CN114647089A

CN114647089A - Head-up display and vehicle

Info

Publication number: CN114647089A
Application number: CN202210378799.2A
Authority: CN
Inventors: 杨苡甄
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; Yecheng Optoelectronics Wuxi Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2022-04-12
Filing date: 2022-04-12
Publication date: 2022-06-21
Also published as: TWI827004B; TW202340798A

Abstract

The embodiment of the application provides a head-up display and a vehicle. The head-up display includes an image source, a polarization splitting element, a polarization conversion element, and a reflective assembly. The image source is used for emitting circularly polarized light. The polarization light splitting element is used for reflecting S-state polarized light in circularly polarized light and transmitting P-state polarized light in the circularly polarized light. The S-state polarized light reflected by the polarization beam splitter is defined as first image light. The polarization conversion element is used for converting P-state polarized light into S-state polarized light. Defining the S-state polarized light converted by the polarization conversion element as second image light. The reflection assembly is used for reflecting the first image light and the second image light to the projection medium to form a first virtual image and a second virtual image respectively. The first virtual image and the second virtual image have different virtual image distances and different field angles.

Description

Head-up display and vehicle

Technical Field

The application relates to the technical field of display, in particular to a head-up display and a vehicle.

Background

Existing heads-up displays have only a single virtual image distance and a single viewing angle. However, with the development of head-up displays, a single virtual image distance and a single viewing angle have not been able to satisfy driving requirements.

Disclosure of Invention

A first aspect of the present application provides a heads up display. This new line display includes:

the image source is used for emitting image light, and the image light is circularly polarized light;

the polarization light splitting element is positioned on the light emergent side of the image source and used for reflecting S-state polarized light in the circularly polarized light to start a first light path and transmitting P-state polarized light in the circularly polarized light to start a second light path, wherein the S-state polarized light reflected by the polarization light splitting element is defined as first image light;

the polarization conversion element is positioned on the second light path and is used for converting the P-state polarized light into S-state polarized light, wherein the S-state polarized light converted by the polarization conversion element is defined as second image light; and

and the reflection assembly is positioned on the first light path and the second light path and used for reflecting the first image light and the second image light to a projection medium to form a first virtual image and a second virtual image respectively, wherein the virtual image distance and the field angle of the first virtual image and the virtual image distance and the field angle of the second virtual image are different.

The head-up display divides image light into P-state polarized light and S-state polarized light which are transmitted on different optical paths by arranging the polarization light splitting element, wherein the S-state polarized light reflected by the polarization light splitting element is used as first image light. The P-state polarized light transmitted by the polarization beam splitter is converted into S-state polarized light by the polarization conversion element to serve as second image light. And after the first image light and the second image light are reflected to the projection medium through the reflection assembly, virtual images of two virtual image distances and two field angles are generated simultaneously, so that the driving safety is favorably improved.

A second aspect of the present application provides a vehicle, comprising:

a windshield; and

the head-up display of the first aspect;

wherein the windshield is the projection medium.

The vehicle includes the head-up display of the first aspect, and therefore, has at least the same advantages as the head-up display of the first aspect, and will not be described in detail.

Drawings

Fig. 1 is a schematic structural diagram of a head-up display according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram showing the relationship between the reflectance of P-state polarized light and S-state polarized light and the tilt angle of the windshield.

Fig. 3 is a schematic diagram of an image source in fig. 1.

Description of the main element symbols:

head-up display 100

Image source 10

Laser light source 11

Red laser 111

Green laser 112

Blue laser 113

Beam combining assembly 12

MEMS micro-mirror 13

Polarization splitting element 20

Mirror 30

Polarization conversion element 40

First diffusion member 51

Second diffusion member 52

Reflection assembly 60

First free-form surface mirror 61

Second free-form surface mirror 62

First virtual image VI1

Second virtual image VI2

Windshield 200

Detailed Description

Head-up display (HUD) technology, also called head-up display technology, has been increasingly used in the automotive field, aerospace field, and marine field in recent years. For example, the method can be applied to vehicles, and can also be applied to other vehicles such as airplanes, space flight and aviation aircrafts, ships and the like. For convenience of description, in the present application, a vehicle-mounted HUD is described as an example. It should be understood that this is not a limitation of the present application.

Specifically, the head-up display projects important driving related information (such as driving speed, battery voltage, water tank temperature, engine rotating speed, vehicle oil consumption, navigation route and the like) on a windshield by using the principle of optical reflection, and the driving related information is reflected into eyes of a driver in a balanced manner to assist the driver in driving the vehicle, so that the driver is prevented from being distracted by lowering head to see an instrument panel in the driving process, the driving safety factor is improved, and better driving experience can be brought at the same time.

The Virtual Image Distance (VID) is the Distance from the human eye to the Virtual Image. The Field of view (FOV) is the angle that the driver's eyes make to the horizontal and vertical edges of the virtual image, centered on.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments.

Fig. 1 is a schematic structural diagram of a head-up display according to an embodiment of the present disclosure. As shown in fig. 1, the head-up display 100 includes an image source 10, a polarization splitting element 20, a first diffusing element 51, a mirror 30, a polarization conversion element 40, a second diffusing element 52, and a reflective assembly 60. The reflection assembly 60 includes a first free-form surface mirror 61 and a second free-form surface mirror 62.

The image source 10 is used to emit image light. The image light is circularly polarized light. Polarizing beamsplitter 20 is positioned on the light exit side of image source 10. The polarization beam splitter 20 is configured to reflect the S-state polarized light in the image light to initiate the first optical path, and transmit the P-state polarized light in the image light to initiate the second optical path. The Polarization Beam Splitter 20 is, for example, a Polarization Beam Splitter (PBS), but is not limited thereto. For example, the polarization splitting element 20 may also be an optical film having a polarization transflective function, which is capable of transmitting P-state polarized light and reflecting S-state polarized light. Specifically, the optical film includes, for example, a plurality of film layers having different refractive indices combined in a certain stacking order.

On the first optical path, a first diffusing element 51, a first free-form surface mirror 61, and a second free-form surface mirror 62 are provided in this order. On the second optical path, a reflecting mirror 30, a polarization conversion element 40, a second diffusing element 52, a first free-form surface mirror 61, and a second free-form surface mirror 62 are provided in this order.

The first and second diffusing elements 51 and 52 serve to uniformize image light and change the angle of field. The first and second diffusing elements 51 and 52 are diffusing sheets or microlens array films to eliminate the problems of laser speckle and directional light. The diffusion sheet comprises at least one of a round diffusion sheet capable of converting an incident light beam into round light spots, an oval diffusion sheet capable of converting the incident light beam into oval light spots and a flat-top diffusion sheet capable of converting the incident light beam into flat-top distributed light spots.

The first and second free-form surface mirrors 61 and 62 are used to correct and change the magnification of the virtual image. At least one of the first free-form surface mirror 61 and the second free-form surface mirror 62 is a position-adjustable free-form surface mirror. This position adjustable free-form surface mirror can be in presetting angle scope internal rotation, translation or swing to adjust the position of the image of new line display 100 on the projection medium, thereby make the image can clearly, show completely, make the virtual image that the navigating mate can see clearly HUD projection demonstration. In other embodiments, the reflective assembly 60 is not limited to including two free-form mirrors, for example, it may include more than three free-form mirrors.

The polarization conversion element 40 is used to convert P-state polarized light into S-state polarized light. Polarization conversion element 40 may be a half-wave plate or two quarter-wave plates. When the polarization conversion element 40 is a half-wave plate, the P-state polarized light is converted once by the half-wave plate to obtain S-state polarized light. In the case that the polarization conversion element 40 is a quarter-wave plate, the P-state polarized light needs to pass through two quarter-wave plates in sequence, and is converted twice to obtain S-state polarized light.

Specifically, after the image light generated by the image source 10 passes through the polarization beam splitter 20, the S-polarized light in the image light is reflected. The S-state polarized light reflected by the polarization splitting element 20 is defined as the first image light. The first image light is uniformized and has a small angle of view after passing through the first diffusing element 51. Then, the first image light is reflected to a projection medium (e.g., a windshield 200 of a vehicle) via the first free-form surface mirror 61 and the second free-form surface mirror 62, respectively, to form a first virtual image VI 1. After the first virtual image VI1 is incident on the human eye, it appears as a near image.

After the image light generated by the image source 10 passes through the polarization beam splitter 20, the P-state polarized light in the image light is transmitted. The P-state polarized light passes through the mirror 30 and is then reflected to the polarization conversion element 40. The polarization conversion element 40 converts the P-state polarized light into S-state polarized light. The S-state polarized light converted by the polarization conversion element 40 is defined as second image light. The second image light is uniformized and has a large angle of view by the second diffusing element 52. Then, the second image light is reflected to a projection medium (e.g., a windshield 200 of a vehicle) to form a second virtual image VI2 after passing through the first and second free-form surface mirrors 61 and 62, respectively. The second virtual image VI2 appears as a distant image after being incident on the human eye.

The virtual image distance and the angle of view of the first virtual image VI1 and the second virtual image VI2 are different for the same driver. The virtual image distance VID1 of the first virtual image VI1 is smaller than the virtual image distance VID2 of the second virtual image VI 2. The field angle of the first virtual image VI1 (HFOV1 × VFOV1) is smaller than the field angle of the second virtual image VI2 (HFOV2 × VFOV 2).

Specifically, the first virtual image VI1 and the second virtual image VI2 are projected into the human eye simultaneously. Simple information such as speed and fuel amount can be displayed in the close-up image (the first virtual image VI1), which is generally located at a distance of about 1.8m-2.5m from the driver, so that the driver has the best response speed in an emergency. Information to be fused with the real world, such as road condition information, navigation information, etc., may be displayed in the remote image (the second virtual image VI2), which may be located 7m away from the driver for matching with the distance of the external road.

The head-up display divides image light into P-state polarized light and S-state polarized light which are transmitted on different optical paths by arranging the polarization light splitting element, wherein the S-state polarized light reflected by the polarization light splitting element is used as first image light. The P-state polarized light transmitted by the polarization beam splitter is converted into S-state polarized light by the polarization conversion element to serve as second image light. And after the first image light and the second image light are reflected to the projection medium through the reflection assembly, virtual images of two virtual image distances and two field angles are generated simultaneously, and the driving safety is improved. In addition, in the head-up display, the polarization light splitting element is arranged for polarization light splitting, and the first light path and the second light path are folded, so that the light path is more compact, and the size of the head-up display is reduced.

In some embodiments, the angle of inclination α of the windshield 200 is 40 to 50 degrees. The inclination angle α of the windshield 200 indicates the inclination angle of the windshield 200 compared to the driving center console. Fig. 2 is a schematic diagram showing the relationship between the reflectance of P-state polarized light and S-state polarized light and the tilt angle of the windshield. As shown in fig. 2, the inclination angle of the windshield is 40 degrees to 50 degrees, the reflectance of P-state polarized light is extremely low, and the reflectance of S-state polarized light is approximately 20%. Therefore, in the embodiment of the present application, the S-state polarized light is used as the first image light and the second image light, which is beneficial to improving the utilization rate of the light source.

Fig. 3 is a schematic diagram of an image source in fig. 1. The image source 10 is a Laser Beam Scanning (LBS). As shown in fig. 3, the laser beam scanner includes a laser light source 11, a beam combining assembly 12, and a Micro-Electro-Mechanical System (MEMS) Micro-mirror 13. The laser light source 11 is used for emitting laser light of different colors. The beam combining component 12 is used for combining the laser lights with different colors. The MEMS micro-mirror 13 is configured to reflect laser light of different colors as image light. In the present embodiment, the laser light source 11 includes a red laser 111 for emitting red laser light, a green laser 112 for emitting green laser light, and a blue laser 113 for emitting blue laser light. The beam combining component 12 includes, for example, a first beam splitter (not shown) facing the red laser 111, a second beam splitter facing the green laser 112, and a third beam splitter facing the blue laser 113. The red laser emitted by the red laser 111 is reflected by the first beam splitter and emitted. The green laser emitted by the green laser 112 is reflected by the second beam splitter and then emitted to the first beam splitter, and the blue laser emitted by the blue laser 113 mixed with the red laser and penetrating through the first beam splitter is reflected by the third beam splitter and then emitted to the first beam splitter and the second beam splitter in sequence, and is mixed with the red laser and the green laser.

In other embodiments, image source 10 may further include a collimating lens (not shown) between laser light source 11 and beam combining assembly 12, for example, to allow the laser light to act in parallel and uniformly over longer distances.

Compared with an image source such as a Liquid Crystal Display (LCD), a Liquid Crystal on Silicon (LCoS) Display, a Digital Light Processing (DLP) Display and the like, the LBS has the advantages of small size, low heat power consumption, no need of adjusting focal length when being arranged, direct imaging on a windshield, strong image penetration, high color contrast, capability of providing optimized frameless HUD Display and the like.

A second aspect of the present application provides a vehicle. The vehicle comprises a windshield and the head-up display. The windshield is the projection medium. The vehicle includes the head-up display of the first aspect, and therefore, has at least the same advantages as the head-up display of the first aspect, and will not be described in detail.

Although the present application has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present application.

Claims

1. A heads-up display, comprising:

2. The heads-up display of claim 1 wherein the virtual image distance of the first virtual image is less than the virtual image distance of the second virtual image; the field angle of the first virtual image is smaller than the field angle of the second virtual image.

3. The head-up display of claim 1, further comprising a first diffusing element and a second diffusing element;

the first diffusion element is positioned between the polarization light splitting element and the reflection assembly so as to homogenize the first image light;

the second diffusion element is positioned between the polarization conversion element and the reflection assembly to homogenize the second image light.

4. The heads-up display of claim 3 wherein the first and second diffusing elements are diffusers or micro-lens array films, the diffusers including at least one of circular diffusers capable of converting an incident light beam into circular spots, elliptical diffusers capable of converting an incident light beam into elliptical spots, and flat-top diffusers capable of converting an incident light beam into flat-top distributed spots.

5. The heads-up display of claim 1 further comprising a mirror;

the reflecting mirror is positioned on the second light path to reflect the P-state polarized light transmitted by the polarization beam splitting element to the polarization conversion element.

6. The heads-up display of claim 1 wherein the reflective assembly includes at least one free-form mirror that is adjustable in position to vary the magnification of the first and second virtual images.

7. The heads-up display of claim 1 wherein the polarization conversion element is a half-wave plate or two quarter-wave plates.

8. The heads-up display of any one of claims 1 to 7 wherein the image source is a laser beam scanner comprising:

a plurality of laser light sources for emitting laser lights of different colors; and

and the MEMS micro-mirror is used for reflecting the laser light with different colors to serve as the image light.

9. A vehicle, characterized by comprising:

a windshield; and

the heads-up display of any one of claims 1 to 8;

wherein the windshield is the projection medium.

10. The vehicle of claim 9, characterized in that the angle of inclination of the windshield relative to a center console of the vehicle is 40 to 50 degrees.