CN117331271A

CN117331271A - Projection device, display equipment and vehicle

Info

Publication number: CN117331271A
Application number: CN202210727252.9A
Authority: CN
Inventors: 郑定喆; 方元戎; 陈彦哲
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2024-01-02
Also published as: CN115542644A

Abstract

The embodiment of the application provides a projection device, a display device and a vehicle, relates to the technical field of light display, and mainly aims to provide a three-dimensional stereoscopic projection device with high imaging quality without losing image resolution, which is applied to specific scenes such as near-eye display, head-up display, projection display device and vehicle-mounted display device. The projection device includes: a display module and a light splitting unit; the display module is used for generating a first light beam and emitting the first light beam; the first light beam includes first polarized light carrying left eye image information and second polarized light carrying right eye image information and having a polarization direction perpendicular to the first polarized light. The light splitting unit is located at the light emitting side of the display module, i.e. located on the propagation path of the first light beam, and is configured to make the first polarized light and/or the second polarized light in the first light beam emit in different directions by making the first light beam generate birefringence.

Description

Projection device, display equipment and vehicle

Technical Field

The present disclosure relates to the field of optical display technologies, and in particular, to a projection apparatus, a display device, and a vehicle.

Background

The Head-Up Display device (HUD) is a Head-Up Display device, and can be applied to automobiles for projecting instrument panels or other driving and road condition information onto front windshields, so that a driver can know various instrument information of the automobiles without transferring the sight to the instrument panels in the driving process.

In order to better fuse the projected information with the driving scene, a three-dimensional display (i.e., spectroscopic stereo display) technology based on the binocular parallax principle, particularly an naked eye spectroscopic stereo display technology, is beginning to be applied to the HUD. The naked eye type light splitting stereoscopic display technology can cheat the brain of an observer by providing slightly different images for the left eye and the right eye of the observer respectively, so that the observer can generate a 3D visual effect without wearing three-dimensional glasses.

The naked eye type spectroscopic stereo display mainly comprises a light barrier type and a micro-column lens type. However, both of these naked eye spectroscopic stereoscopic display techniques lose resolution of the image, i.e., affect image quality.

Disclosure of Invention

The embodiment of the application provides a projection device, display equipment comprising the projection device and a vehicle comprising the projection device, and mainly aims to provide a three-dimensional stereoscopic projection device with high imaging quality, wherein the three-dimensional stereoscopic projection device does not lose image resolution.

In order to achieve the above purpose, the present application adopts the following technical scheme:

in a first aspect, the present application provides a projection apparatus, which may be applied to video entertainment and driving-assisting scenes, including but not limited to specific scenes such as near-eye display, head-up display, projector, vehicle-mounted display device, and vehicle lamp, and may be used alone or may be integrated as a component in other devices.

The projection device includes: a display module and a light splitting unit; the display module is used for generating a first light beam and emitting the first light beam; the first light beam includes first polarized light carrying left eye image information and second polarized light carrying right eye image information and having a polarization direction perpendicular to the first polarized light. The light splitting unit is located at the light emitting side of the display module, i.e. located on the propagation path of the first light beam, and is used for carrying out birefringence on the first light beam, so that the first polarized light and the second polarized light in the first light beam are emitted in different directions.

In the first aspect, the first polarized light and the second polarized light may coexist in the first light beam. Alternatively, the display module may generate the first polarized light and the second polarized light simultaneously. In this case, after the first light beam propagates to the beam splitting unit, two beams of refracted light, that is, the first polarized light and the second polarized light, are generated under the action of the beam splitting unit.

In the first aspect, the first polarized light and the second polarized light exist separately in the first light beam. Specifically, the display module sequentially generates the first polarized light, the second polarized light, the first polarized light, and the second polarized light … … at different times according to a certain timing rule. That is, at one instant, the first light beam is a first polarized light and at a different instant, the first light beam is a second polarized light. In this case, in the case where the first light beam is the first polarized light, it is refracted at the first refractive index by the light splitting unit after propagating to the light splitting unit; when the first light beam is the second polarized light, the first light beam is refracted at the second refractive index under the action of the light splitting unit after being transmitted to the light splitting unit; the first refractive index is different from the second refractive index.

That is, in the implementation in which the first polarized light and the second polarized light exist in the first light beam at the same time, the birefringent effect of the light splitting unit may separate the first polarized light and the second polarized light at a certain angle, and further, propagate in different directions, respectively. In the implementation mode that the first polarized light or the second polarized light exists in the first light beam independently, for the first polarized light and the second polarized light with the same original propagation directions, the double refraction effect of the light splitting unit can change the propagation directions of the first polarized light and the second polarized light into different directions, and further the first polarized light and the second polarized light continue to propagate along different directions respectively.

Therefore, in the projection device provided by the application, the display module can generate the first light beam, and in the first light beam, the first polarized light and the second polarized light respectively carry different image information. The light splitting unit has a double refraction effect, and can emit the first polarized light and the second polarized light in the first light beam in different directions, so that the first polarized light and the second polarized light can continuously propagate in different directions. The realization principle can be known, the aim of light splitting three-dimensional display can be achieved without dividing pixels of a display, and further, the projection device can project images with higher resolution.

In a possible implementation manner of the first aspect, the projection device further includes: the projection unit, such as a projection lens group, may be a short-focus lens group or a long-focus lens group. The projection lens group is used for converging a light beam (such as the first light beam) containing image information, so that the light beam is an imaging light beam and is projected outwards.

In a possible implementation manner of the first aspect, the projection unit is located on a path of the first light beam between the display module and the light splitting unit. Thus, the projection unit can converge the first light beam to obtain an imaging light beam, and projects the imaging light beam to the beam splitting unit.

In a possible implementation manner of the first aspect, the projection unit is located on a propagation path of the first polarized light and the second polarized light, i.e. on an light exit side of the light splitting unit. In this way, the projection unit can converge the first polarized light emitted by the light splitting unit to obtain the first polarized imaging light, and converge the second polarized light emitted by the light splitting unit to obtain the second polarized imaging light, and project the first polarized imaging light and the second polarized imaging light.

In a possible implementation manner of the first aspect, the projection device further includes a light diffusing element, which may also be referred to as a diffusion screen. The diffusion screen may be located at the light-emitting side of the light-splitting unit. In the design that the projection unit is located at the light emitting side of the light splitting unit, the diffusion screen may be located between the light splitting unit and the projection unit, so that the diffusion screen may be used for diffusing the first polarized light and the second polarized light emitted by the light splitting unit, so as to improve uniformity of an imaging picture. The diffusion screen may also be located on the light emitting side of the projection unit, i.e. on the projection path of the projection unit, so that the diffusion screen may be used to diffuse the first polarized light and the second polarized light projected by the projection unit, so as to improve the uniformity of the imaging frame. In the above design where the projection unit is located on the propagation path of the first light beam between the display module and the light splitting unit, the diffusion screen may be located on the light emitting side of the light splitting unit. Like this, the diffusion screen can be used for diffusing the first polarization imaging light and the second polarization imaging light that the light splitting unit penetrated, promotes the homogeneity of formation of image picture.

In a possible implementation manner of the first aspect, a diffusion angle of the light diffusing element is less than 20 °. In this way, crosstalk between two light beams caused by excessive diffusion of the first polarized light (or the first polarized imaging light) and the second polarized light (or the second polarized imaging light) can be avoided, and the imaging effect is ensured.

In a possible implementation manner of the first aspect, the projection device further includes: and the first reflecting element is positioned on the path of the first polarized light and the second polarized light after passing through the diffusion screen and is used for reflecting the first polarized light and the second polarized light after being diffused through the diffusion screen. The specific implementation of the first reflective element varies in different application scenarios. For example, when the projection device is integrated with the VR glasses, the first reflecting element may be a projection lens, and the projection lens, the display module, the light splitting unit, the projection unit and the diffusion screen are integrated together in the VR glasses. When the projection device is a projector, the first reflection element may be a projection curtain, and there may be no mechanical connection between the projection curtain and the display module, the light splitting unit, the projection unit, and the diffusion screen.

In a possible implementation manner of the first aspect, the light splitting unit includes a first right angle prism and a second right angle prism, and a maximum side surface of the first right angle prism is bonded with a maximum side surface of the second right angle prism; the first right angle prism and the second right angle prism each comprise a birefringent crystalline material. The maximum side is understood here to be the side of the right-angle prism with the greatest area, i.e. the side on which the hypotenuse of the right-angle triangle is located.

In a possible implementation manner of the first aspect, the light splitting unit includes one or more of a gram-foucault prism, a wollaston prism, a rochon prism and a samming prism.

In a possible implementation manner of the first aspect, the light splitting unit includes a plurality of sets of right angle prisms, each set of right angle prisms including a first right angle prism and a second right angle prism, and a maximum side surface of the first right angle prism is bonded with a maximum side surface of the second right angle prism; the first right angle prism and the second right angle prism each comprise a birefringent crystalline material. The right angle prisms can be integrally formed or independent. In each group of right angle prisms, the angle between the surface of the first right angle prism facing the first light beam (hereinafter referred to as AB surface) and the propagation direction of the light ray in the first light beam incident therein is the same.

Regarding the arrangement manner of the plurality of sets of right-angle prisms, it can be understood that the first light beam emitted by the display module includes a plurality of light beams, and the plurality of light beams are not parallel in absolute meaning. When there is only one first right angle prism, the angles of the different light rays when they are incident on the AB-plane are not absolutely identical. When different light rays are incident to the first right-angle prism at different angles, the included angles between the first polarized light and the second polarized light which are emitted from the second right-angle prism and correspond to the different light rays are different. Thus, crosstalk is likely to occur between the first polarized light and the second polarized light, and the imaging quality of the projected image is affected. Based on this, through adopting multiunit right angle prism to the position of every group right angle prism is designed, makes in every group right angle prism, and the contained angle between the AB face of first right angle prism and the propagation direction of the light in the first light beam of incidence wherein all or most light can all be in the first light beam incident in first right angle prism with the same angle, and then guarantees the contained angle between the first polarized light and the second polarized light that follow in every second right angle prism and shoot out as the same as possible. In this way, crosstalk between the first polarized light and the second polarized light can be avoided, and the imaging quality of the projection image is improved.

In a possible implementation manner of the first aspect, an optical axis direction of the first right angle prism is perpendicular to an optical axis direction of the second right angle prism; the optical axis direction of the first right angle prism is parallel to the AB plane of the first right angle prism. The first light beam is incident into the first right angle prism along the AB surface vertical to the first right angle prism, and reaches the junction of the first right angle prism and the second right angle prism, and the double refraction occurs at the junction.

In a possible implementation manner of the first aspect, the birefringent crystal material is barium metaborate. Compared with other birefringent crystal materials such as calcite, the barium metaborate can reduce the dispersion of the prism on light rays, and further ensure the imaging quality of a projection image.

In a possible implementation manner of the first aspect, the display module includes a light source, a polarization splitting prism, a first modulator and a second modulator; a light source for emitting a second light beam to the polarization beam splitter prism; a polarization splitting prism for reflecting the S-state polarized light in the second light beam to the first modulator and transmitting the P-state polarized light in the second light beam to the second modulator; the first modulator is used for generating first polarized light according to the S-state polarized light and emitting the first polarized light to the polarization beam splitter prism; the second modulator is used for generating second polarized light according to the P-state polarized light and emitting the second polarized light to the polarization beam splitter prism; the polarization beam splitter prism is also used for combining the first polarized light and the second polarized light into a first light beam and transmitting the first light beam to the beam splitter unit. In this implementation manner, in the first light beam generated by the display module, the first polarized light and the second polarized light exist at the same time.

In a possible implementation manner of the first aspect, the display module includes a light source, a polarizer, a modulator, and a polarization converter; a light source for emitting a second light beam to the polarizer; a polarizer for obtaining polarized light from the second light beam and providing it to the modulator; the polarized light is P-state polarized light or S-state polarized light; and a modulator for alternately generating the first polarized light and the third polarized light according to the polarized light. For example, at each first preset time, generating first polarized light according to the polarized light, and at each second preset time, generating third polarized light according to the polarized light; a polarization converter for transmitting the first polarized light to the spectroscopic unit when the first polarized light from the modulator is received; when receiving the second polarized light from the modulator, the third polarized light is converted into the second polarized light and emitted to the spectroscopic unit.

In the above implementation manner, a second preset time exists between every two adjacent first preset times, or, a first preset time exists between every two adjacent second preset times. The third polarized light has the same polarization direction as the first polarized light, but is different from the image information included in the first polarized light. That is, the first light beam generated by the display module at each first preset time is the first polarized light, and the first light beam generated by the display module at each third preset time is the second polarized light. Wherein each third preset time corresponds to a second preset time. The third preset moment may be understood as the moment at which the polarization converter converts the third polarized light into the second polarized light.

In a second aspect, the present application provides a display device, including a processor and any one of the above projection apparatuses, where the processor is configured to send image data to a display module in the projection apparatus. Because the display module in the projection device can generate the first polarized light and the second polarized light carrying different image information, the light splitting unit of the display module in the projection device has double refraction, and the first polarized light and the second polarized light can be emitted in different directions and then are respectively received by the left eye and the right eye of an observer, so that the left eye and the right eye of the observer can see slightly different images, and the visual effect of viewing the 3D image is further generated. According to the realization principle, the aim of light splitting three-dimensional display can be achieved without dividing pixels of a display, and further the display device can display a 3D image with higher resolution.

In one possible implementation, the display device is integrated in a head-up display HUD of a vehicle.

In a third aspect, the present application provides a vehicle including a second reflective element and the display device described above, the display device being mounted on the vehicle for emitting first and second polarized light in different directions to the second reflective element, the second reflective element being for reflecting the first and second polarized light such that the first polarized light is received by one eye of an observer and the second polarized light is received by the other eye of the observer, such that the left and right eyes of the observer view slightly different left and right eye images, respectively, thereby producing a visual effect of viewing a 3D image. According to the realization principle of the projection device, the aim of light splitting three-dimensional display can be achieved without dividing pixels of a display, and further, the display device can display 3D images with higher resolution.

In a possible implementation manner of the third aspect, the vehicle further includes a first film layer, where the first film layer is formed on any one of the reflective surfaces of the second reflective element, and the first film layer is configured to enhance reflection of polarized light of one or more polarization states by the second reflective element. Through the first film layer, reflection of polarized light in one or more polarization states is enhanced while the road condition in front is not influenced by a driver, so that high-quality 3D images can be received by two eyes of the driver.

In a possible implementation manner of the third aspect, the first film layer includes one or more materials of silver, titanium oxide, silicon monoxide, zinc oxide, and the like.

In a possible implementation manner of the third aspect, the second reflecting element in the vehicle includes a front windshield that reflects the first polarized light and the second polarized light to a left eye and a right eye of the observer, respectively.

In one possible implementation of the third aspect, a front windshield in a vehicle includes a first glass layer proximate to a cockpit and a second glass layer distal from the cockpit; the vehicle further includes a second film layer positioned between the first glass layer and the second glass layer, the second film layer being configured to refract light reflected by a surface of the second glass layer such that the light reflected by the surface of the second glass layer is different from a propagation direction of the light reflected by the first glass layer. In this way, it is avoided that the light reflected by the surface of the second glass layer is received by the driver, so that the driver can only receive the light reflected by the surface of the first glass layer, thereby avoiding the formation of ghost images.

The technical effects caused by any one of the design manners of the second aspect to the third aspect may be referred to the technical effects caused by the different design manners of the first aspect, and will not be described herein.

Drawings

FIG. 1 is a schematic diagram of an exemplary light barrier stereoscopic display technique implementation;

FIG. 2 is a schematic diagram of an exemplary lenticular stereoscopic display technique implementation;

fig. 3a is a schematic view of an application scenario of the projection apparatus provided in the present application;

fig. 3b is a schematic view of another application scenario of the projection apparatus provided in the present application;

fig. 3c is a schematic view of another application scenario of the projection apparatus provided in the present application;

fig. 3d is a schematic view of another application scenario of the projection apparatus provided in the present application;

fig. 4 is a schematic structural diagram of a projection device according to an embodiment of the present application;

fig. 5a is a schematic structural diagram of a projection device including a projection unit according to an embodiment of the present application;

FIG. 5b is a schematic view of another projection device including a projection unit according to an embodiment of the present disclosure;

FIG. 5c is a schematic view of a projection unit according to an embodiment of the present disclosure;

FIG. 6a is a schematic view of a projection device including a diffuser screen according to an embodiment of the present application;

FIG. 6b is a schematic view of another projection device including a diffuser screen according to an embodiment of the present application;

FIG. 7 is a schematic view of a diffusion angle of a diffusion screen according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a projection apparatus including a reflective element according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of a display module according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of another display module according to an embodiment of the present application;

FIG. 11 is a schematic diagram of several spectroscopic units according to an embodiment of the present application;

fig. 12 is a schematic view of an optical path when the light splitting unit is a wollaston prism according to an embodiment of the present application;

FIG. 13 is a schematic diagram of another spectroscopic unit according to an embodiment of the present application;

FIG. 14 is a schematic diagram showing the dispersion of calcite and α -BBO in refractive light (o-light and e-light) according to the examples of the present application;

fig. 15 is a schematic view of a display device according to an embodiment of the present application;

FIG. 16 is a schematic illustration of the application of the projection device of the present application to a head-up display device HUD of a vehicle;

FIG. 17 is a schematic view of a reflective element in a vehicle according to an embodiment of the present application;

Fig. 18 is a schematic diagram of one possible functional framework of a vehicle according to an embodiment of the present application.

Detailed Description

Before describing embodiments that are related to the present application, some technical terms related to the embodiments of the present application are described.

Polarization of light: the light wave is an electromagnetic wave, the electromagnetic wave is a transverse wave, and the transverse wave has polarization. The phenomenon that the spatial distribution of the vibration direction of the vibration vector of the light wave loses symmetry with respect to the propagation direction of the light, that is, the phenomenon that the vibration vector of the transverse wave (perpendicular to the propagation direction of the wave) deviates in some direction is called the polarization phenomenon of the light.

Unpolarized light: the orientation of the vibration vector of the light wave in each possible direction is uniform in a plane perpendicular to the propagation direction of the light wave, the magnitude and direction of the vibration vector having irregular variations, such light being referred to as natural light, also referred to as unpolarized light.

Plane polarized light or linearly polarized light: the plane formed by the vibration direction of the vibration vector of the light wave and the propagation direction of the light wave is called a vibration plane. The vibration plane is limited to a certain fixed direction light, and is plane polarized light or linear polarized light.

Polarization direction of light: i.e. the direction of vibration of the vibration vector of the light wave.

P-polarized light and S-polarized light: when light rays penetrate the surface of an optical element (e.g., a beam splitter) at non-perpendicular angles, both reflection and transmission characteristics depend on polarization. In this case, a plane is defined that contains the incident and reflected beams, and is called p-polarization if the vibration vector of the light is in this plane, and s-polarization if the vibration vector is perpendicular to this plane. Either polarization state can be expressed as a vector sum of s-component and p-component.

Birefringence (birefringence): refers to the phenomenon that an incident light ray is decomposed into two polarized lights with mutually perpendicular vibration directions, different propagation speeds and different refractive indexes. Wherein the generation of a refracted ray follows the law of refraction, called the light of the ordinary (o-ray for short); the generation of another refracted ray does not follow the law of refraction and is called extraordinary light (extraordinary light, e light for short).

Birefringent material: including crystalline and amorphous materials, refers to materials that are capable of causing birefringence in incident light. Wherein the birefringent crystal material includes but is not limited to quartz, calcite, lithium niobate, lithium tantalate, etc., and the birefringent amorphous material includes plastic, epoxy resin, etc.

Permanent birefringence: anisotropic transparent crystals, such as calcite, quartz, etc., are an inherent property, and the birefringence effect of such crystals is called permanent birefringence.

Temporary birefringence or artificial birefringence: the birefringence of some materials exists under certain conditions. For example, glass, plastic, epoxy, etc. are generally not birefringent, but are birefringent when they are internally stressed. For another example, materials such as nitrobenzene and barium titanate may exhibit birefringence under the influence of an electric field, which is referred to as temporary birefringence or artificial birefringence.

Optical axis (optical axis) of birefringent crystal: there is a special direction in the birefringent crystal, when light propagates along this direction, no birefringence occurs, this direction is the direction of the optical axis of the birefringent crystal, and all straight paths parallel to the direction of the optical axis in the birefringent crystal are the optical axes of the birefringent crystal.

The spectroscopic stereo display technology refers to that based on the binocular vision difference of an observer, two slightly different images which can be seen by the left eye and the right eye of the observer are displayed in a plane, so that the observer can generate the visual effect of watching a three-dimensional stereo image (hereinafter referred to as a 3D image for short), and things in the 3D image can be protruded out of a picture or can be deeply hidden in the picture.

The light-splitting stereo display technology mainly comprises a light barrier type stereo display technology and a micro-column lens type stereo display technology. However, both of these spectroscopic stereoscopic display techniques lose resolution of the image, affecting image quality.

Fig. 1 is a schematic diagram of an exemplary light-barrier stereoscopic display technology implementation. As shown in fig. 1, the display 101 includes two types of pixel points, respectively denoted as VaR and VaL, where VaR is used to emit light carrying right-eye image information (hereinafter, referred to as right-eye light), and VaL is used to emit light carrying left-eye image information (hereinafter, referred to as left-eye light). The parallax barrier structure 102 is positioned on the light exit side of the display 101, and when it is in a desired position relative to the display 101 and relative to the eyes of the observer, it may allow the right eye of the observer to receive almost only the right eye light emitted by the VaR, and allow the left eye of the observer to receive almost only the left eye light emitted by the VaL. In this way, the left eye and the right eye of the observer can respectively see different images, so that the observer can generate a visual effect of watching the 3D image. As can be seen from fig. 1, since only a part of the pixels of the display 101 are used for emitting left eye light and only another part of the pixels are used for emitting right eye light, the resolution of the image that can be seen by the viewer is low.

Fig. 2 is a schematic diagram of an exemplary lenticular stereoscopic display technique implementation. As shown in fig. 2, similar to the principle of implementation of the light-barrier stereoscopic display technique shown in fig. 1, the pixels of the display 101 are divided into two types (not shown in fig. 2), one for emitting left eye light and the other for emitting right eye light. Unlike the light barrier stereoscopic display technology shown in fig. 1, which is implemented by the principle that the light-emitting side of the display 101 is provided with the lenticular lens 103, the left eye light emitted from the display 101 is refracted in one direction when passing through the lenticular lens 103 and is finally received by the left eye of the observer, and the left eye light emitted from the display 101 is refracted in the other direction when passing through the lenticular lens 103 and is finally received by the right eye of the observer. In this way, the left eye and the right eye of the observer can respectively see different images, so that the observer can generate a visual effect of watching the 3D image. As can be seen from fig. 2, since only a part of the pixels of the display 101 are used to emit left eye light, only another part of the pixels should emit right eye light, resulting in a lower resolution of the image that can be seen by the viewer.

In order to be able to present high resolution 3D images, the present application provides a projection device that can be applied in video entertainment and driving-assisted scenes. In specific application, the projection device can be used alone or can be integrated into other devices as a component.

For example, in some possible application scenarios, the projection device of the present application may be a projector, and referring to fig. 3a, the projector may project an image onto a wall surface or a projection screen.

In other possible application scenarios, the projection apparatus in the present application may be integrated into a Near Eye Display (NED) device, which may be, for example, an augmented reality (augmented reality, AR) device or a Virtual Reality (VR) device, which may include, but is not limited to, AR glasses or AR helmets, and a VR device, which may include, but is not limited to, VR glasses or VR helmets. Referring to fig. 3b, taking NED devices as VR glasses as an example, a user may wear VR glasses to play games, watch videos, participate in virtual meetings, or video shopping, etc.

In yet other possible application scenarios, the projection device in the present application may be integrated in a HUD. Referring to fig. 3c, taking the HUD installed in a vehicle as an example, the HUD may project navigation information, instrument information, etc. in a front view range of a driver, so as to avoid the driver from looking at the information with low head, thereby affecting driving safety. The HUD projected image forms a virtual image outside the vehicle after reflection off the windshield. Types of HUDs include, but are not limited to, windshield (W) -HUD, augmented reality head up display (AR-HUD), and the like.

In still other possible application scenarios, the projection device in the present application may also be integrated in a vehicle-mounted display screen, where the vehicle-mounted display screen may be mounted at a seat back or a co-driver position of a vehicle, and the location where the vehicle-mounted display screen is mounted is not limited in the present application.

In yet another possible application scenario, the projection device of the present application may also be integrated in a vehicle lamp. Referring to fig. 3d, besides the lighting function, the vehicle lamp can also realize an adaptive high beam system (adaptive driving beam, ADB), can project more complex graphics such as characters or traffic signs, and can also project pictures such as videos, thereby increasing the functions of assisting driving or entertainment.

It should be noted that the above application scenario is merely an example, and the projection apparatus provided in the present application may also be applied to other possible scenarios, such as medical equipment, which is not limited in the present application.

Fig. 4 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application. As shown in fig. 4, the projection apparatus 400 includes a display module 401 and a light splitting unit 402.

With continued reference to fig. 4, the display module 401 is configured to generate a first light beam P1 and emit the first light beam P1 to the beam splitting unit 402. The first light beam P1 includes a first polarized light P11 carrying first image information, and a second polarized light P12 carrying second image information. The first polarized light P11 may be linearly polarized light in the P-state (or linearly polarized light in the S-state), and the second polarized light P12 may be linearly polarized light in the S-state (or linearly polarized light in the P-state), that is, the first polarized light P11 is perpendicular to the polarization direction of the second polarized light P12. The first image information may be image information desired to be presented to the left eye of the observer, that is, left eye image information, and the second image information may be image information desired to be presented to the right eye of the observer, that is, right eye image information.

In one possible implementation, in the first light beam P1, the first polarized light P11 and the second polarized light P12 coexist. Alternatively, the display module 401 may generate the first polarized light P11 and the second polarized light P12 simultaneously. It should be understood that "simultaneous" herein may have an absolute meaning, i.e. referring to the same instant, or a relative meaning, i.e. meaning that the time difference between the two instants is sufficiently close. In this implementation, the first light beam P1 is a light beam obtained by combining the first polarized light P11 and the second polarized light P12. In the example of the projection apparatus 400 shown in fig. 4, the first polarized light P11 and the second polarized light P12 in the first light beam P1 generated by the display module 401 coexist. A possible structure of such a display module 401 will be described in detail in the following embodiments.

In another possible implementation, in the first light beam P1, the first polarized light P11 and the second polarized light P12 exist separately. Specifically, the display module 401 sequentially generates the first polarized light P11, the second polarized light P12, the first polarized light P11, and the second polarized light P12 … … at different timings according to a certain timing rule. For example, the first polarized light P11 is generated at each first preset time, the second polarized light P12 is generated at each second preset time, and a second preset time exists between every two adjacent first preset times, or a first preset time exists between every two adjacent second preset times. In this implementation, the display module 401 generates the first light beam P1 as the first polarized light P11 at each first preset time, and generates the first light beam P1 as the second polarized light P12 at each second preset time. A possible structure of the display module 401 will be described in detail in the following embodiments. With continued reference to fig. 4, the light splitting unit 402 is located on the light emitting side of the display module 401, that is, on the propagation path of the first light beam P1. Thus, the first light beam P1 emitted from the display module 401 can be transmitted to the beam splitting unit 402. The light splitting unit 402 is configured to make the first polarized light P11 and/or the second polarized light P12 in the first light beam P1 emit in different directions by making the first light beam P1 birefringent, and further propagate in different directions, respectively.

In the introductory part of the term of the present application, the meaning of birefringence has been explained. The birefringence effect of the light splitting unit 402 is further explained herein with reference to fig. 4: after the first light beam P1 propagates to the light splitting unit 402, two beams of refraction light are generated under the action of the light splitting unit 402, and the two beams of refraction light are the first polarized light P11 and the second polarized light P12. Since the two light beams generated by the birefringence do not affect each other, in the implementation in which the first polarized light P11 and the second polarized light P12 exist separately in the first light beam P1, the birefringence of the light splitting unit 402 can be understood as that, in the case where the first light beam P1 is the first polarized light P11, after propagating to the light splitting unit 402, the first light beam P1 is refracted at the first refractive index under the action of the light splitting unit 402; in the case that the first light beam P1 is the second polarized light beam P12, after propagating to the light splitting unit 402, it is refracted at the second refractive index under the action of the light splitting unit 402; the first refractive index is different from the second refractive index.

The birefringence action performed by the spectroscopic unit 402 may be permanent birefringence or temporary birefringence. When it is designed to be temporarily birefringent, a condition triggering means may be designed, by which conditions necessary for generating the temporary birefringence are provided, for example, by applying an electric field by an electric field applying means or the like, depending on the specific structure of the spectroscopic unit and the birefringent material employed.

As can be seen from the above, in the implementation in which the first light beam P1 includes both the first polarized light beam P11 and the second polarized light beam P12, the birefringent effect of the light splitting unit 402 may separate the first polarized light beam P11 and the second polarized light beam P12 at a certain angle, and further, the first polarized light beam P11 and the second polarized light beam P12 may continuously propagate along different directions. In the implementation manner in which the first light beam P1 includes the first polarized light beam P11 or the second polarized light beam P12 alone, for the first polarized light beam P11 and the second polarized light beam P12 having the same original propagation direction, the birefringence effect of the light splitting unit 402 may change the propagation directions of the first polarized light beam P11 and the second polarized light beam P12 into different directions, so that the two light beams may continue to propagate along different directions. Because the first polarized light P11 carries left eye image information, it can be used to image a left eye image, and the second polarized light P12 carries right eye image information, it can be used to image a right eye image, and because the propagation directions of the first polarized light P11 and the second polarized light P12 are different, the imaging positions of the right eye image and the right eye image are different, when the two images are respectively received by the left eye and the right eye of the observer, the observer can generate the visual experience of the 3D image.

Based on the projection apparatus 400 shown in fig. 4 and the description of the projection apparatus 400, the display module 401 in the projection apparatus 400 can generate a first light beam including a first polarized light and a second polarized light, where the first polarized light and the second polarized light respectively carry different image information, and the light splitting unit 402 in the projection apparatus 400 has a double refraction effect and can emit the first polarized light and the second polarized light in the first light beam in different directions, so that the first polarized light and the second polarized light can continue to propagate along different directions. The realization principle can be known, the aim of light splitting three-dimensional display can be achieved without dividing pixels of a display, and further, the projection device can project images with higher resolution.

Based on the above embodiments, the projection device provided in the present application may further include a projection unit, for example, a projection lens group, which may be a short-focal lens group or a long-focal lens group. It should be understood that, in the above-mentioned projection apparatus 400, the light beam (such as the first light beam) emitted by the display module 401 includes uniform light emitted by all pixels in the display module 401, and such light beam, although carrying image information, cannot display a corresponding image frame. Based on this, the projection lens group functions to converge a light beam containing image information (such as the first light beam described above) into a light beam capable of imaging (hereinafter simply referred to as an imaging light beam) and project it outward.

Referring to fig. 5a, the projection unit 403 may be located on a propagation path of the first light beam P1 between the display module 401 and the beam splitting unit 402. In this way, the projection unit 403 may converge the first light beam P1 to obtain an imaging light beam P1', and project the imaging light beam P1' to the spectroscopic unit 402. It should be appreciated that the imaging light beam P1 'still comprises polarized light carrying left eye image information and polarized light carrying right eye image information, more precisely the imaging light beam P1' comprises first polarized imaging light P11 'carrying left eye image information and second polarized imaging light P12' carrying right eye image information. Note that the meaning of polarized light and polarized imaging light is distinguished here in that polarized imaging light can be directly imaged. It should be understood that in this implementation, the display module 401 and the projection unit 403 form an image source of the projection apparatus 400.

Referring to fig. 5b, the projection unit 403 may also be located on the propagation path of the first polarized light P11 and the second polarized light P12 after passing through the light splitting unit 402, i.e. on the light emitting side of the light splitting unit 402, i.e. on the side of the light splitting unit 402 away from the display module 401. In this way, the projection unit 403 may converge the first polarized light P11 and the second polarized light P12 emitted from the light splitting unit 402, respectively, so that the first polarized light P11 and the second polarized light P12 become light beams capable of imaging, that is, the first polarized imaging light P11 'and the second polarized imaging light P12'. It should be understood that in this implementation, the display module 401, the light splitting unit 402, and the projection unit 403 constitute an image source of the projection apparatus 400.

For the projection apparatus shown in fig. 5b described above, the projection unit 403 may include two projection lens groups 4031 and 4032 as shown in fig. 5 c. The projection lens group 4031 is located on the propagation path of the first polarized light P11, and is configured to converge the first polarized light P11 to project the first polarized imaging light P11'. The projection lens group 4032 is located on the propagation path of the second polarized light P12 and is used for converging the second polarized light P12 to project the second polarized imaging light P12'. As can also be seen from fig. 5c, each projection lens group comprises three optical lenses. It should be appreciated that in other implementations, the projection lens group may include more or fewer optical lenses, and is not limited to the three shown in fig. 5 c.

In order to improve uniformity of an imaging picture, the projection device provided by the application can further comprise a light diffusion element. The light diffusing element may also be referred to as a diffuser screen. The diffuser screen may be located on the light exit side of the light splitting unit 402. However, in the case where the projection apparatus 400 includes the above-described projection unit 403, there are a plurality of possible implementations of the relative positional relationship of the diffusion screen and the projection unit 403.

Referring to fig. 6a, a diffusion screen 404 may be located between the beam splitting unit 402 and the projection unit 403. In this way, the diffusion screen 404 may be used to diffuse the first polarized light P11 and the second polarized light P12, and the diffused first polarized light P11 and second polarized light P12 are converged by the projection unit 403 to form the first polarized imaging light P11 'and the second polarized imaging light P12', so as to improve the uniformity of the imaging frames of the first polarized imaging light P11 'and the second polarized imaging light P12'.

Referring to fig. 6b, the projection unit 403 is located on a propagation path of the first light beam P1 between the display module 401 and the beam splitting unit 402. The diffusion screen 404 is located on the light-emitting side of the light-splitting unit 402. In this way, the diffusion screen 404 can directly diffuse the first polarized imaging light P11 'and the second polarized imaging light P12' emitted from the light splitting unit 402, so as to improve the uniformity of the imaging frames of the first polarized imaging light P11 'and the second polarized imaging light P12'.

Referring to fig. 7, a diffusion angle α of the diffusion screen is shown in fig. 7. In a possible implementation, the diffusion angle α of the diffusion screen 404 is less than 20 °. In this way, crosstalk between two light beams caused by excessive diffusion of the first polarized light (or the first polarized imaging light) and the second polarized light (or the second polarized imaging light) can be avoided, and the imaging effect is ensured.

The projection device provided in the embodiment of the application may further include a reflective element. In order to distinguish from the reflective element in the vehicle appearing hereinafter, the reflective element included in the projection device is referred to as a first reflective element in the embodiments of the present application. Illustratively, the first reflective element is a projection window, a projection lens, or a projection curtain. The first reflecting element is for reflecting the first polarized imaging light P11 'and the second polarized imaging light P12'.

It should be noted that, the first reflecting element may be integrated with the display module 401, the light splitting unit 402, the projection unit 403, and the diffusion screen 404, or may be independent of the display module 401, the light splitting unit 402, the projection unit 403, and the diffusion screen 404. For example, when the projection device is integrated with the VR glasses, the first reflective element may be a projection lens, and the projection lens, the display module 401, the light splitting unit 402, the projection unit 403 and the diffusion screen 404 are integrated together in the VR glasses. When the projection device is a projector, the first reflective element may be a projection curtain, which is independent of the display module 401, the light splitting unit 402, the projection unit 403 and the diffusion screen 404.

It should be understood that, as shown in fig. 8, when the first reflecting element 405 is integrated with the display module 401, the light splitting unit 402, the projection unit 403, and the diffusion screen 404, the first reflecting element is located on the propagation path of the first polarized imaging light P11 'and the second polarized imaging light P12'. In this way, the first polarized imaging light P11 'and the second polarized imaging light P12' may be directly irradiated onto the first reflecting element and reflected by the first reflecting element. When the first reflecting element is independent of the display module 401, the light splitting unit 402, the projection unit 403 and the diffusion screen 404, the setting position of the reflecting element depends on the installation environment and is not limited in this application.

With respect to the projection apparatus 400 according to the above embodiment, a description will be given below of possible configurations of the display module 401 and the spectroscopic unit 402 in the projection apparatus 400 in order.

Referring to fig. 9, in one possible implementation, the display module 401 may include a light source 901, a polarization beam splitter 902, a first modulator 903 and a second modulator 904.

Wherein, the light source 901 is used for transmitting the second light beam P2 to the polarization beam splitter prism 902. The second light beam P2 may be unpolarized light, or may be a light beam obtained by combining S-polarized light and P-polarized light. Here, the light source 901 may include a light emitting source and a plurality of polarizers, and the unpolarized light emitted from the light emitting source may be polarized in S-state and P-state after passing through the corresponding polarizers. In a possible implementation, a collimating lens 904 is further included for focusing and collimating the light emitted by the light source 901.

The polarization splitting prism 902 has four sides, i.e., S1, S2, S3, and S4 shown in fig. 9. The first modulator 903 is disposed opposite to S2 of the polarization beam splitter prism 902, and the second modulator 904 is disposed opposite to S3 of the polarization beam splitter prism 902. The polarization splitting prism 902 further has a light splitting surface S0, and the light splitting surface S0 can reflect S-state polarized light and transmit P-state polarized light. Based on this, the polarizing beam splitter prism 902 functions to reflect S-polarized light and transmit P-polarized light from the beam splitting surface S0 when the second light beam P2 propagates to the beam splitting surface S0 through S1. The S-polarized light it reflects will pass S2 to the first modulator 903 and be received by the first modulator 903. The P-state polarized light transmitted by it will pass through S3 to the second modulator 904 and be received by the second modulator 904.

The first modulator 903 is configured to modulate S-polarized light into the first polarized light P11 according to an input electrical signal including left-eye image data. The first polarized light P11 here is P-state polarized light. The first modulator 903 emits the first polarized light P11 in the P state, and the first polarized light P11 reaches S0 through S2, is transmitted from S0 to S4, and is emitted from S4.

The second modulator 904 is configured to modulate the P-polarized light into the second polarized light P12 according to the input electric signal including the right-eye image data. The second polarized light P12 here is S-state polarized light. The second modulator 904 emits the second polarized light P12 in the S state, and the second polarized light P12 reaches S0 through S3, is reflected by S0 to S4, and is emitted from S4.

It can be seen that the first polarized light P11 generated by the first modulator 903 and the second polarized light P12 generated by the second modulator 904 are combined into a first light beam P1 by the polarization splitting prism 902. The S4 side of the polarization beam splitter prism 902 is the light-emitting side of the display module 401, and the first light beam P1 is emitted to the beam splitter unit 402 from the light-emitting side. In the above-described implementation, the first polarized light P11 and the second polarized light P12 coexist in the first light beam P1 generated by the display module 401. Alternatively, the display module 401 may generate the first polarized light P11 and the second polarized light P12 simultaneously.

The first modulator 903 and the second modulator 904 may be a liquid crystal on silicon (liquid crystal on silicon, LCOS) display or a thin film transistor-liquid crystal display (thin film transistor liquid crystal display, TFT-LCD).

Referring to fig. 10, in another possible implementation, the display module 401 may include: a light source 1001, a polarizer 1002, a modulator 1003, and a polarization converter 1004. The light source 1001 is configured to emit a second light beam P2, where the second light beam P2 may be white light. A polarizer 1002, a modulator 1003, and a polarization converter 1004 are sequentially located on the propagation path of the second light beam P2.

The second light beam P2 first irradiates the polarizer 1002. The polarizer 1002 is used to obtain linearly polarized light from the second light beam P2, and emits it to the modulator 1003. The linearly polarized light may be S-polarized light or P-polarized light. The modulator 1003 is configured to modulate the linear polarized light into first polarized light P11 having a certain polarization state and including left-eye image information according to an input electric signal including left-eye image data at each first preset time, and modulate the linear polarized light into third polarized light P13 having the same polarization state as the first polarized light P11 but including right-eye image information according to an input electric signal including right-eye image data at each second preset time. Meanwhile, the modulator 1003 transmits the first polarized light P11 and the third polarized light P13 generated thereby to the polarization converter 1004. The polarization converter 1004 is configured to directly emit the first polarized light P11 to the light splitting unit 402 when receiving the first polarized light P11, and to convert the third polarized light P13 in the P state (or S state) into the second polarized light P12 in the S state (or P state) by phase conversion when receiving the third polarized light P13, and to emit the second polarized light P12 to the light splitting unit 402.

In the above implementation manner, a second preset time exists between every two adjacent first preset times, or, a first preset time exists between every two adjacent second preset times. It should be noted that, for a group of left eye image and right eye image, when the time difference between the left eye image received by the left eye and the right eye image received by the right eye of the observer is less than a certain threshold, the observer's brain cannot perceive the time difference, that is, the time difference between the left eye image light projected by the projection device and the right eye image light projected by the projection device is less than the threshold, the visual effect of the observer, for example, the feeling of jamming or confusion, will not be affected. Based on this, in the above implementation, the time difference between the adjacent first preset time and second preset time needs to be smaller than the aforementioned threshold, i.e. the resolution of the brain for the above-mentioned reception time difference is satisfied.

It should be noted that the third polarized light P13 is the same as the polarized direction (i.e., the polarized state) of the first polarized light P11, but is different from the image information included in the first polarized light P11. For example, in the case where the linearly polarized light emitted from the polarizer 1002 is P-state polarized light, the modulator 1003 may generate P-state first polarized light P11 at each first preset time, and the P-state first polarized light P11 may include left-eye image information. Third polarized light P13 in a P state is generated at each second preset time, and the third polarized light P13 in the P state may include right eye image information. In the case where the linearly polarized light emitted from the polarizer 1002 is S-state polarized light, the modulator 1003 may generate S-state first polarized light P11 at each first preset time, and the S-state first polarized light P11 may include left-eye image information. Third polarized light P13 in S state is generated at each second preset time, and the third polarized light P13 in S state may contain right eye image information.

In the above implementation manner, in the first light beam P1 generated by the display module 401, the first polarized light P11 and the second polarized light P12 exist separately. Specifically, the first light beam P1 generated by the display module 401 at each first preset time is the first polarized light P11, and the first light beam P1 generated at each third preset time is the second polarized light. Wherein each third preset time corresponds to a second preset time. The third preset time may be understood as a time when the polarization converter 1004 converts the third polarized light P13 into the second polarized light P12.

The modulator 1003 may be a digital light processing (digital light processing, DLP) display.

Referring to fig. 11, fig. 11 shows a schematic diagram of several possible optical splitting units 402. In each of the possible structural designs, the light splitting unit 402 includes two right angle prisms, namely, a first right angle prism 1101 and a second right angle prism 1102, where the largest side of the first right angle prism 1101 (the side on which the hypotenuse is located) is bonded to the largest side of the second right angle prism 1102 (the side on which the hypotenuse is located). It is noted that the first right angle prism 1101 and the second right angle prism 1102 are made of birefringent crystal material.

As can be seen from the foregoing, the light splitting unit 402 may be a prism made of a birefringent crystal material, including, but not limited to, a gram-foucault prism (Glan Foucault prism), a Wollaston prism (Wollaston prism), a Rochon prism (Rochon prism), and a senarmon prism (senarmon prism), which are shown in fig. 11. Fig. 11 also shows the optical path of the first light beam P1 as it passes through each prism. The two refractive light beams generated by the first light beam P1 in the prism are the first polarized light beam P11 and the second polarized light beam P12, or the first polarized imaging light beam P11 'and the second polarized imaging light beam P12', respectively. One of the refracted rays is o light (or e light), and the other refracted ray is e light (or o light).

The Wollaston prism and the optical path of the light beam in the Wollaston prism will be described below taking the example in which the beam splitting unit 402 is the Wollaston prism shown in FIG. 11.

Referring to fig. 12, the wollaston prism is composed of a first right angle prism 1101 and a second right angle prism 1102, the maximum sides (BD faces) of which are bonded by glycerin or castor oil, and the two right angle prisms are processed by calcite. The optical axis direction of the rectangular prism is described in terms of coordinate axes in a space rectangular coordinate system, wherein the optical axis direction Z of the first rectangular prism is perpendicular to the optical axis direction Y of the second rectangular prism. When the wollaston prism is integrated into the projection apparatus 400 as the beam splitting unit 402, the first right angle prism 1101 and the second right angle prism 1102 are sequentially arranged along the propagation direction of the first light beam P1, such that the AB plane of the first right angle prism 1101 is perpendicular to the propagation direction of the first light beam P1, and correspondingly, the CD plane of the second right angle prism 1102 is also perpendicular to the propagation direction of the first light beam P1. In this way, the first light beam P1 will be incident into the wollaston prism in a direction perpendicular to the AB plane. In this example, the first polarized light P11 and the second polarized light P12 coexist in the first light beam P1.

When the first light beam P1 perpendicularly enters the AB surface, refraction angles of the first polarized light P11 and the second polarized light P12 are both 0, that is, the two light beams continue to propagate in the same direction without refraction but at different speeds Vo and Ve, respectively. One of the first polarized light P11 and the second polarized light P12 is o light, and the other is e light. The following description will proceed with an example in which the first polarized light is o light and the second polarized light is e light. When they enter the second right angle prism 1102 in sequence, since the optical axis of the second right angle prism 1102 is perpendicular to the optical axis of the first right angle prism, the o-light (i.e., the first polarized light P11) in the first right angle prism 1101 becomes e-light to the second right angle prism, and the e-light (i.e., the second polarized light P12) becomes o-light. Therefore, the first polarized light P11 is refracted at the boundary BD surface of the two right angle prisms with the relative refractive index ne/no, and the second polarized light P12 is refracted at the relative refractive index no/ne. Where no denotes the refractive index of o light in the prism material, and ne denotes the refractive index of e light in the prism material. In the case where the prism material is a negative crystal of no > ne (e.g., calcite), the e light in the second right angle prism 1102, i.e., the first polarized light P11, will propagate in a direction away from the normal to the BD surface, and the o light in the second right angle prism 1102, i.e., the second polarized light P12, will propagate in a direction closer to the normal to the BD surface, with the two light beams being separated in the second right angle prism 1102. The two light beams are then refracted again as they pass through the CD surface of the second right angle prism 1102, and finally two polarized light beams separated by a certain angle are emitted from the wollaston prism.

As can be seen from the above, the wollaston prism can make the incident first light beam P1 have double refraction, and further make the first polarized light P11 and the second polarized light P12 included in the incident first light beam separate by a certain angle, and finally, the incident first light beam and the incident second light beam are emitted from the wollaston prism in different directions. Also, when the right angle prism apex angle (i.e., 1 shown in fig. 12) is a certain reasonable angle, the emission directions of the first polarized light P11 and the second polarized light P12 can be made symmetrical with respect to the normal line of the CD plane, i.e., the first polarized light P11 and the second polarized light P12 can be made almost symmetrically separated.

Wherein the angle between the first polarized light P11 and the second polarized light P12Can be approximated as It should be understood that, the angle 1=90° -incidence angle, which is the incidence angle when the first polarized light P11 and the second polarized light P12 are incident on the second right angle prism 1102.

It should be understood that the optical paths of the light beams in different types of prisms are related to factors such as the propagation direction and polarization state of the light beams, the optical axes of the two right angle prisms, the apex angle of the right angle prisms, and ne and no thereof. Thus, the light beam, comprising the first light beam and the separate first and second polarized light, is different in the light paths in the above-mentioned gram-fourier prism, wollaston prism, rochon prism and saicing prism. When designing the projection device, a person skilled in the art may first design the optical path of the light beam according to the requirement, and then design the beam splitting unit 402 according to the designed optical path. The projection device spectroscopic unit 402 of the present application is not limited to the rectangular prism having the above-described structure, but is not limited to a system in which two rectangular prisms are combined. That is, the manner of designing the spectroscopic unit 402 using the birefringent crystal material is not limited in this application.

Referring to fig. 13, another possible optical splitting unit 402 is shown. In some embodiments, the light splitting unit 402 includes multiple sets of first right angle prisms and second right angle prisms as described above, such as the three sets shown in the figures. The right angle prisms can be integrally formed or independent. In each group of right-angle prisms, the included angle between the AB surface of the first right-angle prism and the propagation direction of the light ray in the first light beam P1 incident therein is the same.

Regarding the arrangement of the plurality of sets of right angle prisms in fig. 13, it can be understood that the first light beam P1 emitted by the display module 401 includes a plurality of light beams, and the plurality of light beams are not absolutely parallel. When there is only one first right angle prism, the angles of the different light rays when they are incident on the AB-plane are not absolutely identical. For example, if it is desired that the first light beam P1 is incident on the first right angle prism at an angle perpendicular to the AB plane, a substantial portion of the light is not actually incident in a direction perpendicular to the AB plane. When different light rays are incident to the first right-angle prism at different angles, the included angles between the first polarized light and the second polarized light which are emitted from the second right-angle prism and correspond to the different light rays are different. Thus, crosstalk is likely to occur between the first polarized light and the second polarized light, and the imaging quality of the projected image is affected. Based on this, through adopting multiunit right angle prism to the position of every group right angle prism is designed, makes in every group right angle prism, and the contained angle between the AB face of first right angle prism all and the propagation direction of the light in the first light beam of incidence wherein all or most light can all be in the first right angle prism with the same angle incidence in the first light beam, and then guarantees the contained angle between the first polarized light and the second polarized light of following the ejection of every second right angle prism and being as same as possible. In this way, crosstalk between the first polarized light and the second polarized light can be avoided, and the imaging quality of the projection image is improved.

The property of a material that its refractive index decreases with decreasing frequency (or increasing wavelength) of the incident light is called "chromatic dispersion". For example, a fine beam of sunlight may be split by a prism into red, orange, yellow, green, blue, indigo, violet and seven colors. This is because the refractive indices of the respective color lights in the polychromatic light are different. As they pass through the prism, the propagation directions are deflected to different extents and thus each diverge as they leave the prism. It will be readily appreciated that the dispersive action of the prismatic material on the first light beam, or the first and second polarized light separated from the first light beam, will affect the imaging quality of the projected image.

To reduce or avoid dispersion of the beam by the prism material, in some embodiments, the birefringent crystal material used by the beam splitting unit 402 is barium metaborate (α -BBO). Compared with other birefringent crystal materials such as calcite, the alpha-BBO material can reduce the dispersion of the prism on light, so that the imaging quality of a projection image is ensured.

Fig. 14 a and b are diagrams showing the dispersion phenomena caused by calcite and α -BBO on refracted rays (o-ray and e-ray), respectively. Wherein the abscissa represents the wavelength of the refracted ray, the ordinate represents the deviation of the refraction angles of the o-ray and the e-ray, that is, the deviation of the actual refraction angles of the o-ray and the e-ray from the ideal refraction angle when no chromatic dispersion occurs, for example, the ordinate is 0, and the deviation of the actual refraction angles of the o-ray and the e-ray from the ideal refraction angle is 0. As can be seen from fig. 14 a and b, when calcite is used as the light propagation medium, the refractive angle deviation of o light and e light is large in the wavelength range of 0.4um to 0.7 um. The refractive angle deviation of o-light and e-light is significantly reduced when α -BBO is used as a light propagation medium, relative to calcite. Therefore, the alpha-BBO can reduce the chromatic dispersion of the prism on light rays, and further ensure the imaging quality of the projection image.

The embodiment of the application also provides a display device, which can be a projection display device used in occasions such as families, classrooms, meeting rooms, auditoriums, cinema, courts, squares and the like, can be a vehicle-mounted display screen or a display screen integrated in intelligent household appliances and the like, and can be a network television, an intelligent television, an Internet Protocol Television (IPTV) or integrated in the display device. Referring to fig. 15, fig. 15 is a schematic view of a display device according to an embodiment of the present application.

As shown in fig. 15, the circuits in the display device mainly include a processor 1501, an internal memory 1502, an external memory interface 1503, an audio module 1504, a video module 1505, a power module 1506, a wireless communication module 1507, an i/O interface 1508, a video interface 1509, a controller area network (Controller Area Network, CAN) transceiver 1510, a display circuit 1511, any one of the above projection apparatuses 400, and the like. The processor 1501 and its peripheral components, such as the internal memory 1502, the can transceiver 1510, the audio module 1504, the video module 1505, the power module 1506, the wireless communication module 1507, the i/O interface 1508, the video interface 1509, the transceiver 1510, and the display circuit 1511 may be connected by buses.

Among other things, the processor 1501 may be referred to as a front-end processor. The processor 1501 includes one or more processing units, such as: the processor 1501 may include an application processor (application processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a controller, a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, and/or a neural network processor (neural-network processing unit, NPU), etc. Wherein the different processing units may be separate devices or may be integrated in one or more processors.

A memory may also be provided in the processor 1501 for storing instructions and data. Such as storing the operating system of the display device, AR Creator software package, etc. In some embodiments, the memory in the processor 1501 is a cache memory. The memory may hold instructions or data that the processor 1501 has just used or is recycled. If the processor 1501 needs to reuse the instruction or data, it may be called directly from the memory. Repeated accesses are avoided and the latency of the processor 1501 is reduced, thus improving the efficiency of the system.

In addition, if the display device in the present embodiment is mounted on a vehicle, the function of the processor 1501 may be implemented by a domain controller on the vehicle.

In some embodiments, the display device may also include a plurality of input/output (I/O) interfaces 1508 coupled to the processor 1501. Interface 1508 may include, but is not limited to, an integrated circuit (inter-integrated circuit, I2C) interface, an integrated circuit built-in audio (inter-integrated circuit sound, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous receiver transmitter (universal asynchronous receiver/transmitter, UART) interface, a mobile industry processor interface (mobile industry processor interface, MIPI), a general-purpose input/output (GPIO) interface, a subscriber identity module (subscriber identity module, SIM) interface, and/or a universal serial bus (universal serial bus, USB) interface, among others. The I/O interface 1508 may be connected to a mouse, a touch screen, a keyboard, a camera, a speaker/speaker, a microphone, etc., or may be connected to physical keys (e.g., a volume key, a brightness adjustment key, an on/off key, etc.) on a display device.

The internal memory 1502 may be used to store computer executable program code including instructions. The memory 1502 may include a stored program area and a stored data area. The storage program area may store an application program (such as a call function, a time setting function, an AR function, etc.) required for at least one function of the operating system, etc. The storage data area may store data created during use of the display device (e.g., phone book, universal time, etc.), etc. In addition, the internal memory 1502 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, universal flash memory (universal flash storage, UFS), and the like. The processor 1501 executes various functional applications of the display device and data processing by executing instructions stored in the internal memory 1502 and/or instructions stored in a memory provided in the processor 1501.

The external memory interface 1503 may be used to connect to an external memory (for example, micro SD card), where the external memory may store data or program instructions as needed, and the processor 1501 may perform operations such as reading and writing on these data or program execution through the external memory interface 1503.

The audio module 1504 is used to convert digital audio information to an analog audio signal output and also to convert an analog audio input to a digital audio signal. The audio module 1504 may also be used to encode and decode audio signals, such as for playback or recording. In some embodiments, the audio module 1504 may be disposed in the processor 1501, or some of the functional modules of the audio module 1504 may be disposed in the processor 1501. The display device may implement audio functionality through the audio module 1504, an application processor, and the like.

The video interface 1509 may receive externally input audio and video, which may specifically be a high-definition multimedia interface (high definition multimedia interface, HDMI), a digital video interface (digital visual interface, DVI), a video graphics array (video graphics array, VGA), a Display Port (DP), a low voltage differential signal (low voltage differential signaling, LVDS) interface, etc., and the video interface 1509 may also output video to the outside. For example, the display device receives video data transmitted from the navigation system or video data transmitted from the domain controller through the video interface.

Video module 1505 may decode video input to video interface 1509, such as h.264 decoding. The video module can also encode the video collected by the display device, for example, H.264 encoding is carried out on the video collected by the external camera. The processor 1501 may decode the video input from the video interface 1509 and output the decoded image signal to the display circuit 1511.

Further, the display device further includes a CAN transceiver 1510, and the CAN transceiver 1510 may be connected to a CAN BUS (CAN BUS) of the automobile. Through the CAN bus, the display device CAN communicate with in-vehicle entertainment systems (music, radio, video modules), vehicle status systems, etc. For example, the user may turn on the in-vehicle music play function by operating the display device. The vehicle status system may send vehicle status information (doors, seat belts, etc.) to a display device for display.

The display circuit 1511 and the projection apparatus realize a function of displaying an image together. The display circuit 1511 receives the image signal output from the processor 1501, processes the image signal, and inputs the processed image signal into a display module of the projection apparatus for imaging. The display circuit 1511 may also control the image displayed by the display module. For example, parameters such as display brightness or contrast are controlled. The display circuit 1511 may include a driving circuit, an image control circuit, and the like.

In this embodiment, the video interface 1509 may receive input video data (or referred to as a video source), the video module 1505 decodes and/or digitizes the input video data, and outputs an image signal to the display circuit 1511, and the display circuit 1511 drives the display module to image a light beam emitted by the light source according to the input image signal, so as to generate a visual image (emit imaging light).

The power module 1506 is configured to provide power to the processor 1501, the projection device, and other devices according to the input power (e.g., dc power), and the power module 1506 may include a rechargeable battery. In addition, the power module 1506 may be coupled to a power module (e.g., a power battery) of the vehicle, which provides power to the power module 1506 of the display device.

The wireless communication module 1507 may enable the display device to wirelessly communicate with the outside world, which may provide solutions for wireless communication such as wireless local area network (wireless local area networks, WLAN), wireless fidelity (wireless fidelity, wi-Fi) network, bluetooth (BT), global navigation satellite system (global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), near field wireless communication technology (near field communication, NFC), infrared technology (IR), and the like. The wireless communication module 1507 may be one or more devices that integrate at least one communication processing module. The wireless communication module 1507 receives electromagnetic waves via an antenna, modulates the electromagnetic wave signals, filters the electromagnetic wave signals, and transmits the processed signals to the processor 1501. The wireless communication module 1507 may also receive signals to be transmitted from the processor 1501, frequency modulate them, amplify them, and convert them to electromagnetic waves for radiation via an antenna.

In addition, the video data decoded by the video module 1505 may be received wirelessly by the wireless communication module 1507 or read from the internal memory 1502 or the external memory, for example, the display device may receive video data from a terminal device or an in-vehicle entertainment system through a wireless lan in the vehicle, and the display device may read audio/video data stored in the internal memory 1502 or the external memory, in addition to the video data input through the video interface 1509.

In addition, the circuit diagrams illustrated in the embodiments of the present application do not constitute a specific limitation on the display device. In other embodiments of the present application, the display device may include more or less components than illustrated, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

The above display device may provide a broadcast receiving television function in addition to the above functions. For example, the display device may be integrated in a web tv, a smart tv, an Internet Protocol Tv (IPTV).

The embodiment of the application also provides a vehicle, which comprises a reflecting element and any one of the projection devices or any one of the display devices. The reflective element is configured to reflect the first polarized imaging light and the second polarized imaging light from the projection device such that the first polarized imaging light is received by a left eye of the observer and the second polarized imaging light is received by a right eye of the observer such that the left eye and the right eye of the observer view slightly different left eye images and right eye images, respectively.

In a possible implementation, the display device described above is integrated in a head-up display HUD of a vehicle. The vehicle may include a reflective element, in particular, a front windshield (i.e., front windshield) thereof.

For example, fig. 16 is a schematic diagram of the projection device according to the present application applied to a head-up display device HUD of a vehicle. As shown in fig. 16, the first polarized imaging light and the second polarized imaging light emitted from the projection device are respectively transmitted to the first free-form surface mirror along different directions, reflected by the first free-form surface mirror to the second free-form surface mirror, emitted by the second free-form surface mirror to the front windshield, and respectively reflected by the front windshield to the left eye and the right eye of the driver, so that a left eye image M1 and a right eye image M2 are formed on one side of the front windshield, and a three-dimensional stereoscopic image is observed by an observer. It should be understood that the left eye image M1 and the right eye image M2 are virtual images. By way of example, the vehicle may be a car, truck, motorcycle, bus, boat, airplane, helicopter, mower, recreational vehicle, casino vehicle, construction equipment, electric car, golf cart, train, trolley, etc., and embodiments of the present application are not particularly limited.

Illustratively, the contents of the left-eye image M1 and the right-eye image M2 include, but are not limited to, map assistance information, indication information of external objects, state information of vehicles, entertainment information, and the like. The map assistance information is used as assistance driving, and includes, for example, but not limited to, a directional arrow, a distance, a travel time, and the like. The indication information of the external object includes, but is not limited to, safe car distance, surrounding obstacle, reversing image and the like. Taking an automobile as an example, the state information of the vehicle is generally information displayed on a vehicle meter, which is also referred to as meter information, including, but not limited to, information of a traveling speed, a traveling mileage, a fuel amount, a water temperature, a lamp state, and the like.

In some embodiments, a first film layer is formed on any one of the reflective surfaces of the front windshield, and the first film layer is used for enhancing reflection of P-polarized light by the front windshield. Thus, the phenomenon of lower reflectivity caused by that the polarization direction of the P-state polarized imaging light is parallel or nearly parallel to the reflecting surface after the P-state polarized imaging light irradiates the front windshield can be avoided. Through the first film layer, reflection of polarized imaging light in the P state is enhanced while the road condition in front is not influenced by a driver, so that high-quality 3D images can be received by two eyes of the driver.

In a possible implementation, the first film layer may include one or more materials of silver, titanium oxide, silicon monoxide, zinc oxide, and the like. Of course, other materials which have better reflection effect on P-state polarized light and have transparency meeting the production requirements of vehicles, which are not listed in the application, can also be adopted, and all belong to the protection scope of the application.

The formation position of the first film layer is not limited in the present application. For example, referring to fig. 17, the front windshield includes a first glass layer and a second glass layer laminated, that is, two surfaces of the first glass layer and two surfaces of the second glass layer are both reflective surfaces of the front windshield. The first film layer may be disposed on any one of the reflective surfaces, such as in fig. 17, the first film layer being disposed on a surface of the first glass layer that is located inside the cockpit.

In some embodiments, a second film layer is disposed between the first glass layer and the second glass layer, and the first film layer is wedge-shaped, so it is also called a wedge-shaped film. The wedge-shaped film is used for refracting the light reflected by the surface of the second glass layer, so that the light reflected by the surface of the second glass layer is different from the light reflected by the first glass layer in propagation direction, and further, the reflected light is prevented from being received by a driver, and ghost images are prevented from being formed.

For example, referring to fig. 17, the first polarized imaging light P11 'and the second polarized imaging light P12' first propagate to the first surface of the front windshield, and most of them can be reflected by the first surface to the eyes of the driver, while the other small part can pass through the first glass layer and the second glass layer, irradiate to the fourth surface, and be reflected by the fourth surface. The wedge-shaped film changes the propagation direction of the reflected light by refracting the light reflected by the fourth surface of the front windshield, so that the propagation direction of the reflected light is different from that of the light reflected by the first surface, and the reflected light is prevented from being received by human eyes. Wherein. The first surface of the front windshield is the surface of the first glass layer, which is positioned in the cockpit, and the fourth surface is the surface of the second glass layer, which is far away from the first glass layer.

Fig. 18 is a schematic diagram of one possible functional framework of a vehicle provided in an embodiment of the present application.

As shown in fig. 18, various subsystems may be included in the functional framework of the vehicle, such as a control system 1801, a sensor system 1802, one or more peripheral devices 1803 (one shown in the illustration), a power supply 1804, a computer system 1805, and a display system 1806, as shown. Alternatively, the vehicle may also include other functional systems, such as an engine system to power the vehicle, etc., as not limited herein.

The sensor system 1802 may include a plurality of sensing devices that sense the measured information and convert the sensed information to an electrical signal or other desired form of information output according to a certain rule. As illustrated, these detection devices may include, without limitation, a global positioning system (global positioning system, GPS), a vehicle speed sensor, an inertial measurement unit (inertial measurement unit, IMU), a radar unit, a laser rangefinder, an imaging device, a wheel speed sensor, a steering sensor, a gear sensor, or other elements for automatic detection, and so forth.

The control system 1801 may include several elements, such as a steering unit, a braking unit, a lighting system, an autopilot system, a map navigation system, a network timing system, and an obstacle avoidance system, as shown. Optionally, the control system 1801 may further include elements such as a throttle controller and an engine controller for controlling the running speed of the vehicle, which are not limited in this application.

The peripheral device 1803 may include several elements such as a communication system, a touch screen, a user interface, a microphone, and a speaker, among others, as shown. Wherein the communication system is used for realizing network communication between the vehicle and other devices except the vehicle. In practical applications, the communication system may employ wireless communication technology or wired communication technology to enable network communication between the vehicle and other devices. The wired communication technology may refer to communication between the vehicle and other devices through a network cable or an optical fiber, etc.

The power supply 1804 represents a system that provides power or energy to the vehicle, which may include, but is not limited to, a rechargeable lithium battery or lead acid battery, or the like. In practical applications, one or more battery packs in the power supply are used to provide electrical energy or power for vehicle start-up, and the type and materials of the power supply are not limited in this application.

Several functions of the vehicle are controlled by the computer system 1805. The computer system 1805 may include one or more processors (shown as one processor in the illustration) and memory (which may also be referred to as storage). In practical applications, the memory is also internal to the computer system 1805, or external to the computer system 1805, for example, as a cache in a vehicle, which is not limited in this application. Wherein,

the processor may include one or more general-purpose processors, e.g., a graphics processor (graphic processing unit, GPU). The processor may be configured to execute the relevant program or instructions corresponding to the program stored in the memory to perform the corresponding functions of the vehicle.

The memory may include volatile memory (RAM), for example; the memory may also include a non-volatile memory (ROM), flash memory (flash memory), or solid state disk (solid state drives, SSD); the memory may also comprise a combination of the above types of memories. The memory may be used to store a set of program code or instructions corresponding to the program code such that the processor invokes the program code or instructions stored in the memory to perform the corresponding functions of the vehicle. In this application, the memory may store a set of program codes for controlling the vehicle, and the processor may call the program codes to control the safe driving of the vehicle.

Alternatively, the memory may store information such as road maps, driving routes, sensor data, and the like, in addition to program codes or instructions. The computer system 1805 may implement the relevant functions of the vehicle in conjunction with other elements in the functional framework schematic of the vehicle, such as sensors in the sensor system, GPS, etc. For example, the computer system 1805 may control the direction of travel or speed of travel of the vehicle, etc., based on data input from the sensor system, without limitation.

The display system 1806 may include several elements, such as a windshield, a controller, and the projection device 400 described above. The controller is used for generating an image (such as an image containing vehicle states such as vehicle speed, electric quantity/oil quantity and the like and an image of augmented reality AR content) according to a user instruction and sending the image content to the projection device; the projection device projects the light bearing the image content to a windshield, and the windshield is used for reflecting the light bearing the image content so as to enable a virtual image corresponding to the image content to be presented in front of a driver. It should be noted that the functions of some of the elements in the display system 1806 may be implemented by other subsystems of the vehicle, for example, the controller may be an element in the control system.

Herein, fig. 18 shows that the sensor system, the control system, the computer system and the display system include four subsystems, which are only examples and not limiting. In practical applications, the vehicle may combine several elements in the vehicle according to different functions, thereby obtaining subsystems with corresponding different functions. In practice, the vehicle may include more or fewer systems or elements, and the present application is not limited thereto.

In the description of the present specification, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes or substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A projection apparatus, comprising: the display module and the light splitting unit are positioned on the light emitting side of the display module;

the display module is used for generating a first light beam and emitting the first light beam to the light splitting unit; the first light beam comprises first polarized light carrying left-eye image information and second polarized light carrying right-eye image information and having a polarization direction perpendicular to the first polarized light;

The light splitting unit is configured to perform birefringence on the first light beam, so that the first polarized light and the second polarized light in the first light beam are emitted in different directions.

2. The projection device of claim 1, further comprising:

and the light diffusion element is positioned at the light emitting side of the light splitting unit and is used for diffusing the first polarized light and the second polarized light emitted by the light splitting unit.

3. The projection device of claim 2, wherein the light diffusing element has a diffusion angle of less than 20 °.

4. The projection device of claim 2, further comprising:

the projection unit is positioned between the display module and the light splitting unit and is used for projecting the first light beam emitted by the display module to the light splitting unit;

or, the light-splitting unit is located between the light-splitting unit and the light-diffusing element, and is used for projecting the first polarized light and the second polarized light emitted by the light-splitting unit to the light-diffusing element;

or the light diffusion element is positioned at the light emitting side of the light diffusion element and used for projecting the first polarized light and the second polarized light diffused by the light diffusion element outwards.

5. The projection device of any of claims 2-4, further comprising:

and the first reflecting element is used for reflecting the first polarized light and the second polarized light diffused by the light diffusing element.

6. The projection apparatus according to any one of claims 1 to 5, wherein the light splitting unit comprises a first right angle prism and a second right angle prism, and a largest side surface of the first right angle prism is bonded with a largest side surface of the second right angle prism; the first right angle prism and the second right angle prism each comprise a birefringent crystalline material.

7. The projection device of any one of claims 1-5, wherein the light splitting unit comprises a plurality of sets of right angle prisms, each set of right angle prisms comprising a first right angle prism and a second right angle prism, a largest side of the first right angle prism being bonded to a largest side of the second right angle prism; the first right angle prism and the second right angle prism each comprise a birefringent crystalline material.

8. The projection apparatus according to claim 6 or 7, wherein an optical axis direction of the first right angle prism is perpendicular to an optical axis direction of the second right angle prism.

9. Projection apparatus according to any of claims 6-8, characterized in that the birefringent crystal material is barium metaborate.

10. The projection device of any one of claims 1-9, wherein the display module includes a light source, a polarizing beam splitter prism, a first modulator, and a second modulator;

the light source is used for emitting a second light beam to the polarization beam splitter prism;

the polarization beam splitter prism is used for reflecting the S-state polarized light in the second light beam to the first modulator and transmitting the P-state polarized light in the second light beam to the second modulator;

the first modulator is used for generating the first polarized light according to the S-state polarized light and emitting the first polarized light to the polarization beam splitter prism;

the second modulator is configured to generate the second polarized light according to the P-state polarized light, and emit the second polarized light to the polarization beam splitter prism;

the polarization beam splitter prism is further configured to combine the first polarized light and the second polarized light into the first light beam, and transmit the first light beam to the beam splitter unit.

11. The projection device of any one of claims 1-9, wherein the display module includes a light source, a polarizer, a modulator, and a polarization converter;

The light source is used for emitting a second light beam to the polarizer;

the polarizer is used for obtaining polarized light from the second light beam and providing the polarized light to the modulator; the polarized light is P-state polarized light or S-state polarized light;

the modulator is used for alternately generating the first polarized light and the third polarized light according to the polarized light;

the polarization converter is used for transmitting the first polarized light to the light splitting unit; the third polarized light is converted into the second polarized light and emitted to the light splitting unit.

12. A display device comprising a processor and a projection apparatus according to any one of claims 1 to 11, the processor being arranged to send image data to the display module.

13. A vehicle comprising a second reflective element and the display device of claim 12 mounted on the vehicle for emitting the first polarized light and the second polarized light in different directions to the second reflective element, the second reflective element for reflecting the first polarized light and the second polarized light.

14. The vehicle of claim 13, further comprising a first film layer formed on any one of the reflective surfaces of the second reflective element, the first film layer configured to enhance reflection of polarized light of one or more polarization states by the second reflective element.

15. The vehicle of claim 14, wherein the second reflective element comprises a front windshield for reflecting the first polarized light and the second polarized light to the left and right eyes of an observer, respectively.

16. The vehicle of claim 15, wherein the front windshield comprises a first glass layer proximate to the cockpit and a second glass layer distal to the cockpit; the vehicle further includes a second film layer positioned between the first glass layer and the second glass layer, the second film layer being configured to refract light reflected by a surface of the second glass layer such that the light reflected by the surface of the second glass layer is different from a propagation direction of the light reflected by the first glass layer.