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WO2024159376A1 - 投影装置、显示设备、运载工具和投影方法 - Google Patents

投影装置、显示设备、运载工具和投影方法 Download PDF

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Publication number
WO2024159376A1
WO2024159376A1 PCT/CN2023/073891 CN2023073891W WO2024159376A1 WO 2024159376 A1 WO2024159376 A1 WO 2024159376A1 CN 2023073891 W CN2023073891 W CN 2023073891W WO 2024159376 A1 WO2024159376 A1 WO 2024159376A1
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WO
WIPO (PCT)
Prior art keywords
polarized light
light beam
reflective polarizer
state
polarization
Prior art date
Application number
PCT/CN2023/073891
Other languages
English (en)
French (fr)
Inventor
赵东峰
周鹏程
陈兴宇
张虎
童开年
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2023/073891 priority Critical patent/WO2024159376A1/zh
Priority to CN202380014760.5A priority patent/CN118765380A/zh
Publication of WO2024159376A1 publication Critical patent/WO2024159376A1/zh

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays

Definitions

  • the present application relates to projection imaging technology, which is applied to the field of intelligent automobile enhanced display technology, and in particular to a projection device, a display equipment, a vehicle and a projection method.
  • AR-HUD augmented reality head-up display
  • AR-HUD is a combination of holographic augmented reality technology (AR) and head-up display function (HUD).
  • AR holographic augmented reality technology
  • HUD head-up display function
  • AR-HUD technology is gradually being widely used in large, medium and small passenger cars, commercial vehicles and engineering vehicles, fully enabling the improvement of smart cockpit performance experience.
  • the mass production solution for AR-HUD is the free-form surface solution, that is, the picture generation unit (PGU) generates a real-focus image, and then two or three free-form surfaces form a virtual image that is magnified more than 100 times.
  • the field of view (FOV) and virtual image distance (VID) are important parameters that affect the imaging effect of AR-HUD display technology. The larger the FOV and VID, the higher the degree of integration of digital information and display scenes, and the better the driver's experience.
  • the volume of AR-HUD devices increases. For example, for an AU-HUD with a FOV of 15 ⁇ 5 degrees and a VID of 7.5 meters, the volume can be around 15 liters; for an AU-HUD with a FOV of 20 ⁇ 8 degrees and a VID of 20 meters, the volume will increase to around 25 liters.
  • the embodiments of the present application disclose a projection device, a vehicle, a display equipment and a projection method.
  • the present application provides a method for changing the polarization state of a light beam by a polarization component, which can increase the field of view angle and virtual image distance of the projection device while correspondingly reducing the volume of the projection device.
  • an embodiment of the present application discloses a projection device, including: an image generating unit, a reflective polarizer, a first curved mirror, and a first polarization converter, wherein the image generating unit is used to emit a polarized light beam; the first polarization converter is located between the reflective polarizer and the first curved mirror, and is used to transmit and change the polarization state of the polarized light beam; the first curved mirror is used to process the polarized light beam; after the polarized light beam is emitted by the image generating unit, it is transmitted to the first polarization converter via the reflective polarizer, and is transmitted to the first curved mirror via the first polarization converter, and is transmitted to the first polarization converter via the first curved mirror, and is transmitted to the reflective polarizer via the first polarization converter.
  • the image generating unit By setting the image generating unit to emit a polarized light beam, and by means of different responses to the polarization state of the light beam by the reflective polarizer, the first polarization converter, and the curved reflective mirror, when the light beam is transmitted back and forth between the reflective polarizer and the curved mirror, the polarization state of the light beam is selected.
  • the light is selectively transmitted and reflected by the reflective polarizer, and the reflective polarizer does not need to avoid the light beam transmitted back and forth, so the volume of the projection device is reduced accordingly.
  • the FOV and VID of the projection device are increased, the volume of the projection device is effectively controlled to increase slightly, remain unchanged, or decrease.
  • the reflective polarizer is used to transmit a polarized light beam whose polarization state is a first state and reflect a polarized light beam whose polarization state is a second state;
  • the polarization states include linear polarized light and circular polarized light
  • the polarized light beam in the first state includes first state linear polarized light and first state circular polarized light
  • the polarized light beam in the second state includes second state linear polarized light and second state circular polarized light.
  • the first curved mirror includes a first curved reflector
  • the image generating unit is located on a side of the reflective polarizer close to the first curved reflector, the image generating unit emits a polarized light beam, and the polarization state of the polarized light beam is a second-state linear polarized light
  • the polarized light beam is reflected by the reflective polarizer and propagates to the first polarization converter
  • the polarized light beam passes through the first polarization converter
  • its polarization state is converted into a second-state circularly polarized light, and is propagated to the first curved reflector through the first polarization converter
  • the polarized light beam is reflected by the first curved reflector
  • the polarization state of the polarized light beam is converted into a first-state circularly polarized light, and is propagated to the first polarization converter, the polarized light beam passes through the first polarization converter, and its polarization
  • the light beam can be first reflected by the reflective polarizer, and the reflected light beam can be converted into a polarization state through the curved mirror and the first polarization converter, and then pass through the reflective polarizer, so that the reflective polarizer and the image generating unit can be arranged longitudinally in the center console, thereby reducing the lateral size of the projection device.
  • the first polarization converter includes a quarter wave plate.
  • the first curved mirror includes a first curved reflector
  • the image generating unit is located on a side of the reflective polarizer close to the first curved reflector, the image generating unit emits a polarized light beam, and the polarization state of the polarized light beam is a second state linear polarized light
  • the polarized light beam passes through the first polarization converter, and its polarization state is converted to a second state circular polarized light, and is reflected by the reflective polarizer, and its polarization state is converted to a first state circular polarized light, and propagates to the first polarization converter
  • the polarized light beam passes through the first polarization converter, and its polarization state is converted to a first state linear polarized light and propagates to the first curved reflector
  • the polarized light beam is reflected by the first curved reflector
  • the polarized light beam reflected by the first curved reflector propagates to the first polarized light
  • the reflective polarizer can reflect the second state circular polarized light and pass through the first state circular polarized light, and the projection device can choose to pass more states of polarized light.
  • the first curved mirror includes a free-form surface reflective mirror
  • the image generating unit is located on a side of the free-form surface reflective mirror away from the reflective polarizer, the image generating unit emits a polarized light beam
  • the polarization state of the polarized light beam is a second-state linear polarized light
  • the polarized light beam passes through the free-form surface reflective mirror
  • the polarized light beam passing through the free-form surface reflective mirror passes through the first polarization converter, its polarization state is converted into a second-state circularly polarized light, and is reflected by the reflective polarizer, its polarization state is converted into a first-state circularly polarized light, and is propagated to the first polarization converter
  • the polarized light beam passes through the first polarization converter, its polarization state is converted into a first-state linear polarized light and is propagated to the free-form surface reflective mirror, the polarized light beam
  • a polarization converter whose polarization state is converted into a first state circularly polarized light, and propagates to the reflective polarizer through the first polarization converter, and passes through the reflective polarizer.
  • the curved mirror is composed of a free-form surface transflective mirror, and the curved mirror also has the selective transmittance of the polarized state light beam. When setting, the curved mirror can avoid the incident light beam, further reducing the volume of the projection device.
  • the first curved mirror includes a first curved reflector, the image generating unit is located on a side of the reflective polarizer away from the first curved reflector, the image generating unit emits a polarized light beam, and the polarization state of the polarized light beam is a second state linear polarized light; the polarized light beam passes through the reflective polarizer, and the polarized light beam passing through the reflective polarizer is propagated to the first polarization converter, the polarized light beam passes through the first polarization converter, and its polarization state is converted into a second state circularly polarized light, and is propagated to the first curved reflector through the first polarization converter, the polarized light beam is reflected by the first curved reflector, and the polarization state of the polarized light beam is converted into a first state circularly polarized light, and is propagated to the first polarization converter, the polarized light beam passes through the first
  • the reflective polarizer first transmits the light beam, and the transmitted light beam changes its polarization state through the curved mirror and the first polarization converter, and then reflects out of the projection device through the reflective polarizer.
  • the reflective polarizer does not need to avoid the returned light beam, effectively reducing the size of the projection device.
  • the projection device further includes a second polarization converter
  • the projection device further includes a second polarization converter
  • the second polarization converter is located on a side of the reflective polarizer away from the first curved reflector, and the second polarization converter is used to convert the polarized light beam emitted through the reflective polarizer from circular polarized light to linear polarized light, so that the projection device emits linear polarized light outwardly, and the linear polarized light is consistent with the polarization type of the incident light beam emitted by the image generating unit in the projection device.
  • the second polarization converter includes a quarter wave plate or a half wave plate.
  • the first polarization converter includes a quarter wave plate or a half wave plate.
  • the reflective polarizer includes a polarizing element, and the polarizing element includes at least one of a liquid crystal polarizer or a reflective polarizer.
  • the liquid crystal polarizer can be controlled by a voltage of a liquid crystal material, and selective transmission of different circularly polarized light states can be achieved by rotating the liquid crystal.
  • the reflective polarizer also includes a base layer, and the polarizing element is bonded to the base layer to support the reflective polarizer in the projection device to prevent the reflective polarizer from vibrating and causing image shaking.
  • the projection device further includes a lens element, the lens element is located at the light beam exit end of the projection device, and the lens element is used to adjust the optical path of the exiting light beam.
  • the lens element can optically adjust the light beam emitted by the projection device, improve the optical quality of the entire architecture of the projection device, and reduce the difficulty of designing and processing free-form surfaces in the curved mirror.
  • each module is prepared in a standardized manner. When facing different optical requirements such as different vehicle models, the processing parameters of the lens element can be designed to meet multiple performances of the projection device, thereby reducing the overall development difficulty and cost of the projection device.
  • the optical design in the projection device is determined or optimized based on performance indicators, material selection, testability and acceptance, tolerance control, processing and assembly, and cost. These considerations should be carried out throughout the process from the beginning of product design to the end of product generation, as well as the equipment debugging process in product applications. Throughout the entire process, especially for head-up display devices, the design parameters of the free-form surface mirror have a great influence on the imaging quality of the entire product, and the parameter design and product preparation of the free-form surface mirror have high requirements on the process.
  • the present application proposes that when the free-form surface achieves the same indicators, adding lens elements is equivalent to increasing the optimization dimension of the optical design.
  • the imaging of the projection device can be optimized by adjusting the parameter design of the lens elements, and the requirements for the free-form surface indicators are reduced. At the same time, changing the lens element can meet certain performance index requirements of the projection device, and thus there is no need to change the free-form surface, reducing the difficulty and complexity of optical system optimization.
  • the projection device further includes a light homogenizing element, the light homogenizing element is located on the light exiting side of the image generating unit, and the light homogenizing element is used to realize the projection image plane of the image generating unit.
  • the light homogenizing element can receive the real image of the image generating unit, and perform light homogenization and optical expansion angle control on the image, so as to provide a display object plane for the polarization folding component in the projection device.
  • the projection device further includes an anti-glare film, and the anti-glare film is used to process the polarized light beam to reduce or prevent glare.
  • the anti-glare film can change the symmetry center of light reflection.
  • an embodiment of the present application provides a display device, comprising an imaging screen and any one of the projection devices described above, wherein the imaging screen is used to receive light emitted by the projection device and form an image.
  • the display device includes holographic glasses and/or a helmet.
  • an embodiment of the present application discloses a vehicle, comprising a windshield and any one of the projection devices or display equipment described above, wherein the vehicle comprises a projection medium, and the projection medium is used to receive the light emitted by the projection device and form an image.
  • an embodiment of the present application discloses a projection method, which is applied to a projection device, wherein the projection device includes an image generating unit, a reflective polarizer, a first curved mirror, and a first polarization converter; the method includes:
  • the image generating unit emits a polarized light beam, which is transmitted to the first polarization converter via the reflective polarizer, and then transmitted to the first curved mirror via the first polarization converter, then transmitted to the first polarization converter via the first curved mirror, then transmitted to the reflective polarizer via the first polarization converter, and finally projected out of the projection device via the reflective polarizer.
  • FIG1 is a schematic diagram of a field of view
  • Fig. 2 is a schematic diagram of virtual image distance
  • FIG3 is a schematic diagram of an application scenario of a projection device provided by an embodiment of the present application in the automotive field;
  • FIG4 is a schematic diagram of another perspective of an application scenario of a projection device in the automotive field provided by an embodiment of the present application;
  • FIG5 is a schematic diagram of an imaging device provided by an embodiment of the present application, which projects an image into the eyes of a driver in the automotive field;
  • FIG6 is a schematic diagram of a light path of a projection device provided by an embodiment of the present application for use in the automotive field;
  • FIG7 is a schematic diagram of light beam transmission of a projection device provided by an embodiment of the present application in the field of head-up display;
  • FIG8 is a schematic diagram of a change in polarization state of a light beam of a projection device provided in an embodiment of the present application.
  • FIG9 is another schematic diagram of light beam transmission of a projection device provided by an embodiment of the present application in the field of head-up display;
  • FIG10 is a schematic diagram showing another change in the polarization state of a light beam of a projection device provided in an embodiment of the present application.
  • FIG11 is another schematic diagram of light beam transmission of a projection device provided by an embodiment of the present application in the field of head-up display;
  • FIG12 is a schematic diagram showing another change in the polarization state of a light beam of a projection device provided in an embodiment of the present application.
  • FIG13 is another schematic diagram of light beam transmission of a projection device provided by an embodiment of the present application in the field of head-up display;
  • FIG14 is a schematic diagram showing another change in the polarization state of a light beam of a projection device provided in an embodiment of the present application.
  • FIG15 is a schematic diagram of a lens element disposed in a projection device provided in an embodiment of the present application.
  • FIG16 is a schematic diagram of a light homogenizing element provided in a projection device according to an embodiment of the present application.
  • FIG17 is a schematic diagram of an anti-glare film provided in a projection device according to an embodiment of the present application.
  • FIG18 is a schematic diagram of a processor provided in a projection device according to an embodiment of the present application.
  • FIG19 is a schematic diagram of two curved mirrors in a projection device provided in an embodiment of the present application.
  • FIG20 is a structural schematic diagram of a computing device provided in an embodiment of the present application.
  • At least one refers to one or more, and “plurality” refers to two or more.
  • At least one of the following” or similar expressions refers to any combination of these items, including any combination of single items or plural items.
  • at least one of a, b, or c can be represented by: a, b, c, (a and b), (a and c), (b and c), or (a and b and c), where a, b, c can be single or multiple.
  • “And/or” describes the association relationship of associated objects, indicating that three relationships can exist.
  • a and/or B can be represented by: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.
  • the character "/" generally indicates that the associated objects before and after are in an "or” relationship.
  • first and second used in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects.
  • first spectrometer and the second spectrometer are only used to distinguish different spectrometers, and do not indicate the differences in the structures, detection principles, importance, etc. of the two devices.
  • references to "one embodiment” or “an embodiment” in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrases “in one embodiment” or “in an embodiment” appearing in various places in this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the particular features, structures, or characteristics can be combined in any appropriate manner, as would be apparent to one of ordinary skill in the art from this disclosure.
  • Field of view also known as field of view, refers to the maximum stereo angle from the edge of the displayed image to the image acquisition center.
  • FOV Field of view
  • the center of the lens of the optical measuring device is the image acquisition center, and the target image measured by the optical measuring device can pass through the lens, and the angle formed by the two edges with the largest range through the lens is the field of view.
  • the angle between the two side edges of the image projected by the projection device on the imaging mechanism and the center point of the projection device lens is the field of view, usually the two edge points with the largest distance.
  • the image acquisition center is the pupil of the human body.
  • FOV In the field of projection, FOV generally includes vertical field of view angle, horizontal field of view angle and diagonal field of view angle.
  • point O in Figure 1 is the image acquisition center
  • the quadrilateral enclosed by ABCD is the projection imaging
  • the angle between the OA line and the OB line can be the horizontal field of view angle
  • the angle between the OB line and the OC line can be the vertical field of view angle
  • the angle between the OA line and the OC line can be the diagonal field of view angle.
  • the default field of view angles are generally the horizontal field of view angle and the vertical field of view angle.
  • Virtual Image Distance also known as virtual image distance, refers to the distance from the projected virtual image to the image acquisition center.
  • the image acquisition center is the human pupil.
  • the virtual image distance is the straight-line distance between the human pupil and the virtual image.
  • FIG3 shows a schematic diagram of an application scenario of a projection device 100 provided in an embodiment of the present application in the automotive field.
  • FIG4 shows a schematic diagram of another perspective of an application scenario of a projection device 100 provided in an embodiment of the present application in the automotive field.
  • FIG5 shows an imaging schematic diagram of a projection device 100 provided in an embodiment of the present application in the automotive field projecting an image into the driver's eyes, which shows that the projection device 100 in FIG3 and FIG4 projects an image into the driver's eyes, so that the driver can see virtual image information.
  • the driver looks outside the car through the windshield 200, he can see a virtual image with a certain depth of field (i.e., the distance of a clear image presented within the range before and after the image focus).
  • the information in front of the car is obtained through information acquisition modules such as cameras and infrared sensors.
  • the road information in front includes the distance between the front vehicles, the speed of the front vehicles and the road information, and the corresponding digital information is projected in an imaging manner to be closely combined with the environmental information of the front vehicle, wherein the digital information includes: vehicle speed, navigation information (road instructions), vehicle gear, cruise control, distance between the front vehicles, the speed of the front vehicles, speed information, power information, cruising range information, audio and video entertainment system information, etc., so that the driver can understand the information required for driving the vehicle 1 without shifting his sight when driving the vehicle 1.
  • the car needs to have a head-up display system (Head Up Display, HUD), wherein the enhanced head-up display system may include a projection device 100 and an optical element, the projection device 100 can project an image, and the optical element may include the windshield 200 of the vehicle, or a reflective film attached to the windshield 200, or a separate screen set in the car cabin.
  • the optical element can reflect and/or refract the image projected by the projection device 100 and then project it into the driver's eyes, so that the driver can obtain a virtual information image in front of the windshield 200 .
  • the field of view can be 15 ⁇ 5 degrees.
  • 15 degrees refers to the horizontal field of view of 15 degrees, as shown in Figure 1, which can be the angle between the OA line and the OB line; 5 degrees refers to the vertical field of view, which can be the angle between the OB line and the OC line.
  • the size of a person's retina is limited.
  • the FOV of people's eyes is generally between 90 degrees and 120 degrees (it can be a horizontal field of view or a vertical field of view), and through binocular parallax, the human eye can perceive the 3D state of objects.
  • the increase in the corresponding FOV of the projection device can improve the fit between the virtual image and the real image, increase the coverage area of the virtual image, and the driver's visual effect is also improved accordingly.
  • the VID can be 7.5 meters. As shown in FIG2 , the VID can be the distance between the front image of the vehicle and the driver's eyes.
  • the increase in the VID of the projection device can increase the depth of the virtual image relative to the driver's field of vision, so that the virtual image and the real image in the distance fit better, and the three-dimensional effect of the virtual image is more realistic.
  • the increase in VID means that the driver does not need to frequently zoom when viewing the displayed image information and the virtual image information, which improves the driver's vision. It improves the driver's eye comfort and correspondingly increases driving safety.
  • FIG6 shows a schematic diagram of an optical path of a projection device 100 used in the automotive field.
  • the image generating unit 110 emits a light beam to the reflector 190.
  • the cross-sectional area of the light beam emitted by the image generating unit 110 gradually increases, and is reflected and magnified by the reflector 190 to the first curved mirror 130.
  • the first curved mirror 130 reflects the light beam to the windshield 200, and the light beam is reflected to the driver's eyes through the windshield 200.
  • the first curved mirror 130 selects parameters according to factors such as the internal structure of the projection device 100, the installation position, and the shape of the display area of the windshield, so as to correct and compensate for the optical distortion caused by the different curvatures and optical path lengths of different projection areas of the windshield.
  • the optical path transmission distance in the projection device 100 needs to be increased to increase the magnification factor, and the size of the light beam reflected by the reflector 190 and the first curved mirror 130 increases, and the size of the reflector 190 and the first curved mirror 130 increases accordingly.
  • the VID of the projection device 100 is increased under the premise of ensuring image quality, the optical path transmission distance in the projection device 100 needs to be increased. Whether increasing the FOV or increasing the VID, the volume of the projection device 100 will increase.
  • the volume is mostly about 15 liters; for a projection device 100 with a FOV of 20 ⁇ 8 degrees and a VID of 20 meters, the volume can reach 25 liters, which is nearly doubled.
  • the projection device 100 for realizing the enhanced head-up display function is mostly set in the center console of the car.
  • the projection device 100 can be set in the center console and located in front of the steering wheel (matching the front of the driving direction of the car).
  • the overall size of the center console is limited. It is not suitable to build a larger projection device 100.
  • the size limitation makes it impossible to achieve a larger range of FOV and VID in the current head-up display field, affecting the imaging quality.
  • the vehicle may be a traditional fuel vehicle, or a pure electric vehicle, a hybrid vehicle, or other new energy vehicle.
  • the vehicle may be any of different types of vehicles such as a sedan, a truck, a passenger bus, a sport utility vehicle (SUV), or a land transportation device such as a tricycle, a motorcycle, or a train that carries people or goods.
  • SUV sport utility vehicle
  • the projection device of the present application may also be applied to other types of vehicles such as airplanes and ships.
  • the projection device 100 includes an image generating unit 110, a reflective polarizer 120, a first curved mirror 130 and a first polarization converter 140.
  • the first curved mirror 130 can be a spherical mirror, an aspherical mirror, or a free-form mirror.
  • the first curved mirror 130 has a reflection function, which can reflect all polarized light beams and also reflect part of the polarized light beams.
  • the first curved mirror 130 takes a free-form mirror as an example.
  • the image generating unit 110 emits a light beam to the reflective polarizer 120, and the light beam is a polarized light beam, wherein the polarized light beam includes multiple states, such as linear polarized light and circular polarized light.
  • Linearly polarized light refers to a light vector that vibrates only in a fixed direction. In the direction of light propagation, the vibration of the light vector is in a plane.
  • linearly polarized light has different polarization forms, such as first-state linear polarized light and second-state linear polarized light.
  • the vibration directions of the first-state linear polarized light and the second-state linear polarized light are different.
  • the first-state linear polarized light can be P linear polarized light
  • the second-state linear polarized light can be S linear polarized light.
  • the vibration direction of the P linear polarized light is perpendicular to the vibration direction of the S linear polarized light.
  • first and second do not constitute a limitation on the form of linear polarized light.
  • the first-state linear polarized light can also be S linear polarized light, and the second-state linear polarized light can also be P linear polarized light.
  • Circularly polarized light refers to light whose electric vector traces a circular trajectory along the direction of light beam transmission.
  • Circularly polarized light has different polarization forms, such as first-state circularly polarized light and second-state circularly polarized light.
  • the first-state circularly polarized light and the second-state circularly polarized light have different rotation directions.
  • the first-state circularly polarized light can be right-handed circularly polarized light
  • the second-state circularly polarized light can be right-handed circularly polarized light.
  • first and second do not constitute a limitation on the form of circularly polarized light, and the first state circularly polarized light can also be left-handed circularly polarized light, and the second state circularly polarized light can also be right-handed circularly polarized light.
  • the light beam emitted by the image generating unit 110 is transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130.
  • the first polarization converter 140 is located between the reflective polarizer 120 and the first curved mirror 130.
  • the light beam transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130 can pass through the first polarization converter 140.
  • the first polarization converter 140 can transform the polarization state of the transmitted light beam, for example, transform linear polarized light into circular polarized light, or transform circular polarized light into linear polarized light.
  • the image generating unit 110 is a real image generating unit, also called a picture generation unit (PGU), which mainly includes a micro display (LCoS, DLP, LBS and MicroLED, etc.), an illumination light source and system (the illumination light source can be LED or Laser, or a combination of the two) and an imaging lens unit, etc.
  • PGU picture generation unit
  • the reflective polarizer 120 is a polarization device with polarization state selective transmittance.
  • the reflective polarizer 120 can transmit polarized light in the first state and reflect polarized light in the second state.
  • the polarization direction of the reflective polarizer 120 is consistent with the vibration direction of the P linear polarized light.
  • the reflective polarizer 120 reflects the S linear polarized light, and the reflected S linear polarized light is converted into circular polarized light through the first polarization converter 140.
  • the first curved mirror 130 can reflect the circular polarized light and change the rotation direction of the circular polarized light.
  • the light beam passes through the first polarization converter 140 again, it can be converted into P linear polarized light.
  • the P linear polarized light can pass through the reflective polarizer 120 and pass through the reflective polarizer 120 to be transmitted to the outside of the projection device 100.
  • the polarization direction of the reflective polarizer 120 is consistent with the vibration direction of the S-linear polarized light.
  • the reflective polarizer 120 transmits the S-linear polarized light, and the transmitted S-linear polarized light is converted into circularly polarized light through the first polarization converter 140.
  • the first curved mirror 130 can reflect the circularly polarized light and change the rotation direction of the circularly polarized light.
  • the light beam passes through the first polarization converter 140 again, it can be converted into P-linear polarized light.
  • the P-linear polarized light is reflected by the reflective polarizer 120 and is reflected and transmitted to the outside of the projection device 100.
  • This embodiment only describes the two ways in which the present application selects the transmittance according to the polarization state of the reflective polarizer 120 to achieve the increase of FOV and VID, and controls the overall volume increase of the projection device 100.
  • the present application is not limited to being implemented in the above two ways. The remaining implementation methods are described below.
  • the reflective polarizer 120 described in the present application includes a polarizing element, which may be a reflective polarizer, which has polarization state selective transmittance, and the first polarization converter 140 changes the polarization state of the light emitted by the image generating unit 110; when the light beam incident on the first curved mirror 130 is circularly polarized light, the first curved mirror 130 may also change the polarization form of the circularly polarized light.
  • a polarizing element which may be a reflective polarizer, which has polarization state selective transmittance
  • the first polarization converter 140 changes the polarization state of the light emitted by the image generating unit 110; when the light beam incident on the first curved mirror 130 is circularly polarized light, the first curved mirror 130 may also change the polarization form of the circularly polarized light.
  • the polarization state and form between the reflective polarizer 120 and the first curved mirror 130 are transformed, so that when the light beam is transmitted to the reflective polarizer 120 in different polarization states, the first state polarized light can pass through the reflective polarizer 120, and the second state polarized light is reflected by the reflective polarizer 120; when designing the optical path of the projection device 100, the reflective polarizer 120 does not need to avoid the light beam transmitted back and forth, and the light beam transmitted back and forth refers to the light beam between the reflective polarizer 120 and the first curved mirror 130.
  • the areas of the reflective polarizer 120 and the first curved mirror 130 are increased accordingly, and the light beam transmission distance (the spacing between the image generating unit 110, the reflective polarizer 120 and the first curved mirror 130 is increased) is also increased accordingly; the reflective polarizer 120 does not need to avoid the light beam transmitted back and forth, so as to balance the increase in the volume of the projection device 100 caused by the increase in the area of the reflective polarizer 120 and the first curved mirror 130, and the increase in the volume of the projection device 100 caused by the increase in the light beam transmission distance, thereby achieving a small increase in the volume of the projection device 100, no change in volume, or a reduction in volume.
  • FIG. 7 shows a schematic diagram of light beam transmission of the projection device 100 in the head-up display field in this implementation
  • FIG. 8 shows a schematic diagram of light beam polarization of the projection device 100 in this implementation. Schematic diagram of state changes.
  • the image generating unit 110 is located below the reflective polarizer 120, wherein the downward direction refers to the direction corresponding to the normal driving state of the automobile.
  • the projection device 100 is located in the center console as a whole, and the center console is located below the windshield 200.
  • the downward direction in FIG7 is the Y direction, which corresponds to the downward direction of the automobile in the driving state; the right direction in FIG7 is the X direction, which corresponds to the rear of the automobile in the driving state.
  • the image generating unit 110 is located in the Y direction of the reflective polarizer 120 and is offset in the X direction.
  • the image generating unit 110 emits an incident light beam 111 toward the reflective polarizer 120.
  • the incident light beam 111 is a light beam emitted by the image generating unit 110 and contacts the reflective polarizer 120 for the first time.
  • the incident light beam 111 is a second state linear polarized light.
  • the second state linear polarized light takes S linear polarized light as an example, and the double-headed arrow tilted in the upper right and lower left direction in FIG8 represents S linear polarized light.
  • a first returned light beam 112 is formed.
  • the first returned light beam 112 is S linear polarized light, which is converted into second state circular polarized light after passing through the first polarization converter 140.
  • the second state circular polarized light takes left-handed circular polarized light as an example, and the arc-shaped arrow in the counterclockwise direction in FIG8 represents left-handed circular polarized light.
  • a second returned light beam 113 is formed.
  • the light beam processed by the optical element can partially pass through the reflective polarizer 120 again, and partially no longer pass through the reflective polarizer 120.
  • the processed light beam can also pass through the reflective polarizer 120 again. This application does not limit the amount of the light beam passing through the reflective polarizer after processing.
  • the first curved mirror 130 includes a first curved reflector 131.
  • This embodiment takes a free-form reflector as an example to correct the aberration caused by the irregular curved surface of the windshield.
  • the surface shape of the optical element used in traditional optical design is a standard spherical surface, which generally requires multiple spherical mirrors to cooperate to correct the aberration, resulting in a relatively complex optical structure and a large space occupation. With the development of the optical industry, the design and manufacturing technology of aspheric surfaces with relatively complex surface shapes has been greatly improved.
  • Aspheric surfaces generally refer to secondary curved surfaces such as paraboloids, ellipsoids, involutes, hyperboloids, and higher-order curved surfaces with a rotation axis, as well as non-rotating aspheric surfaces, such as off-axis aspheric surfaces.
  • one aspheric surface can usually replace two or more spherical surfaces to correct aberrations, thereby simplifying the optical structure and realizing the miniaturization and lightweighting of the optical path.
  • free-form surfaces are more complex optical structures.
  • the radius of curvature at each point on the surface is different, and the degree of freedom of the surface shape is very high.
  • Free-form surfaces can not only replace multiple aspheric surfaces to correct aberrations, but also maximize optical quality and simplify optical structures.
  • Optical free-form surfaces have complex surface structures and high degrees of freedom. There is no clear expression definition. It is generally believed that optical surfaces that do not have global rotational symmetry, have no unified optical axis, and have multiple radii of curvature on the entire surface are optical free-form surfaces.
  • the second reflected light beam 113 After being reflected by the first curved reflector 131, the second reflected light beam 113 is transformed into right-handed circularly polarized light.
  • the clockwise arc arrow in FIG8 indicates right-handed circularly polarized light.
  • the right-handed circularly polarized light is transformed into P-linearly polarized light after passing through the first polarization converter 140.
  • the double-headed arrow tilted in the upper left and lower right direction in FIG8 indicates P-linearly polarized light.
  • the second reflected light beam 113 with P-linear polarization can pass through the reflective polarizer 120 and be reflected by the windshield 200 to form an image in the driver's eyes.
  • the image generating unit 110 is arranged to emit a polarized light beam, and the reflective polarizer 120, the first polarization converter 140 and the first curved reflector 131 respond differently to the polarization state of the light beam, so that when the light beam is transmitted back and forth between the reflective polarizer 120 and the first curved reflector 131, it is selectively transmitted and reflected by the reflective polarizer 120, and the reflective polarizer 120 does not need to avoid the light beam transmitted back and forth, and the volume of the projection device 100 is reduced accordingly.
  • the FOV and VID of the projection device 100 are increased, the volume of the projection device 100 is effectively controlled to increase slightly, remain unchanged, or decrease.
  • the second state linear polarized light described in this embodiment can also be P linear polarized light.
  • a first reflected light beam 112 is formed.
  • the first reflected light beam 112 is P linear polarized light, which is converted into the second state circular polarized light after passing through the first polarization converter 140.
  • the second state circular polarized light can be The first returned light beam 112 in a right-handed circularly polarized state is reflected by the first curved reflector 131 to form a second returned light beam 113 .
  • the second reflected light beam 113 after being reflected by the first curved reflector 131 is converted into left-handed circularly polarized light, and the left-handed circularly polarized light is converted into S-linearly polarized light after passing through the first polarization converter 140.
  • the second reflected light beam 113 with S-linear polarization can pass through the reflective polarizer 120 and is imaged in the driver's eyes after being reflected by the windshield 200.
  • the reflective polarizer 120 can be a reflective polarizer with polarization characteristics, and two different refractive index materials can be used to form a multilayer film, such as a dual brightness enhancement film (DBEF), and can be a reflective polarized brightness enhancement film, which is composed of multiple layers, such as a diffusion layer, a multilayer reflective polarizer and a diffusion layer, etc. are stacked in sequence.
  • the reflective polarizer can be separately bonded to the base layer, and the base layer can be a polycarbonate (PC) or a glass substrate.
  • the size of the first polarization converter 140 and the spacing between the reflective polarizer and the first polarization converter 140 can be designed according to the optical system architecture of the projection device 100.
  • the spacing design of the reflective polarizer 120 and the first curved reflector 131 is also designed according to the optical system architecture of the projection device 100.
  • the first polarization converter 140 can be a quarter wave plate (QWP) or a half wave plate (HWP).
  • the wave plate is a parallel plane thin plate made of crystal, and the material can be a wafer cut along the optical axis parallel to the birefringent crystal such as crystal or calcite, or a mica sheet, cellophane or polyvinyl alcohol with propagation directionality for the incident light.
  • the wave plate can be bonded to the reflective surface of the first curved reflector 131, or bonded separately to a polycarbonate (PC) or glass substrate.
  • PC polycarbonate
  • FIG. 9 shows another schematic diagram of light beam transmission of the projection device 100 in the head-up display field in the implementation
  • FIG. 10 shows another schematic diagram of changes in the light beam polarization state of the projection device 100 in the implementation.
  • the image generating unit 110 is located below the reflective polarizer 120, wherein the downward direction refers to the direction corresponding to the normal driving state of the automobile, and the projection device 100 is located in the center console as a whole, and the center console is located below the windshield.
  • the downward direction in FIG9 is the Y direction, which corresponds to the downward direction of the automobile in the driving state; the right direction in FIG9 is the X direction, which corresponds to the rear direction of the automobile in the driving state.
  • the image generating unit 110 is located in the Y direction of the reflective polarizer 120 and is offset in the X direction.
  • the image generating unit 110 emits an incident light beam 111 toward the reflective polarizer 120.
  • the incident light beam 111 is a light beam emitted by the image generating unit 110 and contacts the reflective polarizer 120 for the first time.
  • the second state polarized light takes left-handed circularly polarized light as an example
  • the image generating unit 110 emits an incident light beam 111 in an S linear polarization state
  • the double-headed arrow inclined in the upper right and lower left direction in FIG. 10 represents S linear polarized light.
  • the incident light beam 111 in S linear polarization first passes through the first polarization converter 140 and is converted into left-handed circularly polarized light, and the counterclockwise arc arrow in FIG.
  • the left-handed circularly polarized light is the second state polarized light described in the present embodiment, and the left-handed circularly polarized light is converted into right-handed circularly polarized light after being reflected by the reflective polarizer 120, and the clockwise arc arrow in FIG. 10 represents right-handed circularly polarized light, forming a first reflected light beam 112.
  • the first reflected light beam 112 is right-handed circularly polarized light, and after passing through the first polarization converter 140, it is converted into a first-state linearly polarized light.
  • the first-state circularly polarized light takes P linearly polarized light as an example.
  • the double-headed arrows inclined in the upper left and lower right directions in Figure 10 represent P linearly polarized light.
  • the first reflected light beam 112 in the P linear polarization state is reflected by the first curved reflector 131 to form a second reflected light beam 113.
  • the first curved mirror 130 includes a first curved reflector 131.
  • This embodiment takes a free-form reflector as an example to correct the aberration caused by the irregular curved surface of the windshield.
  • the second reflected light beam 113 after being reflected by the first curved reflector 131 is in a P linear polarization state.
  • the second reflected light beam 113 in the P linear polarization state is converted into a first state polarized light through the first polarization converter 140.
  • the right-handed circularly polarized light is the first state polarized light described in this embodiment.
  • the right-handed circularly polarized light can pass through the reflective polarizer 120 and is reflected by the windshield 200. The image is then formed in the driver's eyes.
  • the second state polarized light described in this embodiment can also take right-handed circularly polarized light as an example.
  • the image generating unit 110 emits an incident light beam 111 in a P linear polarization state.
  • the P linear polarized light is converted into a second state polarized light after passing through the first polarization converter 140.
  • the second state polarized light can be right-handed circularly polarized light.
  • After the right-handed circularly polarized light is reflected by the reflective polarizer 120, it forms a first reflected light beam 112.
  • the first reflected light beam 112 is left-handed circularly polarized light.
  • After passing through the first polarization converter 140 it is converted into a first state linear polarized light.
  • the first state linear polarized light can be a P linear polarized light.
  • the first reflected light beam 112 in a P linear polarization state is reflected by the first curved reflector 131 to form a second reflected light beam 113.
  • the second reflected light beam 113 after being reflected by the first curved reflector 131 is in a P-linear polarization state.
  • the P-linear polarized light is converted into right-handed circularly polarized light after passing through the first polarization converter 140.
  • the second reflected light beam 113 in a right-handed circularly polarized state can pass through the reflective polarizer 120 and be reflected by the windshield 200 to form an image in the driver's eyes.
  • the reflective polarizer 120 includes a polarizing element, which may be a liquid crystal polarizer with polarization characteristics.
  • the liquid crystal polarizer may realize liquid crystal deflection by controlling voltage, thereby realizing reflection of left-handed circularly polarized light and transmission of right-handed circularly polarized light, or realizing reflection of right-handed circularly polarized light and transmission of left-handed circularly polarized light.
  • the liquid crystal polarizer may be bonded to a substrate layer, which may be a polycarbonate (PC) or a glass substrate.
  • the size of the first polarization converter 140 and the spacing between the liquid crystal polarizer and the first polarization converter 140 may be designed with corresponding parameters according to the optical system architecture of the projection device 100 to ensure that the light beam passes through completely at different apertures, and to ensure that the entire size of the first polarization converter 140 is effectively utilized. Furthermore, the spacing design between the reflective polarizer 120 and the first curved reflector 131 is also designed according to the optical system architecture of the projection device 100.
  • the first polarization converter 140 can be a quarter wave plate (QWP) or a half wave plate (HWP).
  • the wave plate is a parallel plane thin plate made of crystal, and the material can be a wafer cut along the optical axis parallel to the birefringent crystal such as crystal or calcite, or a mica sheet, cellophane or polyvinyl alcohol with propagation directionality for the incident light.
  • the wave plate can be bonded to the reflective surface of the first curved reflector 131, or bonded separately to a polycarbonate (PC) or glass substrate.
  • PC polycarbonate
  • the wave plate of the first polarization converter 140 can be an integral body, such as an integral wave plate as shown in FIG9 , which simultaneously transmits the incident light beam 111, the first reflected light beam 112, and the second reflected light beam 113.
  • the wave plate of the first polarization converter 140 can be two parts, which are respectively arranged between the reflective polarizer 120 and the image generating unit 110 to transmit the incident light beam 111, and are arranged between the reflective polarizer 120 and the first curved reflector 131 to transmit the first reflected light beam 112 and the second reflected light beam 113.
  • the projection device 100 may further include a second polarization converter 150, which is disposed on a side of the reflective polarizer 120 away from the first curved reflector 131, and the circularly polarized light transmitted through the reflective polarizer 120 may pass through the second polarization converter 150, and the second polarization converter 150 converts the circularly polarized light into linearly polarized light, which may be reflected through the windshield 200 and imaged in the driver's eyes.
  • a second polarization converter 150 which is disposed on a side of the reflective polarizer 120 away from the first curved reflector 131, and the circularly polarized light transmitted through the reflective polarizer 120 may pass through the second polarization converter 150, and the second polarization converter 150 converts the circularly polarized light into linearly polarized light, which may be reflected through the windshield 200 and imaged in the driver's eyes.
  • FIG. 11 shows another schematic diagram of light beam transmission of the projection device 100 in the head-up display field in this implementation
  • FIG. 12 shows another schematic diagram of changes in the light beam polarization state of the projection device 100 in this implementation.
  • the incident light beam 111 in this embodiment may first pass through the reflective polarizer 120 , and the incident light beam 111 passing through the reflective polarizer 120 is transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130 , and may be reflected out of the projection device 100 by the reflective polarizer 120 .
  • the image generating unit 110 can be located to the right of the reflective polarizer 120, wherein the right refers to the rear direction of the driving direction corresponding to the normal driving state of the car.
  • the projection device 100 is located in the center console as a whole, and the center console is located below the windshield.
  • the downward direction in FIG. 11 is the Y direction, corresponding to the downward direction of the car in the driving state.
  • the right side in FIG11 is the X direction, which corresponds to the rear relative to the driving direction when the car is in a driving state.
  • the image generating unit 110 is located in the X direction of the reflective polarizer 120 and is offset in the Y direction.
  • the image generating unit 110 emits an incident light beam 111 toward the reflective polarizer 120.
  • the incident light beam 111 is a light beam emitted by the image generating unit 110 and contacts the reflective polarizer 120 for the first time.
  • the first state linear polarized light takes S linear polarized light as an example, and the double-headed arrow tilted in the upper right and lower left direction in FIG. 12 represents S linear polarized light.
  • the image generating unit 110 emits S linear polarized light, and the incident light beam 111 in the S linear polarized state is transmitted through the reflective polarizer 120 to form a transmitted light beam 114.
  • the transmitted light beam 114 is S linear polarized light, and after passing through the first polarization converter 140, it is converted into the first state circular polarized light.
  • the first state circular polarized light takes left-handed circular polarized light as an example, and the arc-shaped arrow in the counterclockwise direction in FIG. 12 represents left-handed circular polarized light.
  • the transmitted light beam 114 in the left-handed circular polarized state is reflected by the first curved reflector 131 to form a first reflected light beam 112.
  • the first curved mirror 130 includes a first curved reflector 131.
  • This embodiment takes a free-form reflector as an example to correct the aberration caused by the irregular curved surface of the windshield.
  • the first returned light beam 112 After being reflected by the first curved reflector 131, the first returned light beam 112 is transformed into right-handed circularly polarized light.
  • the clockwise arc arrow in FIG. 12 represents right-handed circularly polarized light.
  • the right-handed circularly polarized light passes through the first polarization converter 140, it is transformed into P linearly polarized light.
  • the double-headed arrow tilted in the upper left and lower right direction in FIG. 12 represents P linearly polarized light.
  • the first returned light beam 112 in the P linearly polarized state is reflected by the polarizer 120.
  • the second linearly polarized light in this embodiment can be P linearly polarized light, and forms a second returned light beam 113.
  • the reflective polarizer 120 is tilted, specifically tilted in the lower left and upper right direction, so that the second returned light beam 113 can avoid the reflective polarizer 120 and the first polarization converter 140.
  • the second returned light beam 113 in the P linearly polarized state is emitted from the projection device 100, and after being reflected by the windshield 200, it forms an image in the driver's eyes.
  • the second state linear polarized light described in this embodiment can also be S linear polarized light
  • the first state linear polarized light can also be P linear polarized light.
  • the incident light beam 111 is in a P linear polarized state. After the incident light beam 111 is transmitted through the reflective polarizer 120, a transmitted light beam 114 is formed.
  • the transmitted light beam 114 is a P linear polarized light.
  • the first state circular polarized light can be right-handed circular polarized light.
  • the transmitted light beam 114 in a right-handed circular polarized state is reflected by the first curved reflector 131 to form a first reflected light beam 112.
  • the first returned light beam 112 reflected by the first curved reflector 131 is converted into left-handed circularly polarized light, and the left-handed circularly polarized light is converted into S-linearly polarized light after passing through the first polarization converter 140.
  • the first returned light beam 112 with S-linear polarization is reflected by the reflective polarizer 120 to form a second returned light beam 113 in an S-linear polarization state.
  • the second returned light beam 113 is emitted from the projection device 100 and is imaged in the driver's eyes after being reflected by the windshield 200.
  • the reflective polarizer 120 can be a reflective polarizer with polarization characteristics, and can be made of two different refractive index materials to form a multilayer film, such as a dual brightness enhancement film (DBEF), and can be a reflective polarized brightness enhancement film, which is composed of multiple layers, such as a diffusion layer, a multilayer reflective polarizer and a diffusion layer, etc., which are stacked in sequence.
  • the reflective polarizer can be separately bonded to the base layer, and the base layer can be a polycarbonate (PC) or a glass substrate.
  • the size of the first polarization converter 140 and the spacing between the reflective polarizer and the first polarization converter 140 can be designed according to the optical system architecture of the projection device 100.
  • the spacing design between the reflective polarizer 120 and the first curved reflector 131 is also designed according to the optical system architecture of the projection device 100.
  • the first polarization converter 140 can be a quarter wave plate (QWP) or a half wave plate (HWP).
  • the wave plate is a parallel plane thin plate made of crystal.
  • the material can be a wafer cut along the optical axis parallel to the optical axis of a birefringent crystal such as crystal or calcite, or a mica sheet, glass paper, or polyvinyl alcohol with a propagation directionality for the incident light.
  • the wave plate can be attached to the reflective surface of the first curved reflector 131, or a single Uniquely bonded to polycarbonate (PC) or glass substrates.
  • PC polycarbonate
  • FIG. 13 shows another schematic diagram of light beam transmission of the projection device 100 in the head-up display field in the present implementation
  • FIG. 14 shows another schematic diagram of changes in the light beam polarization state of the projection device 100 in the present implementation.
  • the incident light beam 111 can first pass through the first curved mirror 130 and then be reflected by the reflective polarizer 120.
  • the light beam reflected by the reflective polarizer 120 is transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130, and can be emitted from the projection device 100 through the reflective polarizer 120.
  • the image generating unit 110 may be located below the reflective polarizer 120, the first curved mirror 130 is located between the reflective polarizer 120 and the image generating unit 110, and the first polarization converter 140 is located between the reflective polarizer 120 and the first curved mirror 130.
  • the lower side refers to the direction corresponding to the normal driving state of the automobile, and the projection device 100 is located in the center console as a whole, and the center console is located below the windshield.
  • the lower side in FIG. 13 is the Y direction, which corresponds to the lower side of the automobile in the driving state; the right side in FIG. 13 is the X direction, which corresponds to the rear side of the automobile in the driving state.
  • the image generating unit 110 is located in the Y direction of the reflective polarizer 120, and the image generating unit 110 sends an incident light beam 111 toward the reflective polarizer 120, and the incident light beam 111 is a light beam sent by the image generating unit 110 and contacts the reflective polarizer 120 for the first time.
  • the incident light beam 111 emitted by the image generating unit 110 is S-polarized light.
  • the double-headed arrow tilted in the upper right and lower left direction in FIG. 14 represents S-polarized light.
  • the S-polarized light can pass through the first curved mirror 130.
  • the incident light beam 111 that passes through maintains S-polarized light and passes through the first polarization converter 140.
  • the first polarization converter 140 converts the incident light beam 111 into left-handed circularly polarized light.
  • the arc-shaped arrow in the counterclockwise direction in FIG. 14 represents left-handed circularly polarized light.
  • the second state circularly polarized light can be left-handed circularly polarized light.
  • the first curved mirror 130 includes a first curved reflective mirror 132.
  • a free-form curved reflective mirror is used as an example.
  • the curved mirror has polarization selective transmittance, and can transmit the second state linear polarized light and reflect the first state linear polarized light.
  • the first curved reflective mirror 132 presents a free-form curved surface on the reflective surface, so that after the light beam is reflected, the aberration caused by the irregular curved surface of the windshield can be corrected.
  • the first state circular polarization light may be right-handed circular polarization light
  • the second state circular polarization light may be left-handed circular polarization light.
  • the first return light beam 112 after being reflected by the reflective polarizer 120 is converted into right-handed circular polarization light.
  • the clockwise arc arrow in FIG. 14 indicates right-handed circular polarization light.
  • the right-handed circular polarization light is converted into P linear polarization light after passing through the first polarization converter 140.
  • the double-headed arrow inclined in the upper left and lower right direction in FIG. 14 indicates P linear polarization light.
  • the first return light beam 112 in the P linear polarization state is reflected by the first curved reflective mirror 132, and the reflected light beam is the second return light beam 113.
  • the second return light beam 113 passes through the first polarization converter 140 and is converted into right-handed circular polarization light.
  • the first state circular polarization light may be right-handed circular polarization light.
  • the second return light beam 113 can pass through the reflective polarizer 120 and emit out of the projection device 100, and after being reflected by the windshield 200, it forms an image in the driver's eyes.
  • the second state circularly polarized light described in this embodiment can also be left-handed circularly polarized light
  • the first state circularly polarized light can also be right-handed circularly polarized light.
  • the incident light beam 111 emitted by the image generating unit 110 can present a P linear polarization state.
  • the incident light beam 111 can pass through the first curved reflector 132, and pass through the first polarization converter 140 in a P linear polarization state and be converted into right-handed circularly polarized light.
  • the reflective polarizer 120 can pass through left-handed circularly polarized light and reflect right-handed circularly polarized light.
  • the incident light beam 111 in the right-handed circularly polarized state is reflected by the reflective polarizer 120 and forms a first reflected light beam 112.
  • the first returned light beam 112 reflected by the reflective polarizer 120 is in a left-handed circular polarization state.
  • the first returned light beam 112 in the left-handed circular polarization state is converted into S-linear polarization light after passing through the first polarization converter 140.
  • the S-linear polarization light is reflected by the first curved reflective mirror 132 to form a second returned light beam 113.
  • the second returned light beam 113 is converted into a left-handed circular polarization light after passing through the first polarization converter 140.
  • the left-handed circularly polarized light can pass through the reflective polarizer 120, exit the projection device 100, and form an image in the driver's eyes after being reflected by the windshield 200.
  • the reflective polarizer 120 can be a reflective polarizer with polarization characteristics, and can be made of two different refractive index materials to form a multilayer film, such as a dual brightness enhancement film (DBEF), and can be a reflective polarized brightness enhancement film, which is composed of multiple layers, such as a diffusion layer, a multilayer reflective polarizer and a diffusion layer, etc., which are stacked in sequence.
  • the reflective polarizer can be separately bonded to the base layer, and the base layer can be a polycarbonate (PC) or a glass substrate.
  • the size of the first polarization converter 140 and the spacing between the reflective polarizer and the first polarization converter 140 can be designed according to the optical system architecture of the projection device 100.
  • the spacing design between the reflective polarizer 120 and the first curved reflector 131 is also designed according to the optical system architecture of the projection device 100.
  • the first polarization converter 140 can be a quarter wave plate (QWP) or a half wave plate (HWP).
  • the wave plate is a parallel plane thin plate made of crystal, and the material can be a wafer cut along the optical axis parallel to the birefringent crystal such as crystal or calcite, or a mica sheet, cellophane or polyvinyl alcohol with propagation directionality for the incident light.
  • the wave plate can be bonded to the reflective surface of the first curved reflector 131, or bonded separately to a polycarbonate (PC) or glass substrate.
  • PC polycarbonate
  • the projection device 100 described in this implementation further includes a lens element 160 .
  • the lens element 160 is located at the light beam emitting end of the projection device 100 .
  • the light beam output by the projection device 100 is emitted outside the projection device through the lens element 160 .
  • the lens element 160 may be disposed on the rear end beam of the returned beam reflected or transmitted by the reflective polarizer 120. After the optical coefficient of the beam is adjusted by the reflective polarizer 120, the first curved mirror 130 and the first polarization converter 140 (which may also include the second polarization converter 150), the beam is emitted to the windshield 200 through the lens element 160.
  • the lens element 160 may be disposed between the reflective polarizer 120 and the windshield 200 , and the light beam reflected by the first curved mirror 130 may all pass through the lens element 160 .
  • the lens element 160 can optically adjust the light beam emitted by the projection device 100, improve the optical quality of the entire structure of the projection device 100, and reduce the difficulty of designing and processing the free-form surface in the first curved mirror 130.
  • each module is prepared in a standardized manner.
  • the processing parameters of the lens element can be designed to meet multiple performances of the projection device 100, thereby reducing the overall development difficulty and cost of the projection device 100.
  • the lens element 160 can be made of resin, glass or micro-nano structure etc.
  • the outer contour of the lens element 160 can be a Fresnel lens, a transparent lens, an aspherical lens or a diffraction grating lens etc.
  • lens element 160 described in this embodiment can be applied to the projection device described in any of the above embodiments.
  • the optical design in the projection device 100 is determined or optimized based on performance indicators, material selection, test acceptance, tolerance control, processing and assembly, and cost. These considerations should be carried out from the beginning of product design to the end of product generation, as well as the equipment debugging process in product application. In the whole process, especially for the head-up display device, the design parameters of the free-form surface mirror have a great influence on the imaging quality of the whole product, and the parameter design and product preparation of the free-form surface mirror have high requirements on the process.
  • the present application proposes that under the condition of the same indicators achieved by the free-form surface, adding a lens element 160 is equivalent to increasing the optimization dimension of the optical design.
  • the imaging of the projection device can be optimized, and the requirements for the free-form surface indicators are reduced; at the same time, changing the lens element 160 can meet certain performance indicator requirements of the projection device, and then there is no need to change the free-form surface, which reduces the difficulty and complexity of the optical system optimization.
  • the projection device 100 further includes a light homogenizing element 170 (diffuser), which is located at the light emitting side of the image generating unit 110 , and the light beam emitted by the image generating unit 110 to the reflective polarizer 120 passes through the light homogenizing element 170 .
  • a light homogenizing element 170 diffuseuser
  • the light homogenizing element 170 can realize the projection image plane of the image generating unit 110 and the imaging object plane of the projection device 100, and its surface is a micro-nano structure, and the base material is glass, resin or glass-based resin.
  • the light homogenizing element 170 can be an independent element of a micro-array structure (MLA) and a diffractive optical element (DOE), or a device that is easy to combine with a Fresnel element combination, and the processing method can be a nano-imprinting method, an etching method or an injection molding method.
  • the light homogenization element 170 is a real screen that can receive the real image of the image generation unit 110 and perform light homogenization and optical expansion angle control on the image, thereby providing a display surface for the polarization folding component in the projection device 100 .
  • the projection device 100 further includes an anti-glare film 180, the reflective polarizer 120, the first curved mirror 130 and the first polarization converter 140 form an optical path module, and the anti-glare film 180 is located on the light-emitting side of the optical path module; specifically, as shown in FIG17 , the anti-glare film 180 may be located above the reflective polarizer 120 and between the reflective polarizer 120 and the lens element 160.
  • the light beam emitted from the optical path module passes through the anti-glare film 180 and is emitted outside the projection device 100.
  • the anti-glare film 180 can change the symmetry center of light reflection.
  • the sunlight reflected by the anti-glare film 180 deviates from the driver's visible range, for example, deviates to above the driver's eyes, and does not enter the driver's eyes, so as to avoid causing dizziness and discomfort to the driver.
  • FIG. 18 shows a schematic diagram of the structural composition of a projection device 100 .
  • the projection device 100 includes devices such as an image generating unit 110, a reflective polarizer 120, a first curved mirror 130, and a first polarization converter 140, or further includes components such as a second polarization converter 150, a lens element 160, a light homogenizing element 170, or an anti-glare film 180.
  • the projection device 100 further includes a processor 190, which can generate a virtual image, and the projection device 100 can emit a light beam of the virtual image.
  • the acquisition device acquires environmental information
  • the radar system acquires information such as the driving environment such as the vehicle in front and the road, including lane information, the distance to the vehicle in front and the speed of the vehicle in front, and the environmental information is transmitted to the processor 190, and the processor 190 processes the environmental information.
  • the processor 190 acquires relevant digital information of the driving vehicle, such as vehicle speed, navigation, car gear, cruise control, speed, power, cruising range and audio-visual entertainment system, and combines the digital information with the acquired environmental information, and combines the corresponding digital information at the corresponding environmental information.
  • the distance to the vehicle in front is displayed on the rear side of the vehicle in front, and a virtual image of the navigation information is displayed on the road surface (for example, a prompt arrow for turning left is displayed, and the virtual arrow and the displayed lane overlap).
  • the processor 190 After combining the environmental information and the digital information, the processor 190 generates a beam of light corresponding to the virtual image, and after imaging through the image generation unit 110, the reflective polarizer 120, the first curved mirror 130 and the first polarization converter 140 and other devices, it is reflected to the driver's eyes through the windshield 200 to form an image.
  • a plurality of curved mirrors may be provided in the projection device 100 described in this implementation.
  • the projection device 100 may further include a second curved mirror 133, and may further include other curved mirrors.
  • the reflective polarizer and polarization converter described in this application may be provided between the image generation unit 110 and the first curved mirror 130.
  • the present application also provides a specific implementation of a display device, the display device includes an imaging screen and the projection device described in any of the above implementations, and the light beam emitted by the projection device is refracted and/or reflected by the imaging screen to form an image.
  • the display device may be a projection device such as a projector, the display screen may be a display curtain, and the light beam emitted by the projection device 100 is directly projected onto the display screen to form an image.
  • a projection device such as a projector
  • the display screen may be a display curtain
  • the light beam emitted by the projection device 100 is directly projected onto the display screen to form an image.
  • the display device may also be a head-mounted display device that can project a virtual image in front of a person's eyes to form a virtual
  • the virtual enhanced display image such as holographic glasses and/or helmets, can be applied to enhanced display glasses and enhanced display helmets, and can also be applied to VR glasses and VR helmets. Its working principle is similar to the head-up display principle of a car, except that the design of the optical distance and optical parameters is different.
  • the present application also provides a specific implementation of a vehicle.
  • the vehicle in the present application may include a road vehicle, a water vehicle, an air vehicle, an industrial device, an agricultural device, or an entertainment device, etc.
  • the vehicle may be a vehicle, which is a vehicle in a broad sense, and may be a vehicle (such as a commercial vehicle, a passenger car, a motorcycle, a flying vehicle, a train, etc.), an industrial vehicle (such as a forklift, a trailer, a tractor, etc.), an engineering vehicle (such as an excavator, a bulldozer, a crane, etc.), agricultural equipment (such as a lawnmower, a harvester, etc.), amusement equipment, a toy vehicle, etc.
  • the present application embodiment does not specifically limit the type of vehicle.
  • the vehicle may be a vehicle such as an airplane or a ship.
  • the vehicle also includes any of the embodiments of the projection device 100 mentioned above, or includes the display device described in the above embodiments.
  • the vehicle also includes a projection medium, which may be a windshield 200, for receiving the light emitted by the projection device 100 and forming an image.
  • the projection device 100 projects an image, which is refracted and/or reflected by the projection medium such as the windshield 200 and finally enters the driver's eyes, so that when the driver looks out of the vehicle through the front windshield, he can see a virtual image with a certain depth of field outside the vehicle.
  • An embodiment of the present application also provides a projection method, which is applied to the projection device described in any of the above embodiments, and the projection device includes: an image generating unit 110, a reflective polarizer 120, a first curved mirror 130 and a first polarization converter 140.
  • the projection device includes: an image generating unit 110, a reflective polarizer 120, a first curved mirror 130 and a first polarization converter 140.
  • Step S100 the image generating unit emits a polarized light beam; specifically, the image generating unit may emit a polarized light beam through a polarizing mechanism such as a polarizing plate.
  • Step S200 the polarized light beam is transmitted to the first polarization converter through the reflective polarizer, and is transmitted to the first curved mirror through the first polarization converter, is transmitted to the first polarization converter through the first curved mirror, is transmitted to the reflective polarizer through the first polarization converter, and is projected out of the projection device through the reflective polarizer.
  • the polarized light emitted by the image generating unit is emitted toward the reflective polarizer 120.
  • the polarization direction of the reflective polarizer 120 is different from the polarization direction of the polarized light emitted by the image generating unit.
  • the reflective polarizer 120 reflects the light beam, and the light beam is transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130.
  • the first curved mirror 130 can reflect the polarized light and change the shape of the circularly polarized light, and combined with the change of the polarization shape by the first polarization converter 140, the light beam after the back and forth transmission can be transmitted when it is transmitted to the reflective polarizer 120 again, and finally reflected through the windshield to the driver's eyes for imaging.
  • the polarized light emitted by the image generating unit is emitted toward the reflective polarizer 120, and the polarization direction of the reflective polarizer 120 is the same as the polarization direction of the polarized light emitted by the image generating unit.
  • the reflective polarizer 120 transmits the light beam, and the transmitted light beam is transmitted back and forth between the reflective polarizer 120 and the first curved mirror 130.
  • the first curved mirror 130 can reflect the polarized light and change the shape of the circularly polarized light, and combined with the change of the polarization shape by the first polarization converter 140, the light beam after the back and forth transmission can be reflected when it is transmitted to the reflective polarizer 120 again, and finally reflected through the windshield to the driver's eyes for imaging.
  • FIG20 is a structural schematic diagram of a computing device 300 provided in an embodiment of the present application.
  • the computing device 300 includes: a processor 310 , a memory 320 , a communication interface 330 , and a bus 340 .
  • the communication interface 330 in the computing device 300 shown in FIG. 20 may be used to communicate with other devices.
  • the processor 310 may be connected to a memory 320.
  • the memory 320 may be used to store the program code and data. Therefore, the memory 320 may be a storage unit inside the processor 310, or an external storage unit independent of the processor 310, or a component including a storage unit inside the processor 310 and an external storage unit independent of the processor 310.
  • the computing device 300 may further include a bus 340.
  • the memory 320 and the communication interface 330 may be connected to the bus 340.
  • the bus 340 is connected to the processor 310.
  • the bus 340 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus 340 may be divided into an address bus, a data bus, a control bus, etc.
  • FIG. 20 only uses one line to represent, but does not mean that there is only one bus or one type of bus.
  • the processor 310 may adopt a central processing unit (CPU).
  • the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • DSP digital signal processors
  • ASIC application-specific integrated circuits
  • FPGA field programmable gate arrays
  • a general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.
  • the processor 310 may adopt one or more integrated circuits to execute relevant programs to implement the technical solutions provided in the embodiment of the present application.
  • the memory 320 may include a read-only memory and a random access memory, and provides instructions and data to the processor 310.
  • a portion of the processor 310 may also include a non-volatile random access memory.
  • the processor 310 may also store information on the device type.
  • the processor 310 executes the computer-executable instructions in the memory 320 to perform the operating steps of the above method.
  • the computing device 300 can correspond to the corresponding subject in the method according to each embodiment of the present application, and the above-mentioned and other operations and/or functions of each module in the computing device 300 are respectively for realizing the corresponding process of each method of the present embodiment, which will not be repeated here for the sake of brevity.
  • the disclosed systems, devices and methods can be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.
  • the technical solution of the present application or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, etc.) to perform operations.
  • the aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.
  • An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon.
  • the program is executed by a processor, the program is used to execute a method for generating diversified questions, which includes at least one of the solutions described in the above embodiments.
  • Computer-readable media can be computer-readable signal media or computer-readable storage media.
  • Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above.More specific examples (non-exhaustive lists) of computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, RAM, ROM, erasable programmable read-only memories, optical fibers, portable compact disk read-only memories (CD-ROMs), optical storage devices, magnetic storage devices, or any suitable combination of the above.
  • computer-readable storage media can be any tangible medium containing or storing programs, which can be used by instruction execution systems, devices or devices or used in combination with them.

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Abstract

一种投影装置、显示设备、运载工具和投影方法。投影装置(100)中设有光学元件，光学元件中的图像产生单元（110）向反射偏光器（120）发射偏振光束，偏振光束经过反射偏光器（120），反射偏光器（120）针对不同偏振态的光具有选择透过性，经由反射偏光器（120）后的偏振光束透过第一偏振转换器（140）后转变偏振状态，并经过曲面镜（130）反射后透过第一偏振转换器（140），第一偏振装换器（140）转换偏振状态，并再次经过反射偏光器（120），两次经过反射偏光器（120）的偏振状态不同。投影装置（100）中的光学元件可选择性对偏振光束进行处理，光路可对空间进行复用，从而使投影装置（100）内部结构紧凑，有效控制投影装置（100）的体积。

Description

投影装置、显示设备、运载工具和投影方法 技术领域
本申请涉及投影成像技术，应用于智能汽车增强显示技术领域，尤其涉及一种投影装置、显示设备、运载工具和投影方法。
背景技术
随着智能汽车市场的发展，增强现实抬头显示(Augmented-Reality-Head-up-Display，AR-HUD)等智能光学显示越来越成为核心器件，AR-HUD是全息增强现实技术(AR)和抬头显示功能(HUD)的结合，通过计算处理将获取的图像信息叠加在行驶路线前方的现实三维环境中，可以将距离、速度和导航等信息融入到驾驶员所获取的现实画面中，计算数据和显示场景相结合，使得数字信息更加的丰富和直观，提升了驾驶体验和驾驶安全。AR-HUD技术正逐步普遍应用于大中小型乘用车、商务车和工程车等车辆中，全面赋能智能座舱性能体验提升。
当前，AR-HUD上车量产的方案为自由曲面方案，即由图像产生单元(Picture generation unit,PGU)产生实焦图像后由两到三块自由曲面成放大100倍以上虚像。在AR-HUD技术中，视场角(Field of view，FOV)和虚像距(Virtual Image Distance，VID)是影响AR-HUD显示技术成像效果的重要参数，FOV和VID越大，数字信息和显示场景的结合程度越高，驾驶者的体验程度越好。
随着FOV(视场角)和VID(虚像距)需求越来越大，导致AR-HUD设备体积增大，比如对于FOV为15×5度，VID为7.5米的AU-HUD而言，体积可在15升左右；对于FOV为20×8度，VID为20米的AU-HUD而言，体积会增大至25升左右。由于汽车内设备容纳空间有限，并且当前AR-HUD设备多设置在方向盘前侧的中控台内，AR-HUD体积的增大必然导致中控台体积的增大，进而影响该大视场角和长虚像距方案的上车使用。因此，AR-HUD设备的小型化成为解决该技术体验增强和上车需求间矛盾的突破点。
发明内容
本申请实施例公开了一种投影装置、运载工具、显示设备和投影方法，本申请提供了一种通过偏振组件实现光束偏振状态的改变，能够在增大投影装置的视场角和虚像距时，对应减小投影装置的体积。
第一方面，本申请实施例公开了一种投影装置，包括：图像产生单元、反射偏光器、第一曲面镜和第一偏振转换器，所述图像产生单元用于发射偏振光束；所述第一偏振转换器位于所述反射偏光器和所述第一曲面镜之间，用于透过并改变所述偏振光束的偏振态；所述第一曲面镜用于处理所述偏振光束；所述偏振光束由所述图像产生单元发出后，经由所述反射偏光器，传播至所述第一偏振转换器，并透过所述第一偏振转换器传播至所述第一曲面镜，经由所述第一曲面镜传播至所述第一偏振转换器，透过所述第一偏振转换器传播至所述反射偏光片。通过设置图像产生单元发出偏振光束，并通过反射偏光器、第一偏振转换器和曲面反射镜对光束偏振状态的不同响应，以使得光束在反射偏光器和曲面镜之间往返传输时，选 择性的被反射偏光器透射和反射，反射偏光器不需要对往返传输的光束进行避让，投影装置的体积相应降低，在增大投影装置的FOV和VID时，有效控制投影装置体积少量增加、体积不变或者体积减小。
结合第一方面，在第一方面的一种可能的实施方式中，所述反射偏光器用于透过偏振状态为第一状态的偏振光束和反射偏振状态为第二状态的偏振光束；所述偏振态包括线偏振光和圆偏振光，所述第一状态的偏振光束包括第一状态线偏振光和第一状态圆偏振光，所述第二状态的偏振光束包括第二状态线偏振光和第二状态圆偏振光。通过反射偏光器对不同状态偏振光束的选择透过性，反射偏光器不需要对往返传输的光束进行避让，投影装置的体积相应降低。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器靠近所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；所述偏振光束经由所述反射偏光器反射，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并透过所述第一偏振转换器传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述偏振光束的偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。通过设置反射偏光器、曲面镜和第一偏振转换器的相应参数，光束可先被反射偏光器反射，反射后的光束经曲面镜和第一偏振转换器转变偏振状态，再透过反射偏光器，使得反射偏光器和图像产生单元可在中控台内沿纵向排布，减小投影装置的横向尺寸。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一偏振转换器包括1/4波片。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器靠近所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并经由所述反射偏光器反射，其偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光并传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述第一曲面反射镜反射的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态圆偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。通过设置反射偏光器、曲面镜和第一偏振转换器的相应参数，反射偏光器可反射第二状态圆偏振光，透过第一状态圆偏振光，投影装置可选择透过更多状态的偏振光。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一曲面镜包括自由曲面透反镜，所述图像产生单元位于所述自由曲面透反镜背离所述反射偏光器的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；所述偏振光束透过所述自由曲面透反镜，透过所述自由曲面透反镜的偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并经由所述反射偏光器反射，其偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光并传播至所述自由曲面透反镜，所述偏振光束经所述自由曲面透反镜反射，所述自由曲面透反镜反射的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第 一偏振转换器，其偏振态转换为第一状态圆偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。曲面镜由自由曲面透反镜构成，曲面镜也具有偏振状态光束的选择透过性，在设置时曲面镜可不避让入光光束，进一步缩小投影装置的体积。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器背离所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；所述偏振光束透过所述反射偏光器，透过所述反射偏光器的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并透过所述第一偏振转换器传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述偏振光束的偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，偏振光束经所述反射偏光器反射出所述投影装置。反射偏光器先透过光束，透过的光束经过曲面镜和第一偏振转换器进行偏振状态的改变，再经过反射偏光器反射出投影装置，反射偏光器不需避让折返光束，有效缩小投影装置的体积。
结合第一方面，在第一方面的一种可能的实施方式中，所述投影装置还包括第二偏振转换器，所述投影装置还包括第二偏振转换器，所述第二偏振转换器位于所述反射偏光器远离所述第一曲面反射镜的一侧，所述第二偏振转换器用于将经由所述反射偏振器射出的所述偏振光束由圆偏振光转换为线偏振光。以使得投影装置向外发出线偏振光，并和投影装置中图像产生单元发出入光光束的偏振类型相统一。
结合第一方面，在第一方面的一种可能的实施方式中，所述第二偏振转换器包括1/4波片或1/2波片。
结合第一方面，在第一方面的一种可能的实施方式中，所述第一偏振转换器包括1/4波片或1/2波片。
结合第一方面，在第一方面的一种可能的实施方式中，所述反射偏光器包括偏光元件，所述偏光元件包括液晶偏振器或反射偏光片中至少一个。其中液晶偏振器可通过液晶材料的电压控制，通过液晶旋转来实现不同圆偏振光状态的选择性透过。
结合第一方面，在第一方面的一种可能的实施方式中，所述反射偏光器还包括基底层，所述偏光元件贴合设置于所述基底层，以在投影装置中承载反射偏光器，防止反射偏光器振动而造成图像的晃动。
结合第一方面，在第一方面的一种可能的实施方式中，所述投影装置还包括透镜元件，所述透镜元件位于所述投影装置的光束出射端，所述透镜元件用于调整出射光束的光路。透镜元件可以对投影装置出射的光束进行光学调整，提高投影装置整个架构的光学质量，以降低曲面镜中自由曲面设计加工的难度。并且，在现有的投影装置生产过程中，各个模块为标准化制备，在面对不同车型等不同的光学需求时，可以通过设计透镜元件的加工参数，就可以满足投影装置的多个性能，降低投影装置的整体开发难度和成本。
投影装置中的光学设计是基于性能指标、材料选用、可测试验收、公差控制、加工装配以及成本等进行确定或优化，这些考虑因素要贯穿产品设计的开始到生成产品的结束，以及在产品应用中的设备调试过程。在整个过程中，特别针对抬头显示装置，自由曲面镜的设计参数对整个产品的成像质量影响较大，而自由曲面镜的参数设计和产品制备对工艺有较高要求。本申请提出在自由曲面实现的同等指标情况下，增加透镜元件就相当于增加光学设计的优化维度，通过调节透镜元件的参数设计可优化投影装置的成像，对自由曲面指标的要求降 低；同时，改变透镜元件可满足投影装置的一定性能指标要求，进而可不用改变自由曲面，降低了光学系统优化的难度和复杂度。
结合第一方面，在第一方面的一种可能的实施方式中，所述投影装置还包括匀光元件，所述匀光元件位于所述图像产生单元的出光侧，所述匀光元件用于实现图像产生单元的投影像面。匀光元件能够接收图像产生单元的实像，并对图像进行匀光和光学扩展角控制，为投影装置中偏振折叠组件提供显示物面。
结合第一方面，在第一方面的一种可能的实施方式中，所述投影装置还包括防眩光膜，所述防眩光膜用于处理所述偏振光束，减轻或防止眩光。防眩光膜能够改变光线反射的对称中心，在外界的太阳光透过挡风玻璃进入到投影装置内时，太阳光经防眩光膜反射后的光线偏离驾驶员的眼睛可视范围，例如偏离至驾驶员眼睛的上方，而不会进入到驾驶员的眼睛中，以避免造成驾驶员眩晕不适。
第二方面，本申请实施例提供了一种显示设备，包括成像屏和上述任一项所述的投影装置，所述成像屏用于承接所述投影装置所发出的光并成像。
结合第二方面，在第二方面的一种可能的实施方式中，所述显示设备包括全息眼镜和/或头盔。
第三方面，本申请实施例公开了一种运载工具，包括挡风玻璃和上述任一项所述的投影装置或显示设备，所述运载工具包括投影介质，所述投影介质用于承接所述投影装置所发出的光并成像。
第四方面，本申请实施例公开了一种投影方法，应用于投影装置，所述投影装置包括，图像产生单元、反射偏光器、第一曲面镜和第一偏振转换器；所述方法包括：
所述图像产生单元发射偏振光束，所述偏振光束经由所述反射偏光器，传播至所述第一偏振转换器，并透过所述第一偏振转换器传播至所述第一曲面镜，经由所述第一曲面镜传播至所述第一偏振转换器，透过所述第一偏振转换器传播至所述反射偏光片，并经由所述反射偏光器，投射出所述投影装置。
需要说明的是，本申请第二方面、第三方面和第四方面的部分可能实施方式与第一方面的部分实施方式构思一致，其所带来的有益效果可以参考第一方面的有益效果，因此不再赘述。
附图说明
以下对本申请实施例用到的附图进行介绍。
图1是视场角示意图；
图2是虚像距示意图；
图3是本申请实施例提供的一种投影装置在汽车领域中的应用场景示意图；
图4是本申请实施例提供的一种投影装置在汽车领域中的应用场景的另一视角的示意图；
图5是本申请实施例提供的一种投影装置在汽车领域中将图像投射到驾驶员眼中的成像示意图；
图6是本申请实施例提供的一种投影装置在汽车领域中应用的光路示意图；
图7是本申请实施例提供的一种投影装置在抬头显示领域应用的光束传输示意图；
图8是本申请实施例提供的一种投影装置的光束偏振状态变化示意图；
图9是本申请实施例提供的一种投影装置在抬头显示领域应用的另一种光束传输示意图；
图10是本申请实施例提供的一种投影装置的光束偏振状态另一种变化示意图；
图11是本申请实施例提供的一种投影装置在抬头显示领域应用的另一种光束传输示意图；
图12是本申请实施例提供的一种投影装置的光束偏振状态另一种变化示意图；
图13是本申请实施例提供的一种投影装置在抬头显示领域应用的另一种光束传输示意图；
图14是本申请实施例提供的一种投影装置的光束偏振状态另一种变化示意图；
图15是本申请实施例提供的一种投影装置中设置透镜元件的示意图；
图16是本申请实施例提供的一种投影装置中设置匀光元件的示意图；
图17是本申请实施例提供的一种投影装置中设置防眩光膜的示意图；
图18是本申请实施例提供的一种投影装置中设置处理器的示意图；
图19是本申请实施例提供的一种投影装置中两个曲面镜的示意图；
图20是本申请实施例提供的一种计算设备的结构性示意性图。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。需要说明的是，本申请中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其他实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。
本申请中使用的术语“包括”不应解释为限制于其后列出的内容；它不排除其它的元件。因此，其应当诠释为指定所提到的所述特征、整体或部件的存在，但并不排除存在或添加一个或更多其它特征、整体或部件及其组群。
本申请中实施例提到的“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a、b、或c中的至少一项(个)，可以表示：a、b、c、(a和b)、(a和c)、(b和c)、或(a和b和c)，其中a、b、c可以是单个，也可以是多个。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A、同时存在A和B、单独存在B这三种情况，其中A、B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。
以及，除非有相反的说明，本申请实施例使用“第一”、“第二”等序数词是用于对多个对象进行区分，不用于限定多个对象的顺序、时序、优先级或者重要程度。例如，第一分光装置和第二分光装置，只是为了区分不同的分光装置，而并不是表示这两种装置的结构、探测原理、重要程度等的不同。
本说明书中提到的“一个实施例”或“实施例”意味着与该实施例结合描述的特定特征、结构或特性包括在本发明的至少一个实施例中。因此，在本说明书各处出现的用语“在一个实施例中”或“在实施例中”并不一定都指同一实施例，但可以指同一实施例。此外，在一个或多个实施例中，能够以任何适当的方式组合各特定特征、结构或特性，如从本公开对本领域的普通技术人员显而易见的那样。
为了便于理解，下面先对本申请实施例中的部分用语进行解释说明。
视场角(Field of view，FOV)，又称作视场，指的是显示图像的边缘到图像获取中心的最大立体夹角。例如，在光学测量设备中，以光学测量设备的镜头中心为图像获取中心，以光学测量设备测量的目标物像可通过镜头，并且透过镜头中呈现最大范围两条边缘构成的夹角为视场角。以及，在投影设备中，投影设备在成像机构上投影图像的两侧边缘和投影设备镜头中心点之间的夹角为视场角，通常为距离最大的两个边缘点。在抬头显示领域中，图像获取中心为人体的瞳孔。在投影领域，FOV一般包括垂直视场角、水平视场角和对角线视场角。参阅图1所示，图1中的O点为图像获取中心，ABCD所围合的四边形为投影成像，OA连线和OB连线之间的夹角可以为水平视场角，OB连线和OC连线的夹角可以为垂直视场角，OA连线和OC连线之间的夹角可以为对角视场角。在没有特殊说明时，默认的视场角一般都是水平视场角和垂直视场角。
虚像距(Virtual Image Distance，VID)，又称虚像距离，指的是投影的虚像到图像获取中心的距离。其中，在抬头显示领域中，图像获取中心为人体的瞳孔。参阅图2所示，在抬头显示系统中，虚像距为人体瞳孔到虚拟成像之间的直线距离。
图3示出了本申请实施例提供的一种投影装置100在汽车领域中的应用场景示意图。图4示出了本申请实施例提供的一种投影装置100在汽车领域中的应用场景的另一视角的示意图。图5示出了本申请实施例提供的一种投影装置100在汽车领域中将图像投射到驾驶员眼中的成像示意图，其示出了图3和图4中的投影装置100将图像投射到驾驶员眼中，使驾驶员能够看到的虚像信息。当驾驶员透过挡风玻璃200望向车外时，能够看到具有一定景深(即图像焦点前后的范围内所呈现的清晰图像的距离)的虚像。其中，通过摄像头和红外传感器等信息获取模块来获取汽车前方信息，前方道路信息包括前车车距、前车车速和道路信息等，并且将相应的数字信息以成像的方式投影到和前车环境信息紧密结合，其中数字信息包括：汽车车速、导航信息(道路指示)、汽车档位、定速巡航、前车车距、前车车速、转速信息、电量信息、续航里程信息、影音娱乐系统信息等，从而使驾驶员在驾驶车辆1时不需要转移视线就能够了解驾驶车辆1所需的信息。避免驾驶员驾驶车辆1时，例如低头查看仪表盘或者中控屏信息，可能导致无法顾及路况而引发的驾驶风险。为实现上述投影，汽车需要具备抬头显示系统(Head Up Display，HUD)，其中增强抬头显示系统可以包括投影装置100以及光学元件，投影装置100可以投射图像，光学元件可以包括车辆的挡风玻璃200，或者贴附在挡风玻璃200上的反射膜，又或者单独设置于汽车座舱内屏幕。光学元件可以将投影装置100投射出的图像进行反射和/或折射后投射到驾驶员的眼中，以使得驾驶员可以获得挡风玻璃200前方的虚拟信息图像。
在抬头显示领域中，视场角可以为15×5度。其中，15度指的是水平视场角为15度，参阅图1所示，可以为OA连线和OB连线之间的夹角；5度指的是垂直视场角，可以为OB连线和OC连线的夹角。正常来说，一个人的视网膜尺寸是有限的，通常人们双眼的FOV一般在90度至120度(可以为水平视场角，也可以为垂直视场角)之间，并且通过双眼视差，人眼可以感知物体的3D状态。投影装置对应FOV的增大，能够提高虚拟图像和现实图像的拟合程度，提高虚拟图像的覆盖面积，驾驶员的视觉效果也相应提高。
在抬头显示领域中，VID可以为7.5米。其中，参阅图2所示，VID可以为车辆前侧成像距离驾驶者眼睛的距离。投影装置对应VID的增大，能够提高虚拟图像相对于驾驶员的视野深度，以使得虚拟图像和远处的现实图像拟合程度更高，虚拟图像的立体效果更加逼真。并且，VID的增大，驾驶员查看显示图像信息和虚拟图像信息时不需要频繁变焦，提高了驾 驶员的用眼舒适度，也相应增大了驾驶安全性。
图6示出了一种投影装置100在汽车领域中应用的光路示意图。其中，图像产生单元110发出光束至反光镜190，图像产生单元110发出的光束截面积逐渐增大，并被反光镜190反射放大至第一曲面镜130处，第一曲面镜130将光束反射至挡风玻璃200处，光束经挡风玻璃200反射至驾驶员的眼睛中。其中，第一曲面镜130根据投影装置100内部结构、安装位置、挡风玻璃的显示区域处形状等因素进行参数选择，以校正和补偿挡风玻璃不同投影区域的曲率和光路长度不一样而产生的光学畸变。
其中，若增大投影装置100的FOV，需要增加投影装置100中的光路传输距离以增大放大系数，并且反光镜190和第一曲面镜130所反射光束的尺寸增大，反光镜190和第一曲面镜130的尺寸相应增大。若在保证图像质量的前提下增大投影装置100的VID，需要增加投影装置100中的光路传输距离。不论是增大FOV，还是增大VID，都会导致投影装置100的体积增大。例如，对于FOV为15×5度，VID为7.5米的投影装置100而言，体积多在15升左右；对于FOV为20×8度，VID为20米的投影装置100而言，体积可达到25升，体积增大将近一倍。
在汽车领域中，实现增强抬头显示功能的投影装置100多设置在汽车的中控台处。参阅图3和图4所示，投影装置100可设置在中控台内，并且位于方向盘的前侧(匹配于汽车行驶方向的前方)。中控台内器件数量较多，中控台的整体尺寸有限，不适宜内置较大体积的投影装置100，体积的限制导致目前抬头显示领域内FOV和VID无法达到较大范围，影响成像质量。
需要说明的是，本申请实施例中的车辆皆以汽车为例进行示例性的说明，不应视为对本申请实施例的限制。车辆可以是传统的燃油汽车，也可以是纯电动汽车、混动汽车等新能源汽车。车辆可以是轿车、货车、客运客车、运动型多用途汽车(sport utility vehicle，SUV)等不同类型汽车中的任意一种，还可以是三轮车、摩托车、火车等载人或者载货的陆地运输装置。或者，本申请的投影装置还可以应用于飞机、船舶等其他类型的运载工具中。
为了解决FOV和VID增大而导致投影装置100体积增大，难以装载于汽车的问题，本申请提供一种投影装置，参阅图7和图8所示，投影装置100包括图像产生单元110、反射偏光器120、第一曲面镜130和第一偏振转换器140。其中，第一曲面镜130可以采用球面镜，也可以采用非球面镜，也可以为自由曲面镜。第一曲面镜130具有反射功能，能够反射所有偏振光束，也可反射部分偏振光束。本实施方式中，第一曲面镜130以自由曲面镜为例。
其中，图像产生单元110向反射偏光器120发射光束，光束为偏振光束。其中，偏振光束包括多种状态，例如线偏振光和圆偏振光。
线偏振光，指的是光矢量只沿一个固定的方向振动，在光的传播方向上，光矢量的振动处于一个平面上。其中，线偏振光具有不同的偏振形态，例如第一状态线偏振光和第二状态线偏振光等。第一状态线偏振光和第二状态线偏振光的振动方向不同，例如，第一状态线偏振光可以为P线偏振光，第二状态线偏振光可以为S线偏振光，P线偏振光的振动方向和S线偏振光的振动方向相垂直。可以理解的是，本实施方式仅为了区别不同形态的线偏振光，“第一”和“第二”并不构成对线偏振光形态的限定，第一状态线偏振光也可以为S线偏振光，第二状态线偏振光也可以为P线偏振光。
圆偏振光，指的是电矢量沿光束传输方向描绘出圆轨迹的光。圆偏振光具有不同的偏振形态，例如第一状态圆偏振光和第二状态圆偏振光等。第一状态圆偏振光和第二状态圆偏振光的旋转方向不同，例如，第一状态圆偏振光可以为右旋圆偏振光，第二状态圆偏振光可以 为左旋圆偏振光；迎着光线方向看，凡电矢量顺时针旋转的称右旋圆偏振光，凡逆时针旋转的称左旋圆偏振光。可以理解的是，本实施方式为了仅区别不同形态的圆偏振光，“第一”和“第二”并不构成对圆偏振光形态的限定，第一状态圆偏振光也可以为左旋圆偏振光，第二状态圆偏振光也可以为右旋圆偏振光。
图像产生单元110发射的光束在反射偏光器120和第一曲面镜130之间往返传输，第一偏振转换器140位于反射偏光器120和第一曲面镜130之间，在反射偏光器120和第一曲面镜130之间往返传输的光束可透过第一偏振转换器140。第一偏振转换器140可转变透过光束的偏振状态，例如将线偏振光转变为圆偏振光，或者将圆偏振光转变为线偏振光。
图像产生单元110是产生实像单元，也称作图像产生单元(picture generation unit，PGU)，主要包括微显示器(LCoS、DLP、LBS和MicroLED等)、照明光源及系统(照明光源可为LED或Laser，也可以为两者组合)和成像透镜单元等。
反射偏光器120为具有偏振状态选择透过性的偏振器件，反射偏光器120可透射第一状态偏振光，并反射第二状态偏振光。例如，反射偏光器120的偏振方向和P线偏振光的振动方向一致，当图像产生单元110发射出的光束为S线偏振光时，反射偏光器120反射S线偏振光，反射后的S线偏振光经过第一偏振转换器140转变为圆偏振光。第一曲面镜130可反射圆偏振光并转变圆偏振光的旋转方向，光束再次经过第一偏振转换器140时可转变为P线偏振光，此时P线偏振光可透过反射偏光器120，并穿过反射偏光器120传输到投影装置100的外部。
或者，反射偏光器120的偏振方向和S线偏振光的振动方向一致，当图像产生单元110发射出的光束为S线偏振光时，反射偏光器120透过S线偏振光，透射后的S线偏振光经过第一偏振转换器140转变为圆偏振光。第一曲面镜130可反射圆偏振光并转变圆偏振光的旋转方向，光束再次经过第一偏振转换器140时可转变为P线偏振光，此时P线偏振光被反射偏光器120反射，并被反射传输到投影装置100的外部。本实施例仅以该两种方式描述本申请根据反射偏光器120的偏振状态选择透过性来实现FOV和VID的增大，并且控制投影装置100的整体体积增大量，不限定本申请仅可以上述两种方式来实现，其余的实施方式部分在下文陈述。
本申请所述的反射偏光器120包括偏光元件，偏光元件可以为反射偏光片，反射偏光片具有偏振状态选择透过性，并且第一偏振转换器140对图像产生单元110发出的偏振光状态进行改变；当入射第一曲面镜130的光束为圆偏振光时，第一曲面镜130也可改变圆偏振光的偏振形态。通过第一偏振转换器140和第一曲面镜130的组合作用，将反射偏光器120和第一曲面镜130之间的偏振光状态和形态进行转变，以使得光束以不同的偏振状态传输至反射偏光器120时，第一状态偏振光能够透过反射偏光器120，第二状态偏振光被反射偏光器120反射；在投影装置100的光路设计时，反射偏光器120不必避让往返传输的光束，往返传输的光束指的是反射偏光器120和第一曲面镜130之间的光束。
在增大投影装置100的FOV和VID时，反射偏光器120和第一曲面镜130的面积相应增大，光束传输距离(图像产生单元110、反射偏光器120和第一曲面镜130之间的间距增大)也对应增长；反射偏光器120不必避让往返传输的光束，以平衡，反射偏光器120和第一曲面镜130面积增大导致的投影装置100体积增大，以及光束传输距离增长导致的投影装置100体积增大，实现投影装置100体积少量增加、体积不变或者体积减小。
一种可能的实施方式中，参阅图7和图8所示，图7示出了本实施方式中投影装置100在抬头显示领域应用的光束传输示意图，图8示出了本实施方式中投影装置100的光束偏振 状态变化示意图。
图像产生单元110位于反射偏光器120的下方，其中下方参照汽车在正常行驶状态时所对应的方向，投影装置100整体位于中控台内，中控台位于挡风玻璃200的下方。图7中的下方为Y方向，对应汽车行驶状态下的下方；图7中的右方为X方向，对应汽车行驶状态下的后方。参阅图7所示，图像产生单元110位于反射偏光器120的Y方向并向X方向偏移，图像产生单元110朝向反射偏光器120发出入光光束111，入光光束111为图像产生单元110发出并首次和反射偏光器120接触的光束，入光光束111为第二状态线偏振光。
本实施方式中，参阅图8所示，第二状态线偏振光以S线偏振光为例，图8中呈右上左下方向倾斜的双向箭头表示S线偏振光，呈现S线偏振的入光光束111经反射偏光器120反射后，形成第一折返光束112。第一折返光束112为S线偏振光，在透过第一偏振转换器140后，转变为第二状态圆偏振光，本实施方式中第二状态圆偏振光以左旋圆偏振光为例，图8中逆时针方向弧形箭头表示左旋圆偏振光，呈左旋圆偏振状态的第一折返光束112经第一曲面反射镜131反射后，形成第二折返光束113。
请参考图7，经光学元件处理后的光束可部分再次经过反射偏光器120，部分不再经过反射偏光器120；请参考图8，经处理后的光束也可全部再次经过反射偏光器120，本申请对光束经处理后经过反射偏光器的量不做限制。
本实施方式中，第一曲面镜130包括第一曲面反射镜131，本实施例以自由曲面反射镜为例，以矫正挡风玻璃的不规则曲面带来的像差。在传统光学设计中所采用的光学元件的面型为标准球面，一般需要多片球面镜进行配合矫正像差，从而导致其光学结构比较复杂，占用空间较大。随着光学产业的发展，面型较为复杂的非球面的设计与制造技术到得到了很大提高，非球面一般是指具有回转轴的抛物面、椭球面、渐开面、双曲面等二次曲面以及高次曲面，还有非回转非球面，如离轴非球面。根据使用场景的不同，一片非球面通常可以代替两片或多片球面矫正像差，从而简化光学结构，实现光路的微型化与轻量化。
相对于非球面，自由曲面是一种面型更为复杂的光学结构，其表面各点的曲率半径都不相同，面型的自由度非常高。自由曲面不仅能够代替多片非球面矫正像差，还能最大限度的提高光学质量，精简光学结构。光学自由曲面面形结构复杂，自由度高，没有明确的表达式定义，一般认为不具备全局的旋转对称性、无统一的光轴、整个表面存在多个曲率半径的光学表面为光学自由曲面。
第一曲面反射镜131反射后的第二折返光束113转变成右旋圆偏振光，图8中顺时针方向弧形箭头表示右旋圆偏振光，右旋圆偏振光透过第一偏振转换器140后转变为P线偏振光，图8中呈左上右下方向倾斜的双向箭头表示P线偏振光。呈P线偏振的第二折返光束113可透过反射偏光器120，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
比较图7和图6所示，本实施方式通过设置图像产生单元110发出偏振光束，并通过反射偏光器120、第一偏振转换器140和第一曲面反射镜131对光束偏振状态的不同响应，以使得光束在反射偏光器120和第一曲面反射镜131之间往返传输时，选择性的被反射偏光器120透射和反射，反射偏光器120不需要对往返传输的光束进行避让，投影装置100的体积相应降低，在增大投影装置100的FOV和VID时，有效控制投影装置100体积少量增加、体积不变或者体积减小。
可以理解的是，本实施方式所述的第二状态线偏振光还可以为P线偏振光，呈现P线偏振的入光光束111经反射偏光器120反射后，形成第一折返光束112。第一折返光束112为P线偏振光，在透过第一偏振转换器140后，转变为第二状态圆偏振光，第二状态圆偏振光可 以为右旋圆偏振光，呈右旋圆偏振状态的第一折返光束112经第一曲面反射镜131反射后，形成第二折返光束113。
第一曲面反射镜131反射后的第二折返光束113转变成左旋圆偏振光，左旋圆偏振光透过第一偏振转换器140后转变为S线偏振光，呈S线偏振的第二折返光束113可透过反射偏光器120，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
本实施方式中，反射偏光器120可以为具有偏振特性的反射偏光片，可采用两种不同折射率材料组成多层膜，如增亮膜(dual brightness enhancement film，DBEF)，具体可以为反射型偏光增亮膜，由多层组成，例如扩散层、多层反射型偏光片和扩散层等依次层叠形成。具体地，反射偏光片可单独贴合设置于基底层，所述基底层可以为聚碳酸酯(PC)或玻璃基板。其中，第一偏振转换器140的尺寸，以及反射偏光片和第一偏振转换器140的间距，可根据投影装置100的光学系统架构来设计相对应的参数，以保证光束在不同的口径下全通过，确保第一偏振转换器140的整个尺寸得到有效的利用。并且，反射偏光器120和第一曲面反射镜131的间距设计也根据投影装置100的光学系统架构来设计。
第一偏振转换器140可以为1/4波片(quarter wave plate，QWP)，也可以为1/2波片(half wave plate，HWP)。波片是由晶体制作的平行平面薄片，材料可以是沿平行于水晶或方解石等双折射晶体的光轴而切下的一片晶片，或者为对入射光具有传播方向性的云母片、玻璃纸或聚乙烯醇等材料制成。具体地，波片可以和第一曲面反射镜131的反射表面贴合，或者单独贴合在聚碳酸酯(PC)或玻璃基板上。
一种可能的实施方式中，参阅图9和图10所示，图9示出了本实施方式中投影装置100在抬头显示领域应用的另一种光束传输示意图，图10示出了本实施方式中投影装置100的光束偏振状态另一种变化示意图。
图像产生单元110位于反射偏光器120的下方，其中下方参照汽车在正常行驶状态时所对应的方向，投影装置100整体位于中控台内，中控台位于挡风玻璃的下方。图9中的下方为Y方向，对应汽车行驶状态下的下方；图9中的右方为X方向，对应汽车行驶状态下的后方。参阅图9所示，图像产生单元110位于反射偏光器120的Y方向并向X方向偏移，图像产生单元110朝向反射偏光器120发出入光光束111，入光光束111为图像产生单元110发出并首次和反射偏光器120接触的光束。
本实施方式中，参阅图10所示，第二状态偏振光以左旋圆偏振光为例，图像产生单元110发出呈S线偏振状态的入光光束111，图10中呈右上左下方向倾斜的双向箭头表示S线偏振光，呈现S线偏振的入光光束111先透过第一偏振转换器140而转变成左旋圆偏振光，图10中逆时针方向弧形箭头表示左旋圆偏振光；其中左旋圆偏振光为本实施方式所述的第二状态偏振光，左旋圆偏振光经反射偏光器120反射后转变成右旋圆偏振光，图10中顺时针方向弧形箭头表示右旋圆偏振光，形成第一折返光束112。第一折返光束112为右旋圆偏振光，在透过第一偏振转换器140后，转变为第一状态线偏振光，本实施方式中第一状态圆偏振光以P线偏振光为例，图10中呈左上右下方向倾斜的双向箭头表示P线偏振光，呈P线偏振状态的第一折返光束112经第一曲面反射镜131反射后，形成第二折返光束113。
本实施方式中，第一曲面镜130包括第一曲面反射镜131，本实施例以自由曲面反射镜为例，以矫正挡风玻璃的不规则曲面带来的像差。
第一曲面反射镜131反射后的第二折返光束113呈P线偏振状态，P线偏振状态的第二折返光束113透过第一偏振转换器140而转变成第一状态偏振光，右旋圆偏振光为本实施方式所述的第一状态偏振光，右旋圆偏振光可透过反射偏光器120，并经过挡风玻璃200反射 后在驾驶员的眼睛内成像。
可以理解的是，本实施方式所述的第二状态偏振光还可以右旋圆偏振光为例，图像产生单元110发出呈P线偏振状态的入光光束111，P线偏振光透过第一偏振转换器140后转变为第二状态偏振光，例如第二状态偏振光可以为右旋圆偏振光，右旋圆偏振光经反射偏光器120反射后，形成第一折返光束112。第一折返光束112为左旋圆偏振光，在透过第一偏振转换器140后，转变为第一状态线偏振光，第一状态线偏振光可以为P线偏振光，呈P线偏振状态的第一折返光束112经第一曲面反射镜131反射后，形成第二折返光束113。
第一曲面反射镜131反射后的第二折返光束113呈P线偏振状态，P线偏振光透过第一偏振转换器140后转变为右旋圆偏振光，呈右旋圆偏振状态的第二折返光束113可透过反射偏光器120，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
本实施方式中，反射偏光器120包括偏光元件，偏光元件可以为具有偏振特性的液晶偏振器。其中，液晶偏振器可通过控制电压实现液晶偏转，实现左旋圆偏振光反射与右旋圆偏振光透过，或者实现右旋圆偏振光反射与左旋圆偏振光透过。液晶偏振器可贴合设置于基底层，基底层可以为聚碳酸酯(PC)或玻璃基板。其中，第一偏振转换器140的尺寸，以及液晶偏振器和第一偏振转换器140的间距，可根据投影装置100的光学系统架构来设计相对应的参数，以保证光束在不同的口径下全通过，确保第一偏振转换器140的整个尺寸得到有效的利用。并且，反射偏光器120和第一曲面反射镜131的间距设计也根据投影装置100的光学系统架构来设计。
第一偏振转换器140可以为1/4波片(quarter wave plate，QWP)，也可以为1/2波片(half wave plate，HWP)。波片是由晶体制作的平行平面薄片，材料可以是沿平行于水晶或方解石等双折射晶体的光轴而切下的一片晶片，或者为对入射光具有传播方向性的云母片、玻璃纸或聚乙烯醇等材料制成。具体地，波片可以和第一曲面反射镜131的反射表面贴合，或者单独贴合在聚碳酸酯(PC)或玻璃基板上。
可以理解的是，第一偏振转换器140的波片可以为一个整体，如图9所示的一个整体波片，同时透过入光光束111、第一折返光束112和第二折返光束113。或者，第一偏振转换器140的波片可以为两个部分，分别设置在反射偏光器120和图像产生单元110之间以透过入光光束111，以及设置在反射偏光器120和第一曲面反射镜131之间以透过第一折返光束112和第二折返光束113。
以及，在图9所示的投影装置100中，投影装置100还可以包括第二偏振转换器150，第二偏振转换器150设置在反射偏光器120背离第一曲面反射镜131的一侧，并且反射偏光器120透过的圆偏振光可透过第二偏振转换器150，第二偏振转换器150将圆偏振光转变为线偏振光，线偏振光可经过挡风玻璃200反射后在驾驶员的眼睛内成像。
一种可能的实施方式中，参阅图11和图12所示，图11示出了本实施方式中投影装置100在抬头显示领域应用的另一种光束传输示意图，图12示出了本实施方式中投影装置100的光束偏振状态另一种变化示意图。
本实施方式与上述实施方式相比，入光光束111可先透过反射偏光器120，透过反射偏光器120的入光光束111在反射偏光器120和第一曲面镜130之间往返传输，并可通过反射偏光器120反射出投影装置100。
具体地，参阅图11和图12所示，图像产生单元110可以位于反射偏光器120的右方，其中右方参照汽车在正常行驶状态时所对应行驶方向的后侧方向。投影装置100整体位于中控台内，中控台位于挡风玻璃的下方。图11中的下方为Y方向，对应汽车行驶状态下的下 方；图11中的右方为X方向，对应汽车行驶状态下相对行驶方向的后方。参阅图11所示，图像产生单元110位于反射偏光器120的X方向并向Y方向偏移，图像产生单元110朝向反射偏光器120发出入光光束111，入光光束111为图像产生单元110发出并首次和反射偏光器120接触的光束。
本实施方式中，参阅图12所示，第一状态线偏振光以S线偏振光为例，图12中呈右上左下方向倾斜的双向箭头表示S线偏振光，图像产生单元110发出S线偏振光，呈现S线偏振状态的入光光束111经反射偏光器120透射后，形成透射光束114。透射光束114为S线偏振光，在透过第一偏振转换器140后，转变为第一状态圆偏振光，本实施方式中第一状态圆偏振光以左旋圆偏振光为例，图12中逆时针方向弧形箭头表示左旋圆偏振光，呈左旋圆偏振状态的透射光束114经第一曲面反射镜131反射后，形成第一折返光束112。
本实施方式中，第一曲面镜130包括第一曲面反射镜131，本实施例以自由曲面反射镜为例，以矫正挡风玻璃的不规则曲面带来的像差。
第一曲面反射镜131反射后的第一折返光束112转变成右旋圆偏振光，图12中顺时针方向弧形箭头表示右旋圆偏振光，右旋圆偏振光透过第一偏振转换器140后转变为P线偏振光，图12中呈左上右下方向倾斜的双向箭头表示P线偏振光。呈P线偏振状态的第一折返光束112被反射偏光器120，本实施方式中的第二状态线偏振光可以为P线偏振光，并形成第二折返光束113。本实施方式中，为了防止第二折返光束113再次被第一曲面反射镜131反射，反射偏光器120呈倾斜设置，具体地呈左下右上方向倾斜，以使得第二折返光束113能够避开反射偏光器120以及第一偏振转换器140。呈P线偏振的第二折返光束113射出投影装置100，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
可以理解的是，本实施方式所述的第二状态线偏振光还可以为S线偏振光，第一状态线偏振光还可以为P线偏振光，入光光束111呈现P线偏振状态，入光光束111经反射偏光器120透射后，形成透射光束114。透射光束114为P线偏振光，在透过第一偏振转换器140后，转变为第一状态圆偏振光，第一状态圆偏振光可以为右旋圆偏振光，呈右旋圆偏振状态的透射光束114经第一曲面反射镜131反射后，形成第一折返光束112。
第一曲面反射镜131反射后的第一折返光束112转变成左旋圆偏振光，左旋圆偏振光透过第一偏振转换器140后转变为S线偏振光，呈S线偏振的第一折返光束112被反射偏光器120反射，形成S线偏振状态的第二折返光束113，第二折返光束113射出投影装置100，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
本实施方式中，反射偏光器120可以为具有偏振特性的反射偏光片，可采用两种不同折射率材料组成多层膜，如增亮膜(dual brightness enhancement film，DBEF)，具体可以为反射型偏光增亮膜，由多层组成，例如扩散层、多层反射型偏光片和扩散层等依次层叠形成。具体地，反射偏光片可单独贴合设置于基底层，基底层可以为聚碳酸酯(PC)或玻璃基板。其中，第一偏振转换器140的尺寸，以及反射偏光片和第一偏振转换器140的间距，可根据投影装置100的光学系统架构来设计相对应的参数，以保证光束在不同的口径下全通过，确保第一偏振转换器140的整个尺寸得到有效的利用。并且，反射偏光器120和第一曲面反射镜131的间距设计也根据投影装置100的光学系统架构来设计。
第一偏振转换器140可以为1/4波片(quarter wave plate，QWP)，也可以为1/2波片(half wave plate，HWP)。波片是由晶体制作的平行平面薄片，材料可以是沿平行于水晶或方解石等双折射晶体的光轴而切下的一片晶片，或者为对入射光具有传播方向性的云母片、玻璃纸或聚乙烯醇等材料制成。具体地，波片可以和第一曲面反射镜131的反射表面贴合，或者单 独贴合在聚碳酸酯(PC)或玻璃基板上。
一种可能的实施方式中，参阅图13和图14所示，图13示出了本实施方式中投影装置100在抬头显示领域应用的另一种光束传输示意图，图14示出了本实施方式中投影装置100的光束偏振状态另一种变化示意图。
本实施方式与上述实施方式相比，入光光束111可先透过第一曲面镜130，再通过反射偏光器120反射，反射偏光器120反射的光束在反射偏光器120和第一曲面镜130之间往返传输，并可透过反射偏光器120射出投影装置100。
具体地，参阅图13和图14所示，图像产生单元110可以位于反射偏光器120的下方，第一曲面镜130位于反射偏光器120和图像产生单元110之间，第一偏振转换器140位于反射偏光器120和第一曲面镜130之间。其中下方参照汽车在正常行驶状态时所对应的方向，投影装置100整体位于中控台内，中控台位于挡风玻璃的下方。图13中的下方为Y方向，对应汽车行驶状态下的下方；图13中的右方为X方向，对应汽车行驶状态下的后方。参阅图13所示，图像产生单元110位于反射偏光器120的Y方向，图像产生单元110朝向反射偏光器120发出入光光束111，入光光束111为图像产生单元110发出并首次和反射偏光器120接触的光束。
本实施方式中，参阅图13和图14所示，图像产生单元110发射的入光光束111呈S线偏振光，图14中呈右上左下方向倾斜的双向箭头表示S线偏振光，S线偏振光可透过第一曲面镜130，透过的入光光束111保持S线偏振光并透过第一偏振转换器140，第一偏振转换器140将入光光束111转变为左旋圆偏振光，图14中逆时针方向弧形箭头表示左旋圆偏振光。本实施方式中第二状态圆偏振光可以为左旋圆偏振光，入光光束111入射到反射偏光器120后被反射偏光器120反射，形成第一折返光束112。
本实施方式中，第一曲面镜130包括第一曲面透反镜132，本实施例以自由曲面透反镜为例，曲面镜具有偏振选择透过性，能够透过第二状态线偏振光，以及反射第一状态线偏振光。并且，第一曲面透反镜132在反射面呈现出自由曲面状，以在反射光束后，能够矫正挡风玻璃的不规则曲面带来的像差。
本实施方式中的第一状态圆偏振光可以为右旋圆偏振光，第二状态圆偏振光可以为左旋圆偏振光，反射偏光器120反射后的第一折返光束112转变为右旋圆偏振光，图14中顺时针方向弧形箭头表示右旋圆偏振光，右旋圆偏振光透过第一偏振转换器140后转变为P线偏振光，图14中呈左上右下方向倾斜的双向箭头表示P线偏振光。呈P线偏振状态的第一折返光束112被第一曲面透反镜132反射，反射后的光束为第二折返光束113。第二折返光束113透过第一偏振转换器140并转变为右旋圆偏振光，本实施方式中的第一状态圆偏振光可以为右旋圆偏振光。第二折返光束113可透过反射偏光器120并射出投影装置100，经过挡风玻璃200反射后在驾驶员的眼睛内成像。
可以理解的是，本实施方式所述的第二状态圆偏振光还可以为左旋圆偏振光，第一状态圆偏振光还可以为右旋圆偏振光，图像产生单元110发出的入光光束111可以呈现P线偏振状态，入光光束111可透过第一曲面透反镜132，并以P线偏振状态透过第一偏振转换器140并转变为右旋圆偏振光。本实施方式中，反射偏光器120可透过左旋圆偏振光，可反射右旋圆偏振光。右旋圆偏振状态的入光光束111被反射偏光器120反射并形成第一折返光束112。
反射偏光器120反射后的第一折返光束112呈左旋圆偏振状态，左旋圆偏振状态的第一折返光束112透过第一偏振转换器140后转变为S线偏振光。S线偏振光被第一曲面透反镜132反射成第二折返光束113，第二折返光束113透过第一偏振转换器140转变为左旋圆偏振 光，左旋圆偏振光可透过反射偏光器120，射出投影装置100，并经过挡风玻璃200反射后在驾驶员的眼睛内成像。
本实施方式中，反射偏光器120可以为具有偏振特性的反射偏光片，可采用两种不同折射率材料组成多层膜，如增亮膜(dual brightness enhancement film，DBEF)，具体可以为反射型偏光增亮膜，由多层组成，例如扩散层、多层反射型偏光片和扩散层等依次层叠形成。具体地，反射偏光片可单独贴合设置于基底层，基底层可以为聚碳酸酯(PC)或玻璃基板。其中，第一偏振转换器140的尺寸，以及反射偏光片和第一偏振转换器140的间距，可根据投影装置100的光学系统架构来设计相对应的参数，以保证光束在不同的口径下全通过，确保第一偏振转换器140的整个尺寸得到有效的利用。并且，反射偏光器120和第一曲面反射镜131的间距设计也根据投影装置100的光学系统架构来设计。
第一偏振转换器140可以为1/4波片(quarter wave plate，QWP)，也可以为1/2波片(half wave plate，HWP)。波片是由晶体制作的平行平面薄片，材料可以是沿平行于水晶或方解石等双折射晶体的光轴而切下的一片晶片，或者为对入射光具有传播方向性的云母片、玻璃纸或聚乙烯醇等材料制成。具体地，波片可以和第一曲面反射镜131的反射表面贴合，或者单独贴合在聚碳酸酯(PC)或玻璃基板上。
一种可能的实施方式中，参阅图15所示，本实施方式所述的投影装置100还包括透镜元件160，透镜元件160位于投影装置100的光束出射端，投影装置100输出的光束透过透镜元件160以发射至投影装置之外。
具体地，透镜元件160可设置在折返光束被反射偏光器120反射或透射的后端光束上。光束经过反射偏光器120、第一曲面镜130和第一偏振转换器140(还可以包含第二偏振转换器150)进行光学系数调整后，通过透镜元件160而出射到挡风玻璃200上。
例如，参阅图15所示，透镜元件160可设置在反射偏光器120和挡风玻璃200之间，并且第一曲面镜130反射的光束可全部透过透镜元件160。
透镜元件160可以对投影装置100出射的光束进行光学调整，提高投影装置100整个架构的光学质量，以降低第一曲面镜130中自由曲面设计加工的难度。并且，在现有的投影装置100生产过程中，各个模块为标准化制备，在面对不同车型等不同的光学需求时，可以通过设计透镜元件的加工参数，就可以满足投影装置100的多个性能，降低投影装置100的整体开发难度和成本。
具体地，透镜元件160可以由树脂、玻璃或微纳结构等材料制成。在形状上，根据投影装置100的光学需求，透镜元件160的外形轮廓可为菲尼尔透镜、透明透镜、非球面透镜或衍射光栅透镜等。
可以理解的是，本实施方式所述的透镜元件160可适用于上述任一实施方式所述的投影装置中。
投影装置100中的光学设计是基于性能指标、材料选用、可测试验收、公差控制、加工装配以及成本等进行确定或优化，这些考虑因素要贯穿产品设计的开始到生成产品的结束，以及在产品应用中的设备调试过程。在整个过程中，特别针对抬头显示装置，自由曲面镜的设计参数对整个产品的成像质量影响较大，而自由曲面镜的参数设计和产品制备对工艺有较高要求。本申请提出在自由曲面实现的同等指标情况下，增加透镜元件160就相当于增加光学设计的优化维度，通过调节透镜元件160的参数设计可优化投影装置的成像，对自由曲面指标的要求降低；同时，改变透镜元件160可满足投影装置的一定性能指标要求，进而可不用改变自由曲面，降低了光学系统优化的难度和复杂度。
一种可能的实施方式中，参阅图16所示，投影装置100还包括匀光元件170(diffuser)，匀光元件170位于所述图像产生单元110的出光侧，图像产生单元110向反射偏光器120发出的光束透过匀光元件170。
匀光元件170可以实现图像产生单元110的投影像面和投影装置100的成像物面，其表面为微纳结构，基底材料为玻璃、树脂或玻璃基底树脂。匀光元件170可以为微列阵结构(MLA)和衍射光学元件(DOE)的独立元件，或着为易于组合菲涅尔元件组合的器件，加工方式可为纳米压印方式、刻蚀方式或注塑成型方式。
匀光元件170是一种实物屏，能够接收图像产生单元110的实像，并对图像进行匀光和光学扩展角控制，为投影装置100中偏振折叠组件提供显示物面。
一种可能的实施方式中，参阅图17所示，投影装置100还包括防眩光膜180，反射偏光器120、第一曲面镜130和第一偏振转换器140形成光路模组，防眩光膜180位于光路模组的出光侧；具体地，参阅图17所示，防眩光膜180可以位于反射偏光器120的上方，并且位于反射偏光器120和透镜元件160之间。光路模组射出的光束透过防眩光膜180后向投影装置100之外发射。
防眩光膜180能够改变光线反射的对称中心，在外界的太阳光透过挡风玻璃200进入到投影装置100内时，太阳光经防眩光膜180反射后的光线偏离驾驶员的眼睛可视范围，例如偏离至驾驶员眼睛的上方，而不会进入到驾驶员的眼睛中，以避免造成驾驶员眩晕不适。
一种可能的实施方式中，参阅图18所示，图18示出了一种投影装置100的结构组成示意图。
投影装置100包含图像产生单元110、反射偏光器120、第一曲面镜130和第一偏振转换器140等装置，或者还包含第二偏振转换器150、透镜元件160、匀光元件170或防眩光膜180等元件。本实施方式中，投影装置100还包含处理器190，处理器190能够生成虚拟图像，并且投影装置100能够发出虚拟图像的光束。
具体地，获取装置获取环境信息，例如，雷达系统获取前方车辆和道路等行驶环境等信息，包含车道信息、前方车距和前方车速等信息，环境信息传递到处理器190中，处理器190队环境信息进行处理。同时，处理器190获取行驶车辆的相关数字信息，例如车速、导航、汽车档位、定速巡航、转速、电量、续航里程与影音娱乐系统等信息，并将所述数字信息和获取的环境信息进行结合，在对应的环境信息处结合相应的数字信息。例如，参阅图5所示，在前车的后侧显示前车距离，在道路路面上显示导航信息的虚拟图像(例如显示左转的提示箭头，并且虚拟箭头和显示的车道相重合)。处理器190在结合环境信息和数字信息后，生成对应虚拟图像的光束，并通过图像产生单元110、反射偏光器120、第一曲面镜130和第一偏振转换器140等装置成像后，经挡风玻璃200反射至驾驶员的眼睛处成像。
一种可能的实施方式中，本实施方式所述的投影装置100中可设置多个曲面镜。参阅图19所示，除了包含第一曲面镜130外，投影装置100还可包含第二曲面镜133，以及还可包含其他曲面镜。本申请所述的反射偏光器和偏振转换器可以设置在图像产生单元110和第一曲面镜130之间。
本申请还提供一种显示设备的具体实施方式，显示设备包括成像屏和上述任一实施方式所述的投影装置，投影装置发出的光束经成像屏折射和/或反射成像。
其中，显示设备可以是投影仪等投影装置，显示屏可以为显示幕布，投影装置100发出的光束直接投影到显示屏上成像。
或者，显示设备还可以是头戴式显示设备，能够投影出虚拟图像至人眼前方，以形成虚 拟的增强显示图像，例如全息眼镜和/或头盔，例如可以应用于增强显示眼镜和增强显示头盔，也可应用于VR眼镜和VR头盔中。其工作原理和汽车的抬头显示原理相类似，不同之处在于光学距离光学参数的设计不同。
本申请还提供一种运载工具的具体实施方式。本申请中的运载工具可以包括路上运载工具、水上运载工具、空中运载工具、工业设备、农业设备、或娱乐设备等。例如运载工具可以为车辆，该车辆为广义概念上的车辆，可以是运载工具(如商用车、乘用车、摩托车、飞行车、火车等)，工业车辆(如：叉车、挂车、牵引车等)，工程车辆(如挖掘机、推土车、吊车等)，农用设备(如割草机、收割机等)，游乐设备，玩具车辆等，本申请实施例对车辆的类型不作具体限定。再如，运载工具可以为飞机、或轮船等运载工具。
其中，运载工具除了诸如发动机或电动机、车轮、方向盘、变速器这样的常用部件之外，车辆还包括上述提到的任意一种投影装置100的实施例，或者包括上述实施方式所述的显示设备。并且，运载工具还包括投影介质，投影介质可以为挡风玻璃200，用于承接投影装置100所发出的光并成像。本实施方式中，投影装置100投射出图像，图像经诸如挡风玻璃200的投影介质折射和/或反射后，最终进入驾驶员的眼睛，使驾驶员透过前挡风玻璃望向车外时，能够在车外看到具有一定景深的虚像。
本申请实施例还提供了一种投影方法，应用于上述任一实施方式所述的投影装置，所述投影装置包括：图像产生单元110、反射偏光器120、第一曲面镜130和第一偏振转换器140，下面对本申请实施例中的投影方法的具体步骤进行详细的描述。
步骤S100、图像产生单元发射偏振光束；具体地，可通过偏振片等偏振机构，实现图像产生单元发射出偏振光束。
步骤S200、偏振光束经由反射偏光器，传播至所述第一偏振转换器，并透过所述第一偏振转换器传播至所述第一曲面镜，经由所述第一曲面镜传播至所述第一偏振转换器，透过所述第一偏振转换器传播至所述反射偏光片，并经由所述反射偏光器，投射出所述投影装置。
图像产生单元发出的偏振光朝向反射偏光器120发射，反射偏光器120的偏振方向和图像产生单元发出偏振光的偏振方向不同，反射偏光器120反射光束，光束在反射偏光器120和第一曲面镜130之间往返传输，第一曲面镜130能够反射偏振光并对圆偏振光的形态进行改变，以及结合第一偏振转换器140对偏振形态的改变，使得往返传输后的光束再次传输到反射偏光器120时能够透射，并最终经过挡风玻璃反射到驾驶员的眼睛成像。
或者，图像产生单元发出的偏振光朝向反射偏光器120发射，反射偏光器120的偏振方向和图像产生单元发出偏振光的偏振方向相同，反射偏光器120透过光束，透过的光束在反射偏光器120和第一曲面镜130之间往返传输，第一曲面镜130能够反射偏振光并对圆偏振光的形态进行改变，以及结合第一偏振转换器140对偏振形态的改变，使得往返传输后的光束再次传输到反射偏光器120时能够被反射，并最终经过挡风玻璃反射到驾驶员的眼睛成像。
本申请还提供一种计算设备。图20是本申请实施例提供的一种计算设备300的结构性示意性图。该计算设备300包括：处理器310、存储器320、通信接口330、总线340。
应理解，图20所示的计算设备300中的通信接口330可以用于与其他设备之间进行通信。
其中，该处理器310可以与存储器320连接。该存储器320可以用于存储该程序代码和数据。因此，该存储器320可以是处理器310内部的存储单元，也可以是与处理器310独立的外部存储单元，还可以是包括处理器310内部的存储单元和与处理器310独立的外部存储单元的部件。
可选的，计算设备300还可以包括总线340。其中，存储器320、通信接口330可以通过 总线340与处理器310连接。总线340可以是外设部件互连标准(Peripheral Component Interconnect，PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，EISA)总线等。所述总线340可以分为地址总线、数据总线、控制总线等。为便于表示，图20中仅用一条线表示，但并不表示仅有一根总线或一种类型的总线。
应理解，在本申请实施例中，该处理器310可以采用中央处理单元(central processing unit，CPU)。该处理器还可以是其它通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field programmable gate Array，FPGA)或者其它可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。或者该处理器310采用一个或多个集成电路，用于执行相关程序，以实现本申请实施例所提供的技术方案。
该存储器320可以包括只读存储器和随机存取存储器，并向处理器310提供指令和数据。处理器310的一部分还可以包括非易失性随机存取存储器。例如，处理器310还可以存储设备类型的信息。
在计算设备300运行时，所述处理器310执行所述存储器320中的计算机执行指令执行上述方法的操作步骤。
应理解，根据本申请实施例的计算设备300可以对应于执行根据本申请各实施例的方法中的相应主体，并且计算设备300中的各个模块的上述和其它操作和/或功能分别为了实现本实施例各方法的相应流程，为了简洁，在此不再赘述。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务 器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
本申请实施例还提供了一种计算机可读存储介质，其上存储有计算机程序，该程序被处理器执行时用于执行一种多样化问题生成方法，该方法包括上述各个实施例所描述的方案中的至少之一。
本申请实施例的计算机存储介质，可以采用一个或多个计算机可读的介质的任意组合。计算机可读介质可以是计算机可读信号介质或者计算机可读存储介质。计算机可读存储介质例如可以是，但不限于，电、磁、光、电磁、红外线、或半导体的系统、装置或器件，或者任意以上的组合。计算机可读存储介质的更具体的例子(非穷举的列表)包括：具有一个或多个导线的电连接、便携式计算机磁盘、硬盘、RAM、ROM、可擦式可编程只读存储器、光纤、便携式紧凑磁盘只读存储器(CD-ROM)、光存储器件、磁存储器件、或者上述的任意合适的组合。在本文件中，计算机可读存储介质可以是任何包含或存储程序的有形介质，该程序可以被指令执行系统、装置或者器件使用或者与其结合使用。
注意，上述仅为本申请的较佳实施例及所运用的技术原理。本领域技术人员会理解，本发明不限于这里所述的特定实施例，对本领域技术人员来说能够进行各种明显的变化、重新调整和替代而不会脱离本发明的保护范围。因此，虽然通过以上实施例对本申请进行了较为详细的说明，但是本发明不仅仅限于以上实施例，在不脱离本发明的构思的情况下，还可以包括更多其他等效实施例，均属于本发明的保护范畴。

Claims (19)

  1. 一种投影装置，其特征在于，包括：图像产生单元、反射偏光器、第一曲面镜和第一偏振转换器，所述图像产生单元用于发射偏振光束；
    所述第一偏振转换器位于所述反射偏光器和所述第一曲面镜之间，用于透过并改变所述偏振光束的偏振态；
    所述第一曲面镜用于处理所述偏振光束；
    所述偏振光束由所述图像产生单元发出后，经由所述反射偏光器，传播至所述第一偏振转换器，并透过所述第一偏振转换器传播至所述第一曲面镜，经由所述第一曲面镜传播至所述第一偏振转换器，透过所述第一偏振转换器传播至所述反射偏光器。
  2. 根据权利要求1所述的投影装置，其特征在于，所述反射偏光器用于透过偏振态为第一状态的偏振光束和反射偏振态为第二状态的偏振光束；
    所述偏振态包括线偏振光和圆偏振光，所述第一状态的偏振光束包括第一状态线偏振光和第一状态圆偏振光，所述第二状态的偏振光束包括第二状态线偏振光和第二状态圆偏振光。
  3. 根据权利要求1或2所述的投影装置，其特征在于，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器靠近所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；
    所述偏振光束经由所述反射偏光器反射，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并透过所述第一偏振转换器传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述偏振光束的偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。
  4. 根据权利要求1-3中任一项所述的投影装置，其特征在于，所述第一偏振转换器包括1/4波片。
  5. 根据权利要求1或2所述的投影装置，其特征在于，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器靠近所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；
    所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并经由所述反射偏光器反射，其偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光并传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述第一曲面反射镜反射的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态圆偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。
  6. 根据权利要求1或2所述的投影装置，其特征在于，所述第一曲面镜包括自由曲面透反镜，所述图像产生单元位于所述自由曲面透反镜背离所述反射偏光器的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；
    所述偏振光束透过所述自由曲面透反镜，透过所述自由曲面透反镜的偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并经由所述反射偏光器反射，其偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光并传播至所述自由曲面透反镜，所述偏振光束经所述自由曲面透反镜反射，所述自由曲面透反镜反射的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态圆偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，并透过所述反射偏光器。
  7. 根据权利要求1或2所述的投影装置，其特征在于，所述第一曲面镜包括第一曲面反射镜，所述图像产生单元位于所述反射偏光器背离所述第一曲面反射镜的一侧，所述图像产生单元发射偏振光束，所述偏振光束的偏振状态为第二状态线偏振光；
    所述偏振光束透过所述反射偏光器，透过所述反射偏光器的偏振光束传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第二状态圆偏振光，并透过所述第一偏振转换器传播至所述第一曲面反射镜，所述偏振光束经所述第一曲面反射镜反射，所述偏振光束的偏振态转换为第一状态圆偏振光，传播至所述第一偏振转换器，所述偏振光束透过所述第一偏振转换器，其偏振态转换为第一状态线偏振光，并透过所述第一偏振转换器传播至所述反射偏光器，偏振光束经所述反射偏光器反射出所述投影装置。
  8. 根据权利要求5或6所述的投影装置，其特征在于，所述投影装置还包括第二偏振转换器，所述第二偏振转换器位于所述反射偏光器远离所述第一曲面反射镜的一侧，所述第二偏振转换器用于将经由所述反射偏振器射出的所述偏振光束由圆偏振光转换为线偏振光。
  9. 根据权利要求8所述的投影装置，其特征在于，所述第二偏振转换器包括1/4波片或1/2波片。
  10. 根据权利要求5-9所述的投影装置，其特征在于，所述第一偏振转换器包括1/4波片或1/2波片。
  11. 根据权利要求1-10中任一项所述的投影装置，其特征在于，所述反射偏光器包括偏光元件，所述偏光元件包括液晶偏振器或反射偏光片中至少一个。
  12. 根据权利要求11所述的投影装置，其特征在于，所述反射偏光器还包括基底层，所述偏光元件贴合设置于所述基底层。
  13. 根据权利要求1-12中任一项所述的投影装置，其特征在于，所述投影装置还包括透镜元件，所述透镜元件位于所述投影装置的光束出射端，所述透镜元件用于调整出射光束的光路。
  14. 根据权利要求1-13中任一项所述的投影装置，其特征在于，所述投影装置还包括匀光元件，所述匀光元件位于所述图像产生单元的出光侧，所述匀光元件用于实现图像产生单元 的投影像面。
  15. 根据权利要求1-14中任一项所述的投影装置，其特征在于，所述投影装置还包括防眩光膜，所述防眩光膜用于处理所述偏振光束，减轻或防止眩光。
  16. 一种显示设备，其特征在于，包括成像屏和上述权利要求1-15中任一项所述的投影装置，所述成像屏用于承接所述投影装置所发出的光并成像。
  17. 根据权利要求16所述的显示设备，其特征在于，所述显示设备包括全息眼镜和/或头盔。
  18. 一种运载工具，其特征在于，包括上述权利要求1-15中任一项所述的投影装置或权利要求16或17所述的显示设备，所述运载工具包括投影介质，所述投影介质用于承接所述投影装置所发出的光并成像。
  19. 一种投影方法，应用于投影装置，所述投影装置包括图像产生单元、反射偏光器、第一曲面镜和第一偏振转换器；所述方法包括：
    所述图像产生单元发射偏振光束，
    所述偏振光束经由所述反射偏光器，传播至所述第一偏振转换器，并透过所述第一偏振转换器传播至所述第一曲面镜，经由所述第一曲面镜传播至所述第一偏振转换器，透过所述第一偏振转换器传播至所述反射偏光片，并经由所述反射偏光器，投射出所述投影装置。
PCT/CN2023/073891 2023-01-30 2023-01-30 投影装置、显示设备、运载工具和投影方法 WO2024159376A1 (zh)

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