is an example diagram of an application scenario of a head-up display provided by an embodiment of the present application;

FIG. 5 is an example diagram of a head-up display device provided by an embodiment of the present application;

6 is an exemplary diagram of a state switching of a PDLC material provided by an embodiment of the present application;

7 is a structural example diagram of a dual-screen head-up display device provided by an embodiment of the present application;

8 is a structural example diagram of another dual-screen head-up display device provided by an embodiment of the present application;

9 is a structural example diagram of a four-screen head-up display device provided by an embodiment of the present application;

FIG. 10 is an example diagram of a preparation method of a HOE lens provided in an embodiment of the present application;

11 is an example diagram of preparing a variable focus HOE film by an exposure method provided in the embodiment of the present application;

FIG. 12 is an example diagram of a head-up display method provided by an embodiment of the present application.

detailed description

The technical solutions in the present application will be described below with reference to the accompanying drawings.

Head-up display (HUD) technology, also known as head-up display technology, has been gradually applied in the automotive field, aerospace field and navigation field in recent years. For example, it can be applied to vehicles, and can also be applied to other vehicles such as airplanes, aerospace vehicles, and ships. For convenience of description, in this application, the vehicle-mounted HUD is used as an example for description. However, it should be understood that this should not be taken as a limitation of the present application.

At present, the traditional vehicle HUD mainly displays vehicle instrument information such as vehicle speed and fuel volume. In order not to interfere with road conditions, the imaging distance is about 2 to 3 meters. Augmented reality (AR) HUD (AR-HUD), which has emerged in recent years, superimposes digital images on the real environment outside the car, enabling drivers to obtain augmented reality visual effects, which can be used for AR navigation, adaptive cruise, and lane departure. Warning and other scenarios. In order to better integrate AR images with road information, the imaging distance of AR-HUD is generally about 7 to 15 meters. It can be seen that the imaging distance between AR-HUD and traditional HUD is not consistent. In order to display instrument information such as vehicle speed and AR images at the same time, images of two focal planes need to be generated. And in order to improve the driver's experience and driving safety, it is usually required that the images of the two focal planes (dual screens) do not overlap each other and do not interfere with each other. It should be understood that the "screen" referred to in this application is a focal plane, which represents the imaging position of a virtual image, rather than a screen in the actual sense.

FIG. 2 is a schematic plan view of a head-up display scene provided by an embodiment of the present application. As shown in Figure 2, the image projection device in the vehicle-mounted HUD device can be installed near the windshield. The image projection device can image the projected object A and object B at different depths outside the windshield by using the windshield or the glass, mirrors and other light-transmitting planes near the windshield, so that the driver does not lower his head. , You can see the driving information without turning your head. Among them, object A can display vehicle instrument information such as vehicle speed and fuel level. Object B can display AR image information, superimposing the digital image on the real environment outside the car.

The existing solution adopts two sets of picture generation units (PGU) in the image projection device to realize the traditional HUD and AR-HUD respectively on the two focal planes at the same time. As shown in Figure 3, the two sets of PGUs share the curved mirror optical system at the rear end. Due to the different distances from the curved mirror, the positions of the virtual images formed through the windshield are also different, forming two different depths of screen A and screen B. Image display. So that the closer A screen can display instrument information, and the far B screen can display AR image information.

However, two sets of PGUs are used to realize dual-screen display, which increases the volume and cost of the image projection device in the HUD device.

In view of the above problems, the present application provides a head-up display device, which is mainly based on a PGU and a zoomable holographic optical element (HOE) lens to realize dual-screen or even multi-screen display, effectively reducing the cost of the image projection device and volume.

Among them, the variable focus HOE lens is composed of a polymer film, which can be used as a diffractive optical element and can be attached to the windshield. It can reflect the image light generated by the PGU in the image projection device, and by controlling the focal length of the HOE lens, the virtual image of the image can be focused to different depths outside the vehicle. Therefore, the use of two sets of PGUs in the image projection device is effectively avoided, and the distances between the two sets of PGUs and the curved mirror are controlled to realize imaging at different depths, thereby effectively reducing the cost and volume of the image projection device.

In order to better understand the solution of the embodiment of the present application, before describing the device of the embodiment of the present application, an application scenario of the embodiment of the present application is briefly described first with reference to FIG. 4 .

FIG. 4 is an example diagram of an application scenario of a head-up display provided by an embodiment of the present application.

As shown in FIG. 4 , an application scenario provided by the present application is a vehicle-mounted HUD. When the driver drives the vehicle, the image projection device in the vehicle (usually placed in the console under the windshield of the vehicle) projects an image, and passes through the The reflection of the HOE lens attached to the windshield makes the virtual image corresponding to the image area focus to different depths outside the vehicle. The closer virtual image screen can display instrument information, and the imaging distance is about 2 to 3 meters; the farther virtual image screen displays AR navigation, AR early warning and other information, and the imaging distance is about 7 to 15 meters.

The head-up display device provided by the present application will be described in detail below with reference to the accompanying drawings. FIG. 5 is an example diagram of a head-up display device provided by an embodiment of the present application. As shown in FIG. 5 , the head-up display device 400 includes a HOE lens 410 and an image projection device 420 .

The HOE lens 410 is attached to the light-transmitting plane, the working sequence of the HOE lens 410 includes N time periods, and the HOE lens 410 corresponds to different focal lengths and different deflection angles in the N time periods, wherein N is greater than or equal to 2 positive integer.

The image projection device 420 includes an image generation module PGU421 and an optical lens group 422 . The PGU 421 is used to generate N projection images corresponding to N time periods, and the optical lens group 422 is used to project the N projection images to the HOE lens 410, and after the reflection of the HOE lens 410, the virtual images of the N projection images are focused on the light-transmitting plane at different depths outside.

It should be understood that the HOE lens 410 of the present application is a variable focus lens, and its focal length and deflection angle will vary with the time period. At the same time, the PGU alternately generates different projection images corresponding to different time periods. That is to say, any image generated by the PGU corresponds to a focal length and a deflection angle, thereby realizing the presentation of different images at different depths and positions outside the vehicle.

It should be understood that in practical applications, if it is only required that the virtual images do not overlap and the imaging depth is not required, then the HOE lens 410 may only be required to correspond to different deflection angles in N time periods. The specific operation mode should be determined according to the actual situation, which is not limited in this application.

It should be understood that this application does not limit the length of each of the N time periods, which means that the lengths of the N time periods can be the same or different, which means that the PGU alternately generates the N projection images when each image is displayed. Lengths can vary. It should be understood that, in the following specific implementation manner, for the convenience of description, the same N time periods are used as examples.

It should be understood that different deflection angles may refer to deflection angles of different magnitudes, and may also refer to deflection angles of different magnitudes and different deflection directions. Therefore, by controlling the focal length, deflection angle and deflection direction of the HOE lens at each time period in the N time periods, the virtual images of the N projected images can be arranged up and down at different depths outside the light transmission plane, or left and right. arranged, or otherwise arranged. At the same time, it can also be ensured that the virtual images corresponding to the N projection images do not overlap each other and do not interfere with each other.

Optionally, the unit time includes K working cycles, each working cycle includes N time periods, and K is greater than or equal to a preset threshold.

In the embodiment of the present application, by controlling the switching frequency of the N time periods, virtual images of N projection images can be simultaneously presented at different depths outside the light-transmitting plane by utilizing the human eye persistence effect. Exemplarily, if N=2, the switching frequencies of the two time periods and the two projection images can be controlled to be 24 Hz, or 36 Hz, 48 Hz, or 72 Hz. In general, when the switching frequency of the image is greater than or equal to 24HZ, a coherent image can be seen due to the persistence effect of the human eye. Therefore, at this time, two virtual images of the projected images can be simultaneously presented at different depths outside the light-transmitting plane. It should be understood that, in practical applications, the switching frequency may be set according to actual requirements, which is not limited in this application.

Optionally, the HOE lens includes M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state. The N time periods correspond to different focal lengths and different deflection angles respectively.

It should be understood that if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle; if the film state of the HOE film is a diffraction state, the HOE film has a focusing function and has a deflection angle. In other words, if the film state of the HOE film is a transparent state, the focal length and deflection angle of the HOE film are both zero. If the film state of the HOE film is a diffractive state, neither the focal length nor the deflection angle of the HOE film is zero. It means that by controlling the film state of each HOE film, the HOE lens can have different deflection and focusing abilities.

Alternatively, the deflection angle of the HOE film in the diffractive state may range from 2° to 15°.

Optionally, the deflection angle of the HOE lens is the sum of deflection angles of all the HOE films in the diffractive state in the M-layer HOE films.

Optionally, each HOE film in the M layers of HOE films may have different focal lengths and different deflection angles respectively when in the diffractive state. In other words, when each layer in the M-layer HOE film is in a diffractive state, each layer has different focusing ability and deflection degree for incident light.

At this time, the relationship between M and N may be: N=2 ^M . Exemplarily, if the HOE lens includes a layer of HOE film, two working states can be achieved, one is a transparent state and the other is a diffractive state, and these two working states can be performed in two time periods; for example, if the HOE The lens includes two layers of HOE films, each of which has two film states, and the focal lengths and deflection angles of the two films in the diffractive state are different, then four working states can be realized according to the arrangement and combination, and these four working states can be in four periods. When there are more layers, the above method can also be used, and details are not described here.

Optionally, each HOE film in the M layers of HOE films may also have the same focal length and deflection angle when in a diffractive state. At this time, N and M no longer satisfy the above relationship. Exemplarily, if the HOE lens includes two layers of HOE films, each of which has two film states, and the focal lengths and deflection angles of the two films in the diffractive state are the same, then three working states are included: a It is to control both layers to be in a transparent state; one is to control any one of the layers to be in a transparent state and the other to be in a diffractive state; the other is to control both layers to be in a diffractive state, and these three working states can be in three time periods. , which presents different images at three depths.

Optionally, each HOE thin film in the M layers of HOE thin films may partially have different focal lengths and deflection angles when in a diffractive state. This application does not limit this, and for the convenience of description, it is considered hereinafter that each HOE film in the M layers of HOE films has different focal lengths and different deflection angles respectively when in the diffraction state. And in the following specific embodiments, one layer and two layers will be used as examples to expand the description.

Optionally, the above head-up display device 400 may further include: a controller. The controller can be used to control the PGU to generate N projection images corresponding to the N time periods; and/or, be used to control the film state of the HOE film of each layer, so that the HOE lens corresponds to different focal lengths respectively in the N time periods and different deflection angles. Alternatively, the HOE film can be prepared from polymer dispersed liquid crystal (PDLC), or can be prepared from other materials with switchable refractive indices. In the examples of the present application, PDLC materials are used for preparation, but this cannot be a limitation of the present application.

It should be understood that the PDLC material can assume different states under the control of voltage. It means that a voltage can be loaded on each HOE film, and the film state of each HOE film can be switched by controlling the on and off of the voltage. Further, by controlling the frequency of the voltage, the control of the switching frequency of the N time periods can be realized. Optionally, the PDLC material may be a normal-phase PDLC material or a reverse-phase PDLC material.

Exemplarily, FIG. 6 is an exemplary diagram of state switching of a PDLC material provided by an embodiment of the present application. The PDLC material is positive-phase PDLC, which has two states: when the voltage is turned off, it is in a diffractive state, has the focusing function of a lens, and the chief ray has a certain deflection angle, as shown in (a) in Figure 6; When the voltage is turned on, in the transparent state, the focusing function and the deflection angle disappear, as shown in (b) of FIG. 6 . Illustratively, HOE thin films can also be prepared based on reversed-phase PDLC materials. At this time, when the voltage is turned on, it is in a diffractive state, with the focusing function of the lens, and the chief ray has a certain deflection angle; when the voltage is turned off, it is in a transparent state, and the focusing function and deflection angle disappear. For the convenience of description, the HOE films in the examples of this application are all prepared from normal-phase PDLC materials.

Alternatively, the HOE thin film can be prepared by any one of exposure method, electron beam lithography method or nanoimprint method.

Optionally, the preparation method of the HOE film can be as follows: using a parallel laser beam and a focused laser beam with a deflection angle to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate to obtain the HOE film. The specific preparation method will be described in detail below, and will not be repeated here.

The preparation method of the HOE lens 410 is as follows: the HOE lens is obtained by laminating M layers of the above-mentioned HOE films. Optionally, each of the M layers is prepared using focused lasers with different focal lengths and different deflection angles, respectively.

It should be understood that, in an automobile, the above-mentioned light-transmitting plane may be a windshield or a glass near the windshield, a reflector, or the like. In addition, since the vehicle-mounted HUD is used as an example in the following embodiments, for the convenience of description, the light-transmitting plane is described as a windshield in the embodiments of the present application.

Optionally, the image projection device 420 may also be referred to as a HUD optical machine, and is used to project the light rays of the image generated by the PGU 421 into different areas of the HOE lens 410 . The image projection device 420 can be placed in the console under the windshield, or can be placed in other positions near the windshield, as long as the reflected energy of the image light projected by it through different areas of the HOE lens 410 is different on the outside of the windshield. It only needs to present a corresponding virtual image at the depth, which is not limited in this application.

Optionally, the N projection images include: a first projection image and a second projection image. The first projected image is used to display instrument information, and the second projected image is used to display augmented reality image information.

Optionally, the optical mirror group 422 may include two curved mirrors; alternatively, may include one curved mirror and one flat mirror; alternatively, may include one curved mirror and one or more lenses; or alternatively, may include one For the plane mirror and the lens, the present application does not limit the composition of the optical lens group 422 .

Exemplarily, the optical mirror group 422 includes: a flat mirror M1 and a curved mirror M2, the flat mirror M1 and the curved mirror M2 are located between the HOE lens 410 and the PGU 421, and the N projected images are reflected by the flat mirror M1 and the curved surface. Mirror M2 reflects to HOE lens 410 .

It should be understood that the HOE lens 410 may be attached to the outer side of the windshield, or may be attached to the inner side of the windshield, and may also be used as an interlayer of the windshield, which is not limited in this application.

Preferably, in the embodiment of the present application, the HOE lens 410 is attached to the inner side of the windshield. This is because the reflectivity is about 10% when reflected through the existing windshield; and when the HOE lens 410 is attached to the inside of the windshield, the HUD image is reflected through the HOE lens 410, and the reflection efficiency is above 50%. As a result, image brightness can be improved while power consumption can be reduced.

In the embodiment of the present application, the depth and imaging position of the virtual image are realized by controlling the focal length and deflection angle of the HOE lens, not by controlling the distance between different image areas and the curved mirror, so no special HUD back-end optics are required. The lens group design reduces the difficulty of optical design and processing.

In the embodiments of the present application, since the HOE lens has a lens function when at least one layer of thin film in the HOE lens is in a diffractive state, it can magnify the image from the HUD, thereby further improving the field of view of the system. In addition, the existing HUD uses the windshield to reflect the HUD image. Since both the inner and outer surfaces of the glass reflect the image, and there is a certain deviation, ghost images will occur. However, in the HOE lens used in this application, the reflection on the image area when at least one layer of the film is in a diffractive state belongs to the diffraction principle, and usually only diffracts once, and the diffraction angle is different from the reflection angle of the windshield. Therefore, the user will only observe one diffraction image of the HUD, but will not observe the reflection images on the inside and outside of the windshield, and will not observe ghosting.

Exemplarily, the specific structure of the head-up display device according to the embodiment of the present application will be described in detail below with reference to FIGS. 7 to 9 .

FIG. 7 is a structural example diagram of a dual-screen head-up display device provided by an embodiment of the present application.

As shown in FIG. 7 , the head-up display device is mainly composed of an image projection device, a windshield, and a HOE lens. Wherein, the HOE lens includes a layer of HOE film, which is attached to the inner side of the windshield, and a square wave voltage is loaded on the HOE film. The image projection device includes a PGU, a flat mirror M ₁ and a curved mirror M ₂ . The PGU continuously and alternately generates two images according to the switching frequency of the thin film state, and the time interval between the switching of the two images is the half cycle of the square wave voltage.

Specifically, when the voltage is 0, that is, when the voltage is turned off, the HOE lens is in a diffractive state. At this time, the focal length of the HOE lens is f ₀ and the deflection angle is Δθ, which together with other lenses in the HUD optical machine makes an image generated by the PGU Imaged at screen B, as shown in (a) of FIG. 8 . When the voltage is not 0, that is, when the voltage is turned on, it is in a transparent state, and the focal length and deflection angle are 0. Under the action of other lenses in the HUD optical machine, another image generated by the PGU is imaged at the A screen, as shown in Figure 8 (b) shown in Fig. And by controlling the frequency of the square wave voltage, for example, the frequency of the control voltage is greater than 24Hz, so as to use the human eye persistence effect, so that the driver can observe the virtual image at the A screen and the B screen at the same time.

It should also be understood that the above-mentioned embodiment is only an example. In actual operation, the imaging position can be controlled by controlling the direction and size of the deflection angle; or the imaging distance can be controlled by controlling the size or positive or negative of the focal length. Not limited.

In this embodiment, only one PGU can be used to realize dual-screen display. Moreover, by controlling the switching frequency, focal length and deflection angle of the film state, the driver can observe the closer A screen and the far B screen at the same time, and the images of the A screen and the B screen do not overlap each other and do not interfere with each other.

FIG. 9 is a structural example diagram of a four-screen head-up display device provided by an embodiment of the present application. As shown in FIG. 9 , the head-up display device is mainly composed of an image projection device, a windshield, and a HOE lens. The HOE lens includes two layers of HOE films attached to the inside of the windshield, voltages are respectively applied to the two layers of HOE films, and the deflection angles of the two layers of HOE films in a diffractive state are θ ₁ and θ ₂ respectively. The image projection device includes a PGU, a flat mirror M ₁ and a curved mirror M ₂ . In actual operation, the film state of each HOE film is switched by the opening and closing of the voltage, so that the HOE lens presents four different focal lengths and deflection angles respectively in four time periods, and controls the PGU to alternately generate correspondingly in the four time periods four images. In this embodiment, four periods of time are taken as one period, and the number of periods per unit time can be controlled or the switching frequency of the four periods of time, that is, the voltage frequency, can be controlled, so that the human eye persistence effect can be used, so that the driver can At the same time, the virtual images at screen A, screen B, screen C and screen D were observed.

Exemplarily, as shown in Figure 9:

At time period t1: the voltages of both HOE 1 and HOE 2 are turned on. At this time, both HOE 1 and HOE 2 are in a transparent state, and the focal length and deflection angle are both 0, so the virtual image of image 1 corresponding to time period 1 is in the A screen of depth 1.

At period t2: the voltage of HOE 1 is turned off, and the voltage of HOE 2 is turned on. At this time, HOE 2 is in a transparent state, the focal length and deflection angle are 0; HOE 1 is in a diffractive state, the focal length is not 0, and the deflection angle is θ ₁ , so the virtual image of image 2 corresponding to time period 2 is deflected by θ ₁ , and is at depth 2 B Screen.

At period t3: the voltage of HOE 1 is turned on, and the voltage of HOE 2 is turned off. At this time, HOE 1 is in the transparent state, the focal length and deflection angle are 0; HOE 2 is in the diffractive state, the focal length is not 0, and the deflection angle is θ ₂ . Therefore, the virtual image of image 3 corresponding to time period 3 is deflected by θ ₂ , and is at depth 3 C Screen.

At period t4: both HOE 1 and HOE 2 voltages are turned off. At this time, both HOE 1 and HOE 2 are in the diffraction state, the focal length is not 0, the deflection angle of HOE 1 is θ ₁ , and the deflection angle of HOE 2 is θ ₂ , so the virtual image of image 4 corresponding to time period 4 is deflected by θ ₁ + θ ₂ , D-screen at depth 4.

In this embodiment, only one PGU can be used to realize four-screen display.

It should also be understood that the above-mentioned embodiment is only an example. In actual operation, the imaging position can be controlled by controlling the direction and size of the deflection angle; or the imaging distance can be controlled by controlling the size or positive or negative of the focal length. not limited

Further, you can use 3 layers of HOE film to achieve 8-screen display, or 5 layers of HOE film to achieve 16-screen display, ..., or M layers of HOE film to achieve 2 ^M -screen display.

It should be understood that HUD display with three or more screens can also be realized by controlling the switching mode of the voltage or the focal length and deflection angle of the film when the film is in the diffractive state, providing a richer stereoscopic image display for AR navigation.

FIG. 10 is an example diagram of a method for preparing an HOE lens provided in an embodiment of the present application. The working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, wherein N is a positive integer greater than or equal to 2. The HOE lens includes M layers of variable focus HOE films, where M is a positive integer;

As shown in FIG. 10 , the manufacturing method 900 of the HOE lens includes steps S910 and S920. These steps are described in detail below.

S910, using a parallel laser beam and a focused laser beam with a deflection angle to interfere with each other on the polymer dispersed liquid crystal PDLC holographic dry plate to obtain the HOE film. Specifically, as shown in FIG. 11 .

It should be understood that the two laser beams may be emitted by the same laser and obtained by splitting light by a light splitting device.

Optionally, the deflection angle of the focused laser needs to be defined according to the specifications of the HUD used in actual operation. Common deflection angles may be 2° to 15°.

Optionally, in addition to the exposure method, the method for fabricating the HOE thin film also includes electron beam lithography, nano-imprinting, etc., which is not limited in this application.

It should be understood that the HOE film has at least two film states, and the film states include a transparent state and a diffractive state. By separately controlling the film state of each HOE film, the HOE lens corresponds to different focal lengths and different deflection angles in N time periods.

It should be understood that if the film state of the HOE film is transparent, the HOE film does not have a focusing function and there is no deflection angle; if the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle.

S920, laminating the M layers of HOE films to obtain an HOE lens.

Optionally, each of the M layers can be prepared using focused lasers with different focal lengths and different deflection angles, respectively.

Optionally, the deflection angle of the HOE lens may be the sum of the deflection angles of all the HOE films in the diffractive state in the M-layer HOE films.

Optionally, the relationship between M and N may be: N=2 ^M .

FIG. 12 is an example diagram of a head-up display method provided by an embodiment of the present application. As shown in FIG. 12 , the head-up display method 1100 is implemented in a head-up display device 400. The head-up display device 400 includes: a zoomable holographic optical element HOE lens and an image projection device; the HOE lens is attached to the light-transmitting plane, and the HOE lens The working sequence includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles respectively in the N time periods, where N is a positive integer greater than or equal to 2; the image projection device includes an image generation module PGU and an optical lens group, The PGU is used to generate N projection images corresponding to the N time periods.

The head-up display method 1100 includes step S1110 : projecting the N projection images to the HOE lens through the optical lens group, and through reflection by the HOE lens, the virtual images of the N projection images are focused to different depths outside the light transmission plane.

Optionally, if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and has no deflection angle; if the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle.

Optionally, each HOE film in the M layers of HOE films has different focal lengths and different deflection angles respectively when in the diffractive state.

Optionally, the deflection angle of the HOE film in the diffractive state is 2° to 15°, and the deflection angle of the HOE lens is the sum of deflection angles of all the HOE films in the diffractive state in the M-layer HOE films.

Optionally, the relationship between M and N is: N=2 ^M .

Optionally, the HOE thin film is prepared by any one of exposure method, electron beam lithography method or nanoimprint method.

Optionally, the preparation method of the HOE lens is as follows: a beam of parallel laser and a beam of focused laser with a deflection angle are used to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate to obtain a HOE film; M layers of HOE films are laminated to obtain The HOE lens, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles, respectively.

Optionally, the N projection images include: a first projection image and a second projection image, the first projection image is used for displaying instrument information, and the second projection image is used for displaying augmented reality image information.

Optionally, the optical mirror group includes: a flat mirror and a curved mirror, the flat mirror and the curved mirror are located between the HOE lens and the PGU, and the N projected images are reflected to the HOE lens through the flat mirror and the curved mirror.

An embodiment of the present application further provides a vehicle, including the above head-up display device 400 . It should be understood that the vehicle may be an electric vehicle, for example, a pure electric vehicle, an extended-range electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a new energy vehicle, etc., which are not specifically limited in this application.

An embodiment of the present application further provides an in-vehicle system, including the above head-up display device 400 .

The embodiment of the present application also provides a method for controlling a HOE lens, the HOE lens includes M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state, The method includes: controlling the film state of each HOE film respectively, so that the HOE lens corresponds to different focal lengths and different deflection angles respectively in the N time periods.

An embodiment of the present application further provides a controller, the controller includes an input and output interface, a processor and a memory, the processor is used to control the input and output interface to send and receive signals or information, the memory is used to store a computer program, the processor is used for The computer program is called and executed from the memory, so that the controller executes the above-described method 900, and/or executes the method 1100, and/or executes the above-described control method of the HOE lens. Embodiments of the present application also provide a computer program product containing instructions, when the computer program product is run on a computer, the computer program product causes the computer to execute the above-mentioned method 900, and/or execute the method 1100, and/or execute the above-mentioned control of the HOE lens method.

Embodiments of the present application further provide a computer-readable storage medium, where the computer-readable medium stores program codes for device execution, where the program codes include instructions for executing the foregoing method 900 and/or executing the method 1100 , and/or an instruction to execute the above-mentioned HOE lens control method.

An embodiment of the present application further provides a chip, where the chip includes a processor and a data interface, the processor reads an instruction stored in a memory through the data interface, and executes the above method 900 and/or the method 1100, And/or implement the above-mentioned control method of the HOE lens.

Optionally, as an implementation manner, the chip may further include a memory, in which instructions are stored, the processor is configured to execute the instructions stored in the memory, and when the instructions are executed, the The processor is configured to execute the above method 900, and/or execute the method 1100, and/or execute the above control method of the HOE lens.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above may refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

The above are only specific implementations of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A head-up display device, comprising:

Zoomable holographic optical element HOE lens and image projection device;

The HOE lens is attached to the light-transmitting plane, the working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, where N is greater than or a positive integer equal to 2;

The image projection device includes an image generation module PGU and an optical mirror group, the PGU is used to generate N projection images corresponding to the N time periods, and the optical mirror group is used to project the N projection images to The HOE lens is reflected by the HOE lens, so that the virtual images of the N projected images are focused to different depths outside the light transmission plane.
The device according to claim 1, wherein the HOE lens comprises M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state, By separately controlling the film state of each HOE film, the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods.
The device of claim 2, wherein if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle;

If the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle.
The device according to claim 2 or 3, wherein each HOE film in the M layers of HOE films has different focal lengths and different deflection angles respectively when in a diffractive state.
The device according to claim 3 or 4, wherein the deflection angle of the HOE film in a diffractive state is 2° to 15°, and the deflection angle of the HOE lens is that in the M-layer HOE film in a diffractive state The sum of the deflection angles of all HOE films in the state.
The apparatus according to any one of claims 2 to 5, wherein the relationship between M and N is: N=2 M .
The device according to any one of claims 2 to 6, wherein the HOE film is prepared by any one of an exposure method, an electron beam lithography method or a nanoimprint method.
The device according to any one of claims 2 to 7, wherein the preparation method of the HOE lens is as follows:

Using a beam of parallel laser and a beam of focused laser with a deflection angle to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate to obtain the HOE film;

The HOE lens is obtained by laminating M layers of the HOE films, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles respectively.
The device according to any one of claims 2 to 8, wherein the device further comprises:

a controller, the controller is configured to control the PGU to generate N projection images corresponding to the N time periods; and/or,

It is used to control the film state of each HOE film, so that the HOE lens corresponds to different focal lengths and different deflection angles respectively in the N time periods.
The device according to any one of claims 1 to 9, wherein a unit time includes K working cycles, each working cycle includes the N time periods, and K is greater than or equal to a preset threshold.
The apparatus according to any one of claims 1 to 10, wherein the N projection images comprise:

A first projection image and a second projection image, where the first projection image is used to display instrument information, and the second projection image is used to display augmented reality image information.
The device according to any one of claims 1 to 11, wherein the optical lens group comprises:

A flat mirror and a curved mirror, the flat mirror and the curved mirror are located between the HOE lens and the PGU, and the N projected images are reflected by the flat mirror and the curved mirror to the HOE lens.
A head-up display method, characterized in that the head-up display method is implemented in a head-up display device, the head-up display device comprising: a zoomable holographic optical element HOE lens and an image projection device;

The HOE lens is attached to the light-transmitting plane, the working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, where N is greater than or a positive integer equal to 2;

The image projection device includes an image generation module PGU and an optical lens group, and the PGU is used to generate N projection images corresponding to the N time periods;

The head-up display method includes:

The N projection images are projected to the HOE lens through the optical lens group, and after reflection by the HOE lens, the virtual images of the N projection images are focused to different depths outside the light transmission plane.
The method of claim 13, wherein the HOE lens comprises M layers of HOE films, where M is a positive integer; the HOE film has at least two film states, and the film states include a transparent state and a diffractive state, By separately controlling the film state of each HOE film, the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods.
The method of claim 14, wherein if the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle;

If the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle.
The method of claim 15, wherein each HOE film in the M layers of HOE films has different focal lengths and different deflection angles respectively when in a diffractive state.
The method according to claim 15 or 16, characterized in that the deflection angle of the HOE film in a diffractive state is 2° to 15°, and the deflection angle of the HOE lens is that the M-layer HOE film is in a diffractive state. The sum of the deflection angles of all HOE films in the state.
The method according to any one of claims 14 to 17, wherein the relationship between M and N is: N=2 M .
The method according to any one of claims 14 to 18, wherein the HOE film is prepared by any one of an exposure method, an electron beam lithography method or a nanoimprint method.
The method according to any one of claims 14 to 19, wherein the preparation method of the HOE lens is as follows:

Using a beam of parallel laser and a beam of focused laser with a deflection angle to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate to obtain the HOE film;

The HOE lens is obtained by laminating M layers of the HOE films, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles respectively.
The method according to any one of claims 13 to 20, wherein a unit time includes K working cycles, each working cycle includes the N time periods, and K is greater than or equal to a preset threshold.
The method according to any one of claims 13 to 21, wherein the N projection images comprise:

A first projection image and a second projection image, where the first projection image is used to display instrument information, and the second projection image is used to display augmented reality image information.
The method according to any one of claims 13 to 22, wherein the optical lens group comprises:

A flat mirror and a curved mirror, the flat mirror and the curved mirror are located between the HOE lens and the PGU, and the N projected images are reflected by the flat mirror and the curved mirror to the HOE lens.
A method for preparing a variable-focus holographic optical element HOE lens, wherein the working sequence of the HOE lens includes N time periods, and the HOE lens corresponds to different focal lengths and different deflection angles in the N time periods, respectively, Among them, N is a positive integer greater than or equal to 2;

The HOE lens includes M layers of variable-focus HOE films, where M is a positive integer;

The preparation method of the HOE lens is as follows:

Using a beam of parallel laser and a beam of focused laser with a deflection angle to interfere with each other on a polymer dispersed liquid crystal PDLC holographic dry plate to obtain the HOE film;

The HOE lens is obtained by laminating M layers of the HOE films, wherein each of the M layers is prepared by using focused lasers with different focal lengths and different deflection angles respectively.
The method according to claim 24, wherein the HOE film has at least two film states, the film states include a transparent state and a diffractive state, and the HOE film is controlled separately by controlling the film state of each layer of the HOE film to make the HOE film The lenses correspond to different focal lengths and different deflection angles respectively in the N time periods.
The method of claim 25, wherein:

If the film state of the HOE film is a transparent state, the HOE film does not have a focusing function and does not have a deflection angle;

If the film state of the HOE film is a diffractive state, the HOE film has a focusing function and has a deflection angle.
The method of claim 26, wherein the deflection angle of the HOE film in the diffractive state is 2° to 15°, and the deflection angle of the HOE lens is the deflection angle of the M-layer HOE film in the diffractive state. Sum of deflection angles of all HOE films.
The method according to any one of claims 24 to 27, wherein the relationship between M and N is: N=2 M .
A vehicle, characterized by comprising the head-up display device according to any one of claims 1 to 12.
An in-vehicle system, comprising the head-up display device according to any one of claims 1 to 12.
A computer program comprising a method for carrying out the head-up display method described in any one of claims 13 to 23, and/or a method for carrying out the preparation method described in any one of claims 24 to 28. instruction.
A computer-readable medium, characterized in that it is used for storing a computer program, the computer program comprising the head-up display method for performing any one of claims 13 to 23, and/or for use in claims 24 to 28 Instructions for the method of preparation of any one of.