Projection device, display device and vehicle

Abstract

The application discloses a projection device, a display device and a vehicle, belongs to the technical field of display, and can be applied to scenarios such as audio-visual entertainment and auxiliary driving, for example, projecting a light beam on an object such as a reflector or a windshield to form an image for a user to watch. The projection device comprises an image light generating unit, a polarization light splitting unit, a projection unit and a light detecting unit; the image light generating unit is used for generating image light; the polarization light splitting unit is used for emitting the image light to the projection unit; the projection unit is used for emitting the image light from the polarization light splitting unit, emitting ambient light to the polarization light splitting unit, and changing the polarization direction of one of the received image light and ambient light, so that the polarization direction of the image light received by the projection unit is different from the polarization direction of the ambient light emitted by the projection unit; the polarization light splitting unit is also used for emitting the ambient light from the projection unit to the light detecting unit; and the light detecting unit is used for detecting the intensity of the ambient light.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a projection device, a display device and a vehicle. BACKGROUND

[0002] The projection device is often used to project image light directly or indirectly onto a target object for a user to watch.

[0003] In the related art, the projection device includes an image light generating unit, a polarization light splitting unit and a projection unit. The image light generating unit is configured to generate image light. The polarization light splitting unit is configured to guide the image light to the projection unit. The projection unit is configured to output the image light.

[0004] If it is necessary to monitor the intensity of ambient light in which the projection device is located, a light detection device needs to be arranged near the projection device to detect the intensity of ambient light in the environment where the projection device is located. The light detection device and the projection device are independently installed, and the devices are relatively scattered, which leads to a relatively complicated installation process. SUMMARY

[0005] The present application provides a projection device, a display device and a vehicle, which can integrate a light detection unit in the interior of the projection device, improve the device integration and facilitate installation.

[0006] In one aspect, the present application provides a projection device. The projection device includes an image light generating unit, a polarization light splitting unit, a projection unit and a light detection unit. The image light generating unit is configured to generate image light, and the image light is linearly polarized light. The polarization light splitting unit is configured to emit the image light from the image light generating unit to the projection unit. The projection unit is configured to emit the image light from the polarization light splitting unit and emit ambient light to the polarization light splitting unit, and the ambient light is linearly polarized light.

[0007] The projection unit is further configured to change the polarization direction of one of the received image light and ambient light, so that the polarization direction of the image light received by the projection unit is different from the polarization direction of the ambient light emitted by the projection unit. That is, the polarization direction of the image light emitted by the polarization light splitting unit is different from the polarization direction of the ambient light incident on the polarization light splitting unit. In this way, the polarization light splitting unit can emit the ambient light from the projection unit to a direction different from the propagation direction of the image light, so as to emit the ambient light from the projection unit to the light detection unit. The light detection unit is configured to detect the intensity of the ambient light from the polarization light splitting unit.

[0008] Since the polarization splitting unit can control the emission of ambient light to the light detection unit integrated inside the projection device based on the polarization direction of the received ambient light, the light detection unit can be integrated inside the projection device, and the device has high integration level and can be installed in place at one time. There is no need to install the light detection unit according to the position of the projection device after the projection device is installed, and the installation is more convenient.

[0009] In the present application, the polarization direction of the image light emitted by the projection unit is the same as the polarization direction of the ambient light received by the projection unit. In this way, the natural light can be polarized by the polarizer to obtain linearly polarized light, and the image light can also pass through the polarizer without affecting the display function of the display device.

[0010] In some examples, the image light generated by the image light generation unit is linearly polarized light with a first polarization direction, and the image light emitted by the projection unit is linearly polarized light with a second polarization direction; the ambient light received by the projection unit and the ambient light emitted by the projection unit are both linearly polarized light with the second polarization direction. That is, the projection unit is used to change the polarization direction of the image light.

[0011] In other examples, the image light generated by the image light generation unit and the image light emitted by the projection unit are both linearly polarized light with a first polarization direction. The ambient light received by the projection unit is linearly polarized light with the first polarization direction, and the ambient light emitted by the projection unit is linearly polarized light with a second polarization direction. That is, the projection unit is used to change the polarization direction of the ambient light.

[0012] Exemplarily, the first polarization direction and the second polarization direction are perpendicular. For example, the linearly polarized light of the first polarization direction is S light, and the light of the second polarization direction is P light. For another example, the linearly polarized light of the first polarization direction is P light, and the light of the second polarization direction is S light.

[0013] In the present application, the projection unit comprises a polarization direction control component and a projection component. The polarization direction control component is used to change the polarization direction of the received image light or ambient light. The projection component is used to emit the image light from the polarization direction control unit and emit the ambient light to the polarization direction control component.

[0014] When the projection unit is used to change the polarization direction of the image light, the polarization direction control component is used to change the polarization direction of the image light from the image light generation unit from a first polarization direction to a second polarization direction, emit the image light with the second polarization direction to the projection component, and emit the ambient light from the projection component to the light detection unit without changing the polarization direction, the polarization direction of the ambient light being the second polarization direction.

[0015] When the projection unit is used to change the polarization direction of the ambient light, the polarization direction control component is configured to emit the image light from the image light generation unit to the projection component without changing the polarization direction of the image light, change the polarization direction of the ambient light from the projection component from a first polarization direction to a second polarization direction, and emit the ambient light of the second polarization direction to the light detection unit, the polarization direction of the image light being the first polarization direction.

[0016] Exemplarily, the polarization direction control component comprises a half-wave plate and an optical rotator, which are sequentially located on the light path between the polarization beam splitter and the projection component. The half-wave plate is configured to rotate the polarization direction of the first light beam by 45 degrees in a first direction and rotate the polarization direction of the second light beam by 45 degrees in a second direction. The optical rotator is configured to rotate the polarization direction of the first light beam by 45 degrees in the first direction and rotate the polarization direction of the second light beam by 45 degrees in the first direction. After the first light beam passes through the half-wave plate and the optical rotator, the polarization direction of the first light beam is rotated by 90 degrees in the first direction, while the polarization direction of the second light beam remains unchanged after the second light beam passes through the half-wave plate and the optical rotator. Therefore, the first light beam is the light of the image light and the ambient light whose polarization direction is changed after passing through the projection unit, and the second light beam is the light of the image light and the ambient light whose polarization direction is not changed after passing through the projection unit.

[0017] Wherein, the first direction and the second direction are opposite, for example, the first direction is clockwise and the second direction is counterclockwise. Alternatively, the first direction is counterclockwise and the second direction is clockwise.

[0018] In some examples, the projection component comprises a lens. In this case, the ambient light needs to be changed into linearly polarized light by an external device before being incident on the projection device through the lens.

[0019] In other examples, the projection component comprises a lens and a polarizer, which are sequentially located on the exit light path of the image light from the polarization direction control component. The polarization direction of the polarizer is the same as the polarization direction of the image light emitted by the projection unit. The polarizer can change the external ambient light into linearly polarized light before being incident on the projection device through the lens.

[0020] Optionally, the polarizer can be directly attached to the surface of the lens, or the polarizer can be arranged in a spaced manner with the lens.

[0021] In a possible implementation, the image light generating unit includes an illumination light source and a light modulation device. The illumination light source is configured to provide a third light beam. The light modulation device is configured to perform light modulation on at least part of the third light beam to obtain the image light. The polarization beam splitting unit has a splitting surface, and the light detection unit and the light modulation device are located on two sides of the splitting surface respectively.

[0022] Optionally, the light modulation device includes a reflective spatial light modulation device or a transmissive spatial light modulation device.

[0023] In some examples, the illumination light source and the reflective spatial light modulation device are located on one side of the splitting surface, and the light detection unit is located on the other side of the splitting surface. In other examples, the illumination light source and the light detection unit are located on one side of the splitting surface, and the reflective spatial light modulation device is located on the other side of the splitting surface. The polarization beam splitting unit is configured to emit a fourth light beam from the third light beam to the light modulation device, the fourth light beam being at least part of the third light beam. The light modulation device is configured to perform light modulation on the fourth light beam to obtain the image light. In this way, the devices in the polarization beam splitting unit can be multiplexed as the devices in the image light generating unit, so that the number of devices in the projection device is reduced, and the volume of the projection device is reduced.

[0024] When the fourth light beam and the third light beam are linearly polarized light and have the same polarization direction, the polarization beam splitting unit guides the third light beam to the light modulation device. For example, when the fourth light beam and the third light beam are both S light, the polarization beam splitting unit reflects the third light beam to the light modulation device. For another example, when the fourth light beam and the third light beam are both P light, the polarization beam splitting unit transmits the third light beam to the light modulation device. In this case, the light beam output by the illumination light source is substantially not incident on the light detection unit. The light detection unit includes a first light detection device configured to detect the intensity of the ambient light from the polarization beam splitting unit.

[0025] When the third light beam is circularly or elliptically polarized light, the polarization beam splitting unit divides the third light beam into a fourth light beam and a fifth light beam, emits the fourth light beam to the light modulation device, and emits the fifth light beam to the light detection unit. For example, the fourth light beam is S light, and the fifth light beam is P light, so that the polarization beam splitting unit reflects the S light component in the third light beam to the light modulation device as the fourth light beam, and transmits the P light component in the third light beam to the light detection unit as the fifth light beam. For another example, the fourth light beam is P light, and the fifth light beam is S light, so that the polarization beam splitting unit transmits the P light component in the third light beam to the light modulation device as the fourth light beam, and reflects the S light component in the third light beam to the light detection unit as the fifth light beam.

[0026] In this case, the fifth light beam and the ambient light are both emitted to the light detection unit, and the fifth light beam affects the detection result of the first light detection device used to detect the intensity of the ambient light. Therefore, the light detection unit comprises a filter and the first light detection device. The filter is used to emit the fifth light beam from the polarization beam splitting unit to a position outside the first light detection device, and emit light in a target wavelength range from the ambient light from the polarization beam splitting unit to the first light detection device, the target wavelength range being non-overlapping with the wavelength of the fifth light beam. The first light detection device is used to detect the intensity of the ambient light from the polarization beam splitting unit. The light beam output by the illumination light source can be avoided from being received by the first light detection device through the filter.

[0027] Optionally, in some examples, the light detection unit can detect the intensity of the third light beam output by the illumination light source in addition to detecting the intensity of the ambient light. Here, the light detection unit further comprises a second light detection device. The filter is used to emit the fifth light beam from the polarization beam splitting unit to the second light detection device. The second light detection device is used to detect the intensity of the fifth light beam from the polarization beam splitting unit.

[0028] In some examples, the reflective spatial light modulator has the function of changing the polarization direction of the incident linearly polarized light, for example, the reflective spatial light modulator is a liquid crystal on silicon (LCoS).

[0029] In other examples, the reflective spatial light modulator does not have the function of changing the polarization direction of the incident linearly polarized light, for example, the reflective spatial light modulator is a micro-electro-mechanical system (MEMS) modulator or a digital micromirror device (DMD) modulator. In this case, the light modulation device further comprises a 1 / 4 wave plate located on the optical path between the reflective spatial light modulator and the polarization beam splitting unit, used to change the polarization direction of the image light.

[0030] In some examples, the light detection unit is only used to detect the intensity of the ambient light. In this case, the polarization beam splitting unit is also used to guide the third light beam to the light modulation device; the light detection unit comprises a first light detection device, and the first light detection device is used to detect the intensity of the ambient light from the polarization beam splitting unit.

[0031] In some examples, the light detection unit is configured to detect intensity of the ambient light. The polarization beam splitting unit is further configured to split the third light beam into a fourth light beam and a fifth light beam, to emit the fourth light beam towards the light modulator, and to emit the fifth light beam towards the light detection unit. The light modulator is configured to perform light modulation on the fourth light beam to obtain the image light. The light detection unit is further configured to detect intensity of the fifth light beam from the polarization beam splitting unit.

[0032] In some examples, the light detection unit includes a filter, a first light detection device and a second light detection device. The filter is configured to emit the portion of the ambient light from the polarization beam splitting unit towards the first light detection device, and to emit the fifth light beam from the polarization beam splitting unit towards the second light detection device. The first light detection device is configured to detect intensity of the ambient light from the polarization beam splitting unit. The second light detection device is configured to detect intensity of the fifth light beam from the polarization beam splitting unit.

[0033] When the light modulation device includes a transmissive spatial light modulator, the illumination light source and the transmissive spatial light modulator are located on the same side of the polarization beam splitting unit. The transmissive spatial light modulator can be a liquid crystal modulator. Compared with a reflective spatial light modulator, a transmissive spatial light modulator has higher light utilization efficiency, which is beneficial to energy saving.

[0034] In another possible implementation, the image light generation unit includes a direct imaging type image source, such as an organic light-emitting diode (OLED) display, a liquid crystal display (LCD), a micro light-emitting diode (micro-LED) display, a mini LED display, etc.

[0035] In some examples, the polarization beam splitting unit includes a polarization beam splitter (PBS).

[0036] In another aspect, the present application provides a display device. The display device includes a main processor and a projection apparatus, the projection apparatus being any one of the aforementioned projection apparatuses, and the main processor being configured to send image data to the projection apparatus.

[0037] In some examples, the display device further includes a power supply configured to supply power to the main processor and the projection apparatus.

[0038] Optionally, the display device further comprises a reflecting device for reflecting the image light projected by the projection device to form an image.

[0039] In some examples, the display device is a projector and the reflecting device is a light screen. In other examples, the display device is an augmented reality (AR) glasses. In yet other examples, the display device is a car lamp or the like.

[0040] In yet other examples, the display device is a head-up display device. The projection device is configured to project the image light to a windshield to form an image.

[0041] In yet another aspect, the present application provides a vehicle comprising any of the aforementioned display devices. Exemplarily, the vehicle includes but is not limited to a car, an airplane, a train, a ship or the like. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a structural schematic diagram of a projection device provided by an embodiment of the present application;

[0043] Figure 2 is a structural schematic diagram of another projection device provided by an embodiment of the present application;

[0044] Figure 3 is a structural schematic diagram of yet another projection device provided by an embodiment of the present application;

[0045] Figure 4 is a structural schematic diagram of yet another projection device provided by an embodiment of the present application;

[0046] Figure 5 is a structural schematic diagram of yet another projection device provided by an embodiment of the present application;

[0047] Figure 6 is a structural schematic diagram of a display device provided by an embodiment of the present application;

[0048] Figure 7 is a structural schematic diagram of another display device provided by an embodiment of the present application;

[0049] Figure 8 is a circuit schematic diagram of a display device provided by an embodiment of the present application;

[0050] Figure 9 is a functional framework schematic diagram of a vehicle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0051] The projection device provided by an embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0052] The projection device provided in the embodiments of the present application can be used alone or integrated as a component in a display device, including but not limited to a projector, a head-up display device, and a vehicle lamp, etc. That is, the projection device can be applied to scenarios such as audio-visual entertainment and auxiliary driving. Exemplarily, the projection device is a picture generation unit (PGU) of a head-up display device, and the PGU is also referred to as an optical engine.

[0053] Figure 1 FIG. 1 is a structural schematic diagram of a projection device provided in the embodiments of the present application. As shown in the figure, the projection device includes an image light generation unit 110, a polarization light splitting unit 120, a projection unit 130, and a light detection unit 140. Figure 1 The image light generation unit 110 is configured to generate image light, and the image light is linearly polarized light. The polarization light splitting unit 120 is configured to emit the image light from the image light generation unit 110 towards the projection unit 130. The projection unit 130 is configured to emit the image light from the polarization light splitting unit 120, and emit ambient light towards the polarization light splitting unit 120, and the ambient light is linearly polarized light.

[0054] The projection unit 130 is further configured to change the polarization direction of one of the received image light and the ambient light, so that the polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130. The polarization light splitting unit 120 is further configured to emit the ambient light from the projection unit 130 towards the light detection unit 140. The light detection unit 140 is configured to detect the intensity of the ambient light from the polarization light splitting unit.

[0055] In the embodiments of the present application, the polarization light splitting unit 120 controls the light splitting and the propagation direction of the light beam based on the polarization state of the light. The image light received by the projection unit 130 is the image light emitted by the polarization light splitting unit 120, and the ambient light emitted by the projection unit 130 is the ambient light incident on the polarization light splitting unit 120. The polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130, that is, the polarization direction of the image light emitted by the polarization light splitting unit 120 is different from the polarization direction of the ambient light incident on the polarization light splitting unit 120. In this way, the polarization light splitting unit 120 can propagate the ambient light in a direction different from the incident direction of the image light, so that the light detection unit integrated inside the projection device can receive the ambient light and detect the received ambient light. By integrating the light detection unit inside the projection device, the device integration degree is high, and the light detection unit can be installed in place at one time. There is no need to install the light detection unit according to the position of the projection device after the projection device is installed, and the installation is more convenient.

[0056] In the embodiments of the present application, the projection unit 130 changes the polarization direction of one of the received image light and the ambient light, which refers to any one of the following two cases:

[0057] Firstly, the projection unit 130 is configured to change the polarization direction of the received image light, so that the polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the image light emitted by the projection unit 130, for example, perpendicular. At the same time, the projection unit 130 does not change the polarization direction of the received ambient light, so that the polarization direction of the ambient light received by the projection unit 130 is the same as the polarization direction of the ambient light emitted by the projection unit 130.

[0058] Secondly, the projection unit 130 is configured to change the polarization direction of the received ambient light, so that the polarization direction of the ambient light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130, for example, perpendicular. At the same time, the projection unit 130 does not change the polarization direction of the received image light, so that the polarization direction of the image light received by the projection unit 130 is the same as the polarization direction of the image light emitted by the projection unit 130.

[0059] In the embodiments of the present application, the polarization direction of the image light emitted by the projection unit 130 is the same as the polarization direction of the ambient light received by the projection unit 130. In this way, the natural light can be polarized by the polarizer to obtain linearly polarized light, and at the same time, the image light can also pass through the polarizer without affecting the display function of the display device.

[0060] Figure 1 In the embodiments of the present application, the above-mentioned second case is taken as an example for illustration. In this case, the image light received by the projection unit 130 and the image light emitted by the projection unit 130 are both P light, the ambient light received by the projection unit 130 is P light, and the ambient light emitted by the projection unit 130 is S light. Alternatively, the image light received by the projection unit 130 and the ambient light emitted by the projection unit 130 can also be S light, and the ambient light received by the projection unit 130 is S light, and the ambient light emitted by the projection unit 130 is P light.

[0061] In the embodiments of the present application, the image light generating unit 110 can adopt a direct imaging type image source, such as an OLED display, an LCD, a micro-LED display, a mini LED display, and the like. Alternatively, the image light generating unit 110 can adopt a projection type image source, for example, the image light generating unit 110 can include an illumination light source and a light modulation device. The illumination light source is configured to provide a third light beam. The light modulation device is configured to perform light modulation on at least part of the third light beam to obtain image light. The polarization beam splitting unit has a splitting surface, and the light detection unit and the light modulation device are located on two sides of the splitting surface, respectively. Optionally, the light modulation device can include a reflective spatial light modulator or a transmissive spatial light modulator.

[0062] Exemplarily, the polarization beam splitting unit 120 can include a PBS. The PBS can transmit P light in the incident light beam and reflect S light in the incident light beam. The PBS includes two right-angle prisms with opposite hypotenuses and a medium layer sandwiched between the two right-angle prisms. The medium layer can be prepared by a coating process.

[0063] The light detection unit 140 includes a first light detection device, such as a photomultiplier tube, a photo-diode (PD), or an avalanche photo-diode, for detecting the intensity of the received ambient light.

[0064] Figure 2 is a structural schematic diagram of another projection device provided by an embodiment of the present application. As shown in Figure 2 the projection device includes an image light generation unit 110, a polarization beam splitting unit 120, a projection unit 130, and a light detection unit 140. The image light generation unit 110 is configured to generate image light, which is linearly polarized light. The polarization beam splitting unit 120 is configured to emit the image light from the image light generation unit 110 towards the projection unit 130. The projection unit 130 is configured to emit the image light from the polarization beam splitting unit 120 and emit ambient light towards the polarization beam splitting unit 120, the ambient light being linearly polarized light. The projection unit 130 is further configured to change the polarization direction of the image light, so that the polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130. The polarization beam splitting unit 120 is further configured to emit the ambient light from the projection unit 130 towards the light detection unit 140. The light detection unit 140 is configured to detect the intensity of the ambient light from the polarization beam splitting unit.

[0065] As shown in Figure 2 the projection unit 130 includes a polarization direction control component 131 and a projection component 132. The polarization direction control component 131 is configured to change the polarization direction of the image light from the image light generation unit 110 from a first polarization direction to a second polarization direction, emit the image light with the second polarization direction towards the projection component 132, and emit the ambient light from the projection component 132 towards the light detection unit 140 without changing the polarization direction. Here, the polarization direction of the ambient light is the second polarization direction.

[0066] The first polarization direction is perpendicular to the second polarization direction. In Figure 2 the first polarization direction is P light, and the second polarization direction is S light.

[0067] Exemplarily, the polarization direction control assembly 131 comprises a half-wave plate 1311 and an optical rotator 1312, which are sequentially arranged on the light path between the polarization splitting unit 120 and the projection assembly 132. The half-wave plate 1311 and the optical rotator 1312 can be arranged in sequence along the exiting direction of the image light or arranged in sequence along the direction opposite to the exiting direction of the image light, which is not limited in the present application.

[0068] The half-wave plate 1311 is configured to rotate the polarization direction of the image light by 45 degrees along a first direction, and the optical rotator 1312 is configured to rotate the polarization direction of the image light by 45 degrees along the first direction. In this way, the polarization direction control assembly 131 rotates the polarization direction of the image light by 90 degrees along the first direction, so as to change the image light from P light to S light after exiting.

[0069] The half-wave plate 1311 is also configured to rotate the polarization direction of the ambient light by 45 degrees along a second direction, and the optical rotator 1312 is also configured to rotate the polarization direction of the ambient light by 45 degrees along the first direction. The first direction and the second direction are opposite. For example, the first direction is the clockwise direction, and the second direction is the counterclockwise direction. Alternatively, the first direction is the counterclockwise direction, and the second direction is the clockwise direction. In this way, the polarization direction control assembly 131 does not change the polarization direction of the ambient light passing through itself. The polarization direction of the ambient light exiting the polarization direction control assembly 131 is still S light.

[0070] In the embodiments of the present application, the optical rotator 1312 can be a magneto-optical crystal, such as a Faraday rotator, etc. The magneto-optical crystal can rotate the polarization plane of the light incident in the forward direction and the light incident in the reverse direction by the same angle in the same direction, i.e., the rotation direction of the polarization plane is independent of the propagation direction of the light beam. However, the rotation direction of the polarization plane of the light by the half-wave plate 1311 is related to the propagation direction of the light beam.

[0071] In some examples, the projection assembly 132 comprises a lens 1321. In this case, it is necessary to change the ambient light into linearly polarized light by an external device before the ambient light is incident into the projection device through the lens.

[0072] In other examples, in addition to the lens 1321, the projection assembly 132 can further comprise a polaroid (not shown in the figure), and the lens and the polaroid are sequentially arranged on the exiting light path of the image light from the polarization direction control assembly 131. The polarization direction of the polaroid is the same as the polarization direction of the image light exiting the projection unit. The polaroid can change the external ambient light into linearly polarized light before the ambient light is incident into the projection device through the lens.

[0073] Optionally, the polaroid can be directly attached to the surface of the lens 1321, or the polaroid can be arranged in a spaced manner with the lens 1321.

[0074] In the embodiments of the present application, the lens includes a lens barrel and a lens group located in the lens barrel. The lens group includes one or more optical lenses. The embodiments of the present application do not limit the structure of the lens group, and the lens group can be set according to actual needs.

[0075] As shown in Figure 2 , the image light generation unit 110 includes an illumination light source 111 and a light modulation device 112. The illumination light source 111 is configured to provide a third light beam (i.e., backlight in Figure 2 ). The light modulation device 112 is configured to perform light modulation on at least part of the third light beam to obtain image light. The polarization light splitting unit 120 has a light splitting surface 121, and the light detection unit 140 and the light modulation device 112 are located on two sides of the light splitting surface 121, respectively. The polarization light splitting unit 120 is also configured to guide at least part of the third light beam to the light modulation device 112.

[0076] Exemplarily, in Figure 2 , the third light beam provided by the illumination light source 111 is S light, and the polarization light splitting unit 120 is configured to reflect the third light beam to the light modulation device 110. The light modulation device 112 is configured to perform light modulation on the third light beam and change the polarization direction of the third light beam to obtain image light. The polarization direction of the image light is perpendicular to the polarization direction of the third light beam, which is P light.

[0077] In some examples, the light modulation device 112 includes a reflective spatial light modulator having a function of changing the polarization direction of the incident linearly polarized light, such as LCoS. In some examples, the LCoS can include an array substrate, a glass cover plate, and liquid crystals arranged between the two. The array substrate includes a control circuit array layer and a reflection layer. The control circuit array layer is configured to control the deflection of the liquid crystals to change the polarization direction of the received linearly polarized light, and the reflection layer is capable of reflecting the received linearly polarized light to change the propagation direction of the linearly polarized light.

[0078] In other examples, the light modulation device 112 includes a reflective spatial light modulator (such as a MEMS modulator or a DMD modulator) without the function of changing the polarization direction of the incident linearly polarized light and a 1 / 4 wave plate. The 1 / 4 wave plate is located on the optical path between the reflective spatial light modulator and the polarization light splitting unit, and is configured to change the polarization direction of the image light.

[0079] The light detection unit 140 includes a first light detection device 141 configured to detect the intensity of the received ambient light.

[0080] The first light detection device and the related content of the polarization light splitting unit are described in Figure 1 .

[0081] Figure 3 is a structural schematic diagram of another projection device provided by the embodiments of the present application.Figure 3 The projection device shown in Figure 2 The difference between the projection device shown in

[0082] As shown in Figure 3 The third light beam output by the illumination unit 110 is circularly polarized light or elliptically polarized light. The polarization beam-splitting unit 120 is used to split the third light beam into a fourth light beam and a fifth light beam, guide the fourth light beam to the light modulation device 112, and guide the fifth light beam to the light detection unit 140. The fourth light beam is S light, and the polarization beam-splitting unit 120 reflects the fourth light beam to the light modulation device 112. The fifth light beam is P light, and the polarization beam-splitting unit 120 transmits the fifth light beam to the light detection unit 140.

[0083] The light detection unit 140 includes a first light detection device 141, a filter 142, and a second light detection device 143. The filter 142 is used to emit the fifth light beam from the polarization beam-splitting unit 120 to the second light detection device 143, and the second light detection device 142 is used to detect the intensity of the fifth light beam from the polarization beam-splitting unit. The filter 142 is also used to emit light in a target wavelength range from the ambient light from the polarization beam-splitting unit 120 to the first light detection device 141, and the target wavelength range is non-overlapping with the wavelength of the fifth light beam. The first light detection device 141 is used to detect the intensity of the ambient light from the polarization beam-splitting unit.

[0084] Exemplarily, the filter 142 is a band-pass filter, that is, the light in the wavelength range corresponding to the fifth light beam is transmitted to the second light detection device 143, and the light in the target wavelength range is reflected to the first light detection device 141.

[0085] It should be noted that when the brightness of the backlight does not need to be detected, the second light detection device 143 in Figure 3 may be removed, as long as the filter 142 can emit the fifth light beam from the polarization beam-splitting unit 120 to a position outside the first light detection device, that is, the brightness of the backlight can be avoided to affect the detection result of the first light detection device 141.

[0086] In this embodiment, the light detection unit 140 can detect the intensity of the ambient light and the brightness of the backlight. In this way, the brightness of the backlight can be adjusted in combination with the brightness of the ambient light to improve the comfort of the human eye and improve the user experience. Moreover, the ambient light and the backlight are separated by the filter 142, so that the propagation paths of the ambient light and the backlight can partially overlap, the devices in the projection device can be reused to control the propagation paths of the ambient light and the backlight, which is beneficial to reduce the volume of the projection device.

[0087] Figure 4Fig. 1 is a structural schematic diagram of a projection device provided by an embodiment of the present application. Figure 4 The projection device shown in Fig. 1 is different from the projection device shown in Fig. 2 in that the projection unit 130 is configured to change the polarization direction of the ambient light, so that the polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130. Figure 3 The projection device shown in Fig. 1 is different from the projection device shown in Fig. 2 in that the projection unit 130 is configured to change the polarization direction of the ambient light, so that the polarization direction of the image light received by the projection unit 130 is different from the polarization direction of the ambient light emitted by the projection unit 130.

[0088] When the projection unit 130 is configured to change the polarization direction of the ambient light, the polarization direction control component 131 is configured to emit the received image light to the projection component 132 without changing the polarization direction of the image light, change the polarization direction of the ambient light from the first polarization direction to the second polarization direction from the projection component 132, and emit the ambient light of the second polarization direction to the light detection unit 140, the polarization direction of the image light being the first polarization direction.

[0089] In the projection device shown in Fig. 1, the linearly polarized light of the first polarization direction is S light, and the linearly polarized light of the second polarization direction is P light. Figure 4 Exemplarily, the polarization direction control component 131 includes a half-wave plate 1311 and an optical rotator 1312, and the half-wave plate 1311 and the optical rotator 1312 are sequentially located on the light path between the polarization light splitting unit 120 and the projection component 132. The half-wave plate 1311 and the optical rotator 1312 can be sequentially arranged along the emission direction of the image light or sequentially arranged along the direction opposite to the emission direction of the image light, and the present application does not limit this.

[0090] The half-wave plate 1311 is configured to rotate the polarization direction of the ambient light by 45 degrees along a first direction, and the optical rotator 1312 is configured to rotate the polarization direction of the ambient light by 45 degrees along the first direction. In this way, the polarization direction control component 131 rotates the polarization direction of the ambient light by 90 degrees along the first direction, so as to change the ambient light from S light to P light and then emit the ambient light to the polarization light splitting unit 120.

[0091] The half-wave plate 1311 is further configured to rotate the polarization direction of the image light by 45 degrees along a second direction, and the optical rotator 1312 is further configured to rotate the polarization direction of the image light by 45 degrees along the first direction. The first direction and the second direction are opposite to each other. For example, the first direction is a clockwise direction, and the second direction is a counterclockwise direction. Alternatively, the first direction is a counterclockwise direction, and the second direction is a clockwise direction. In this way, the polarization direction control component 131 does not change the polarization direction of the image light passing through itself. The polarization direction of the image light emitted by the polarization direction control component 131 is still S light.

[0092] Exemplarily, the projection device shown in Fig. 1 further includes a polarization direction control component 131, the polarization direction control component 131 is configured to change the polarization direction of the ambient light, and the polarization direction control component 131 is located between the projection component 132 and the light detection unit 140.

[0093] Figure 4 ​In the projection unit 112, the third beam output from the illumination source 111 is a P-beam. The polarization beam splitter 120 transmits this third beam to the light modulator 112. The light modulator 112 modulates the third beam, changing its polarization direction to obtain image light, and reflects this image light back to the polarization beam splitter 120. This image light is an S-beam. The polarization beam splitter 120 then reflects the image light to the projection unit 130.

[0094] Figure 5 This is a schematic diagram of the structure of another projection device provided in the embodiments of this application. Figure 5 The projection device shown is Figure 4 The difference between the projection devices shown lies in the polarization state of the third beam output by the illumination unit 110 and the structure of the light detection unit 140.

[0095] like Figure 5 As shown, the third beam output by the illumination unit 110 is either circularly polarized or elliptically polarized light. The polarization beam splitting unit 120 is used to split the third beam into a fourth beam and a fifth beam, guide the fourth beam to the light modulator 112, and guide the fifth beam to the light detection unit 140. The fourth beam is P-beam, which is transmitted by the polarization beam splitting unit 120 to the light modulator 112; the fifth beam is S-beam, which is reflected by the polarization beam splitting unit 120 to the light detection unit 140.

[0096] For details regarding the optical detection unit 140, please refer to [link / reference]. Figure 3 The illustrated embodiment is omitted in detail here.

[0097] In this embodiment, the illumination source 111 may include a combination of a light-emitting device and various optical mirrors. The optical device may be an LED or a laser, etc., and the optical mirrors may include prisms and collimating lenses, etc. This embodiment does not limit the structure of the illumination source 111, as long as it can provide a third beam with a corresponding polarization state.

[0098] It should be noted that, in Figures 2 to 5 In the embodiments shown, a reflective spatial light modulator is used as an example. In other embodiments, a transmissive spatial light modulator, such as a liquid crystal modulator, can also be used. In this case, the transmissive light modulator is located in the optical path between the illumination source and the polarization beam splitter.

[0099] This application also provides a display device, which includes a main processor and a projection device, wherein the projection device is any of the aforementioned projection devices. The main processor is used to send image data to the projection device.

[0100] Optionally, the display device further comprises a reflecting device, and the projecting apparatus is configured to project the image light on the reflecting device, and the reflecting device is configured to reflect the image light projected by the projecting apparatus to form a corresponding image.

[0101] Optionally, the display device further comprises a power supply configured to supply power to the main processor and the projecting apparatus.

[0102] In some examples, as shown in FIG. 1, the display device is a projector 100a, and the reflecting device is a light screen, such as a projection screen 1. In other examples, the display device is an AR glass. In yet other examples, the display device is a car lamp or the like. Figure 6

[0103] In some examples, the projecting apparatus 71 in the display device is configured to project the image light on the windshield 2 to form an image S1. Exemplarily, as shown in FIG. 2, the display device is a HUD 100b. Figure 7

[0104] Exemplarily, the windshield 2 is a windshield of a vehicle. The vehicle includes, but is not limited to, a car, an airplane, a train, or a ship, etc.

[0105] In some examples, the image is an augmented reality display image configured to display information, such as indication information of an external object, navigation information, etc. The indication information of the external object includes, but is not limited to, a safe distance, surrounding obstacles, and a reversing image, etc. The navigation information includes, but is not limited to, a direction arrow, a distance, and a travel time, etc.

[0106] In other examples, the image is a status display image configured to display status information of the vehicle. Taking a car as an example, the status information of the vehicle includes, but is not limited to, a travel speed, a travel mileage, a fuel level, a water temperature, and a car lamp status, etc.

[0107] In yet other examples, the image includes the augmented reality display image and the status display image.

[0108] Optionally, in order to project the image light output by the projecting apparatus to a proper position on the windshield, the HUD further comprises a spatial light path structure configured to guide the image light to the windshield. The spatial light path structure includes one or more of the following optical devices: a lens, a plane mirror, a curved mirror, etc.

[0109] Exemplarily, as shown in FIG. 3, the spatial light path structure includes a lens 3. Figure 7 ​​As shown, the spatial light path structure includes a first mirror 72a and a second mirror 72b. The image light emitted by the projection device passes through the first mirror 72a and the second mirror 72b in sequence and then reaches the windshield 2. The ambient light passes through the second mirror 72b and the first mirror 72a in sequence and then is emitted to the projection device 71. The second mirror 72b is a concave mirror, and the first mirror 72a is a convex mirror or a plane mirror.

[0110] After passing through the second mirror 72b and the first mirror 72a, the ambient light is energy-concentrated, so that the energy of the ambient light incident into the projection device 71 is strong, thereby the sensitivity requirement of the first light detection device can be reduced.

[0111] Optionally, the spatial light path structure can further include more mirrors, such as the third mirror 72c in the figure, for changing the propagation direction of the image light as needed.

[0112] Optionally, in order to improve the imaging quality, the HUD can further include a diffusion screen 73, which is located on the light path between the projection device 71 and the spatial light path structure.

[0113] Optionally, the HUD can further include a dust cover 74. The dust cover 74 is located below the windshield 2 and is used to protect the projection device 71 and the spatial light path structure and the like. In some examples, the dust cover 74 is integrated with the function of a polaroid. The polarization direction of the polaroid is the same as the polarization direction of the image light.

[0114] The embodiments of the present application also provide a vehicle, which includes any one of the aforementioned HUDs and a windshield, the windshield being configured to reflect the image light from the HUD to an eyebox to form a corresponding image, wherein the eyebox is an area where the driver's two eyes are located.

[0115] Figure 8 is a circuit schematic diagram of a display device provided by the embodiments of the present application. As shown, Figure 8 the circuit in the display device mainly includes a host CPU 801, an external memory interface 802, an internal memory 803, an audio module 804, a video module 805, a power module 806, a wireless communication module 807, an I / O interface 808, a video interface 809, a display circuit 810, and a light modulation device 112, etc. The host CPU 801 and its peripheral elements, such as the external memory interface 802, the internal memory 803, the audio module 804, the video module 805, the power module 806, the wireless communication module 807, the I / O interface 808, the video interface 809, and the display circuit 810 can be connected through a bus. The host CPU 801 can be referred to as a front-end processor.

[0116] In addition, the circuit diagram schematically shown in the embodiments of the present application does not constitute a specific limitation on the display device. In some other embodiments of the present application, the display device can include more or fewer components than those shown, or combine some components, or split some components, or different arrangement of components. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0117] The main processor 801 includes one or more processing units. For example, the main processor 801 can include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units can be independent devices or integrated into one or more processors.

[0118] The main processor 801 can also be provided with a memory for storing instructions and data. In some embodiments, the memory in the main processor 801 is a cache memory. The memory can store instructions or data that have just been used or recycled by the main processor 801. If the main processor 801 needs to use the instructions or data again, it can directly call them from the memory. This avoids repeated access and reduces the waiting time of the main processor 801, thereby improving the efficiency of the system.

[0119] In some embodiments, the display device can further include a plurality of input / output (I / O) interfaces 808 connected to the main processor 801. The interfaces 808 can include an Inter-Integrated Circuit (I2C) interface, an Inter-Integrated Circuit Sound (I2S) interface, a Pulse Code Modulation (PCM) interface, a Universal Asynchronous Receiver / Transmitter (UART) interface, a Mobile Industry Processor Interface (MIPI), a General-Purpose Input / Output (GPIO) interface, a Subscriber Identity Module (SIM) interface, and / or a Universal Serial Bus (USB) interface, etc. The I / O interfaces 808 described above can be connected to devices such as a mouse, a touchpad, a keyboard, a camera, a speaker / loudspeaker, a microphone, etc., and can also be connected to physical keys (such as a volume key, a brightness adjustment key, a power on / off key, etc.) on the display device.

[0120] The external memory interface 802 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the display device. The external memory card communicates with the main processor 801 through the external memory interface 802 to implement data storage functions.

[0121] The internal memory 803 can be used to store computer executable program codes, which include instructions. The internal memory 803 can include a program storage area and a data storage area. The program storage area can store an operating system, at least one application program required by a function (such as a call function, a time setting function, etc.), etc. The data storage area can store data created during use of the display device (such as a phone book, a world time, etc.), etc. In addition, the internal memory 803 can include a high-speed random access memory, and can also include a non-volatile memory such as at least one magnetic disk storage device, a flash memory device, a Universal Flash Storage (UFS), etc. The main processor 801 executes various function applications and data processing of the display device by running instructions stored in the internal memory 803 and / or instructions stored in a memory disposed in the main processor 801.

[0122] The display device can realize audio functions through the audio module 804 and the application processor, etc. For example, music playing, calling, etc.

[0123] The audio module 804 is configured to convert digital audio information into an analog audio signal output, and is also configured to convert an analog audio input into a digital audio signal. The audio module 804 can also be configured to encode and decode audio signals, such as playing or recording. In some embodiments, the audio module 804 can be disposed in the processor 101, or part of the functions of the audio module 804 can be disposed in the processor 101.

[0124] The video interface 809 can receive external input audio and video signals, which can be a high-definition multimedia interface (HDMI), a digital video interface (DVI), a video graphics array (VGA), a display port (DP), etc. The video interface 809 can also output video externally. When the display device is used as a head-up display, the video interface 809 can receive speed signals and power signals input by peripheral devices, and can also receive external input AR video signals. When the display device is used as a projector, the video interface 809 can receive video signals input by external computers or terminal devices.

[0125] The video module 805 can decode the video input by the video interface 809, such as H.264 decoding. The video module can also encode the video collected by the display device, such as H.264 encoding of the video collected by the external camera. In addition, the main processor 801 can also decode the video input by the video interface 809, and then output the decoded image signal to the display circuit 810.

[0126] The display circuit 810 and the modulator 8111 are configured to display corresponding images. In this embodiment, the video interface 809 receives external input video source signals, and the video module 805 decodes and / or digitizes the input video source signals and outputs one or more image signals to the display circuit 810. The display circuit 810 drives the modulator 8111 to image the incident polarized light according to the input image signal, and then outputs at least two third light beams. In addition, the main processor 801 can also output one or more image signals to the display circuit 810.

[0127] In this embodiment, the display circuit 810 and the modulator 8111 belong to the electronic elements in the modulation unit 230, and the display circuit 810 can be referred to as a driving circuit.

[0128] The power module 806 is configured to provide power for the main processor 801 and the illumination light source 111 according to input power (e.g. direct current). The power module 806 can include a rechargeable battery, which can provide power for the main processor 801 and the illumination light source 111. The light emitted by the illumination light source 111 can be transmitted to the light modulation device 112 for imaging, thereby forming an image light signal.

[0129] The wireless communication module 807 can enable the display device to communicate with the outside world wirelessly. The wireless communication module 807 can provide a wireless communication solution such as a wireless local area network (WLAN) (e.g. a wireless fidelity (Wi-Fi) network), Bluetooth (BT), a global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR) technology, etc. The wireless communication module 807 can be one or more devices integrated with at least one communication processing module. The wireless communication module 807 receives electromagnetic waves via an antenna, frequency-modulates and filters the electromagnetic wave signals, and sends the processed signals to the main processor 801. The wireless communication module 807 can also receive signals to be sent from the main processor 801, frequency-modulate them, amplify them, and radiate them as electromagnetic waves via the antenna.

[0130] In addition, the video data decoded by the video module 805 can be received wirelessly by the wireless communication module 807 or read from an external memory in addition to being input via the video interface 809. For example, the display device can receive video data from a terminal device or a vehicle entertainment system via a wireless local area network in the vehicle. The display device can also read audio and video data stored in an external memory.

[0131] The display device described above can be installed in a vehicle. Please refer to Figure 9 , Figure 9 which is a possible functional framework diagram of a vehicle provided by an embodiment of the present application.

[0132] As shown in Figure 9 , the functional framework of the vehicle can include various subsystems, such as the sensor system 12, the control system 14, one or more peripheral devices 16 (one is shown as an example), the power supply 18, the computer system 20, and the head-up display system 32. Optionally, the vehicle can also include other functional systems, such as an engine system for providing power for the vehicle, etc., which are not limited herein.

[0133] The sensor system 12 can include a number of sensing devices that can sense information of a measurement and convert the sensed information into an electrical signal or other desired form of information output according to a certain rule. As shown, the sensing devices can include a global positioning system (GPS), a vehicle speed sensor, an inertial measurement unit (IMU), a radar unit, a laser range finder, a camera, a wheel speed sensor, a steering sensor, a gear sensor, or other elements for automatic detection, etc., without limitation.

[0134] The control system 14 can include a number of elements, such as a steering unit, a braking unit, an illumination system, an automatic driving system, a map navigation system, a network time system, and an obstacle avoidance system, as shown. Optionally, the control system 14 can also include elements such as a throttle controller for controlling the driving speed of the vehicle and an engine controller, without limitation.

[0135] The peripheral device 16 can include a number of elements, such as a communication system, a touch screen, a user interface, a microphone, and a speaker, as shown. The communication system is used to realize network communication between the vehicle and other devices other than the vehicle. In actual applications, the communication system can realize network communication between the vehicle and other devices by using wireless communication technology or wired communication technology. The wired communication technology can refer to communication between the vehicle and other devices by using a network cable or an optical fiber, etc.

[0136] The power supply 18 represents a system for providing power or energy for the vehicle, which can include but is not limited to rechargeable lithium batteries or lead-acid batteries, etc. In actual applications, one or more battery components in the power supply are used to provide power or energy for starting the vehicle, and the types and materials of the power supply are not limited.

[0137] A number of functions of the vehicle are controlled and realized by the computer system 20. The computer system 20 can include one or more processors 2001 (one processor is shown as an example) and a memory 2002 (also referred to as a storage device). In actual applications, the memory 2002 can be inside the computer system 20, or can be outside the computer system 20, such as a cache in the vehicle, etc., without limitation. The processor 2001 can include one or more general-purpose processors, such as a graphic processing unit (GPU). The processor 2001 can be used to run a related program or an instruction corresponding to the program stored in the memory 2002 to realize the corresponding functions of the vehicle.

[0138] The memory 2002 can include volatile memory (such as RAM), non-volatile memory (such as ROM, flash memory, HDD, or solid-state drive SSD), or a combination of the above. The memory 2002 can be used to store a set of program codes or instructions corresponding to the program codes, so that the processor 2001 can call the program codes or instructions stored in the memory 2002 to realize the corresponding functions of the vehicle. The functions include, but are not limited to Figure 9 In this application, a set of program codes for vehicle control can be stored in the memory 2002, and the processor 2001 can control the vehicle to travel safely by calling the program codes. How to realize the safe driving of the vehicle will be described in detail below.

[0139] Optionally, in addition to storing program codes or instructions, the memory 2002 can also store information such as road maps, driving routes, sensor data, etc. The computer system 20 can realize the related functions of the vehicle in combination with other elements in the vehicle function framework diagram, such as sensors in the sensor system, GPS, etc. For example, the computer system 20 can control the driving direction or driving speed of the vehicle based on the data input of the sensor system 12, which is not limited in this application.

[0140] The head-up display system 32 can include several elements, such as the front windshield, the controller, and the head-up display (i.e., the aforementioned head-up display device). The controller is used to generate an image (such as an image containing the vehicle status such as speed, power / oil, etc. and an image containing AR content) according to the user's instruction and send the image to the head-up display for display; the head-up display can include an image generation unit, a reflection / reflection component, and the front windshield is used to cooperate with the head-up display to realize the optical path of the head-up display system to present the target image in front of the driver. It should be noted that the functions of some elements in the head-up display system can also be realized by other subsystems of the vehicle, for example, the controller can also be an element in the control system.

[0141] In this application, Figure 9 It is shown that the vehicle includes four subsystems, the sensor system 12, the control system 14, the computer system 20, and the head-up display system 32, which are only examples and do not constitute a limitation. In actual applications, the vehicle can combine several elements in the vehicle according to different functions to obtain a corresponding subsystem with different functions. In actual applications, the vehicle can include more or fewer systems or elements, which are not limited in this application.

[0142] The above vehicle can be a car, a truck, a motorcycle, a bus, a ship, an airplane, a helicopter, a lawnmower, an amusement vehicle, a playground vehicle, a construction equipment, a trolley, a golf cart, a train, a handcart, etc., and the present application is not particularly limited.

[0143] Unless otherwise defined, technical terms or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. As used herein, the articles "a", "an" and "the" are intended to mean one or more of the items that they are used to describe. As used herein, the term "includes" and / or "including" means, without limitation, encompassing, containing or comprising, and the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. As used herein, the term "another" means at least one, and the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

[0144] The above only describes one of the embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made on the basis of the present application shall be included in the protection scope of the present application.

Claims

1. A projection device, characterized by The image light generating unit, the polarization light splitting unit, the projection unit and the light detecting unit are included. The image light generating unit is configured to generate image light, which is linearly polarized light. The polarization light splitting unit is configured to emit the image light from the image light generating unit to the projection unit. The projection unit is configured to emit image light from the polarization light splitting unit, emit ambient light to the polarization light splitting unit, the ambient light being linearly polarized light, and change the polarization direction of one of the received image light and the ambient light, so that the polarization direction of the image light received by the projection unit is different from the polarization direction of the ambient light emitted by the projection unit. The polarization light splitting unit is further configured to emit the ambient light from the projection unit to the light detecting unit. The light detecting unit is configured to detect the intensity of the ambient light from the polarization light splitting unit. The projection unit includes a polarization direction control component and a projection component.

2. The projection apparatus according to claim 1, wherein The polarization direction control component is configured to change the polarization direction of the image light from the image light generating unit from a first polarization direction to a second polarization direction, emit the image light of the second polarization direction to the projection component, and emit the ambient light from the projection component to the light detecting unit without changing the polarization direction, the polarization direction of the ambient light being the second polarization direction; or The polarization direction control component is configured to emit the image light from the image light generating unit to the projection component without changing the polarization direction, change the polarization direction of the ambient light from the projection component from a first polarization direction to a second polarization direction, and emit the ambient light of the second polarization direction to the light detecting unit, the polarization direction of the image light being the first polarization direction. The first polarization direction and the second polarization direction are perpendicular. The polarization direction control component includes a half-wave plate and an optical rotator, which are sequentially located on an optical path between the polarization light splitting unit and the projection component.

3. The projection apparatus according to claim 2, wherein The half-wave plate is configured to rotate the polarization direction of a first light beam by 45 degrees along a first direction, and rotate the polarization direction of a second light beam by 45 degrees along a second direction. The optical rotator is configured to rotate the polarization direction of the first light beam by 45 degrees along the first direction, and rotate the polarization direction of the second light beam by 45 degrees along the first direction. The first direction and the second direction are opposite, the first light beam is the light of the image light and the ambient light whose polarization direction changes after passing through the projection unit, and the second light beam is the light of the image light and the ambient light whose polarization direction does not change after passing through the projection unit. The projection component includes a lens; or 4. The projection apparatus according to claim 2 or 3, characterized in that, The projection component includes a lens and a polaroid, which are sequentially located on an exit light path of the image light from the polarization direction control component. The image light generating unit includes an illumination light source and a light modulation device, 5. The projection apparatus according to any one of claims 1 to 4, wherein, The illumination light source is configured to provide a third light beam. ​ The light modulation device is configured to modulate at least part of the third light beam to obtain the image light.

6. The projection apparatus according to claim 5, wherein The light modulation device comprises a reflective spatial light modulator, and the polarization beam splitting unit has a beam splitting surface. The illumination light source and the light detection unit are located on one side of the beam splitting surface, and the reflective spatial light modulator is located on the other side of the beam splitting surface. The illumination light source and the light detection unit are located on one side of the beam splitting surface, and the reflective spatial light modulator is located on the other side of the beam splitting surface.

7. The projection apparatus according to claim 6, wherein The polarization beam splitting unit is further configured to split the third light beam into a fourth light beam and a fifth light beam, and to direct the fourth light beam to the light modulation device and the fifth light beam to the light detection unit. The light detection unit comprises a filter and a first light detection device. The filter is configured to direct the fifth light beam from the polarization beam splitting unit to a position outside the first light detection device, and to direct light in a target wavelength range from the ambient light from the polarization beam splitting unit to the first light detection device, the target wavelength range being non-overlapping with the wavelength of the fifth light beam. The first light detection device is configured to detect the intensity of the ambient light from the polarization beam splitting unit.

8. The projection apparatus according to claim 7, wherein The light detection unit further comprises a second light detection device, The filter is configured to direct the fifth light beam from the polarization beam splitting unit to the second light detection device. The second light detection device is configured to detect the intensity of the fifth light beam from the polarization beam splitting unit.

9. The projection apparatus of claim 6, wherein The polarization beam splitting unit is further configured to direct the third light beam to the light modulation device. The light detection unit comprises a first light detection device configured to detect the intensity of the ambient light from the polarization beam splitting unit.

10. The projection apparatus according to any one of claims 5 to 9, wherein, The light modulation device comprises a liquid crystal on silicon modulator, or the light modulation device comprises a micro-electro-mechanical system (MEMS) modulator and a 1 / 4 wave plate, the 1 / 4 wave plate being located on an optical path between the MEMS modulator and the polarization beam splitting unit.

11. The projection apparatus according to any one of claims 1 to 10, wherein, The polarization beam splitting unit comprises a polarization beam splitting prism.

12. A display device, characterized by comprising: The projection device comprises a main processor configured to send image data to the projection device.

13. The display device of claim 12, wherein, The projection device further comprises: a reflecting device configured to reflect and image the image light projected by the projection device to form an image.

14. The display device of claim 12, wherein, The projection device is configured to project the image light to a windshield to form an image.

15. A vehicle, characterized by The display device comprises the projection device. The display device comprises the projection device.

Images