Optical system and HUD device for naked-eye 3D imaging

Abstract

The present invention provides an optical system and HUD device for naked-eye 3D imaging, which belongs to the naked-eye 3D technology, including: an image source device, a spectroscopic unit and an optical path folding device; the optical path folding device is used to fold the second polarized light, and make the second polarized light pass through the spectroscopic unit again to form a second imaging light. The optical system for naked-eye 3D imaging provided by the present application, because the second polarized light is folded by the optical path folding device, the optical path of the second polarized light to form the second imaging light is greater than the optical path of the first polarized light to form the first imaging light, so that the first imaging light and the second imaging light entering the viewer's eyes form a depth of field effect, thereby achieving the naked-eye 3D effect. In addition, the optical system for naked-eye 3D imaging provided by the present application has a simple structure, and the observer does not need to stand in a specific position during the observation process to produce the naked-eye 3D effect. The present application separates the two polarized light beams into different optical paths to achieve the naked-eye 3D effect when incident on the human eye.

Description

Technical Field

[0001] The present invention relates to naked-eye 3D technology, and in particular to an optical system and HUD device for naked-eye 3D imaging. Background Art

[0002] Naked-eye 3D, also known as Autostereoscopy, is a technology that can achieve a three-dimensional visual effect without the aid of external tools such as polarized glasses. Naked-eye 3D technology mainly uses the structure of the screen itself and special display technology to make the left and right eyes only see specific pixels on the screen, thus producing a realistic three-dimensional image effect.

[0003] The most popular naked-eye 3D technology is cylindrical prism naked-eye 3D technology. The cylindrical lens technology is also called micro-cylindrical lens 3D technology. The three-dimensional display based on the principle of binocular parallax (i.e., spectroscopic display), especially the naked-eye spectroscopic display technology, has begun to be applied to HUD. The naked-eye spectroscopic display technology improves slightly different images for the observer's left and right eyes respectively, deceiving the observer's brain, so that the observer can produce 3D visual effects without wearing three-dimensional glasses, such as Figure 1 As shown, it is a light barrier type stereoscopic display technology. The display 101 (i.e., the image source) includes two types of pixel points, which are represented as VaR and VaL respectively. VaR is used to emit light carrying right eye image information (hereinafter referred to as right eye light), and VaL is used to emit light carrying left eye image information (hereinafter referred to as left eye light). The parallax barrier structure 102 is located on the light-emitting side of the display 101. When it is in an ideal position relative to the display 101 and relative to the observer's eyes, the observer's right eye can almost only receive the right eye light emitted by VaR, and the observer's left eye can almost only receive the left eye light emitted by VaL. In this way, the observer's left eye and right eye respectively see different images, so that the observer has a visual effect of watching a 3D image.

[0004] The above-mentioned light barrier type stereoscopic display technology requires that the parallax barrier structure is located at the display and the observer's eyes are at a certain ideal position, so that the observer's right eye can almost only receive the right eye light emitted by VaR, and the observer's left eye can almost only receive the left eye light emitted by VaL. That is, the parallax barrier structure, the display and the observer's eyes need to be at a specific angle position to enable the observer to have a visual effect of viewing a 3D image. This technology has many limitations, and the errors in the implementation process need to be controlled so that the parallax barrier structure, the image source and the observer's eyes can meet the specific angle position as much as possible. Summary of the invention

[0005] Based on the above situation, the main purpose of the present invention is to provide an optical system and HUD device for naked-eye 3D imaging, so as to solve the technical problem in the related art that the parallax barrier structure, the image source and the observer's binoculars are not in the same ideal angle position, and the observer needs to stand at a specific angle to watch the display, which makes it inconvenient to form naked-eye 3D at all angles.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present application provides an optical system for naked-eye 3D imaging, comprising:

[0008] An image source device, a light splitting unit and an optical path folding device;

[0009] The image source device is used to emit a first polarized light having a first polarization direction and a second polarized light having a second polarization direction, wherein the first polarization direction and the second polarization direction are perpendicular to each other;

[0010] The light splitting unit is arranged in the propagation direction of the first polarized light and the second polarized light, and the light splitting unit is used to reflect the first polarized light and form a first imaging light to propagate to the eye box;

[0011] The light splitting unit is further used to allow the second polarized light to pass through;

[0012] The optical path folding device is arranged in the propagation direction of the second polarized light passing through the spectroscopic unit, and the optical path folding device is used to fold the second polarized light after passing through the spectroscopic unit, and make the second polarized light after the folding process pass through the spectroscopic unit again to be emitted to form a second imaging light, so as to propagate to the eye box, so that the optical path of the second polarized light propagating to form the second imaging light is greater than the optical path of the first polarized light propagating to form the first imaging light, so that the first imaging light and the second imaging light constitute optical depth of field imaging.

[0013] Preferably, the optical path folding device is a reflection component, which includes at least one pair of polarization light conversion units, and the polarization light conversion unit is configured to be able to convert the first polarization light and the second polarization light into each other; the at least one pair of polarization light conversion units is arranged on the propagation path of the second polarization light, one of the pair of polarization light conversion units converts the second polarization light into the first polarization light, and the other polarization light conversion unit converts the converted first polarization light again into the second polarization light; the second polarization light passes through the splitting unit, and is converted multiple times by the at least one pair of polarization light conversion units to form the second polarization light again, and then is emitted through the splitting unit to form the second imaging light.

[0014] Preferably, the first polarized light is P light, and the second polarized light is S light; the spectroscopic unit includes a first surface and a second surface, and the P light is reflected on the first surface after being incident on the first surface to form the first imaging light, and the S light is emitted through the first surface and the second surface; the polarized light conversion unit includes a 1 / 4 wave plate and a reflector, and the 1 / 4 wave plate and the reflector are used to convert the S light and the P light into each other.

[0015] Preferably, the polarization light conversion unit is arranged as a pair, including a first polarization light conversion unit and a second polarization light conversion unit, the S light passing through the splitter unit is first processed by the 1 / 4 wave plate of the first polarization light conversion unit into left-handed circularly polarized light, the left-handed circularly polarized light is then reflected by a reflector to form right-handed circularly polarized light, the right-handed circularly polarized light is again processed by the 1 / 4 wave plate into P light, the P light is reflected by the second surface of the splitter unit and enters the 1 / 4 wave plate of the second polarization light conversion unit, after processing, it forms right-handed circularly polarized light, the right-handed circularly polarized light is then reflected by a reflector to form left-handed circularly polarized light, the left-handed circularly polarized light is again processed by the 1 / 4 wave plate into S light, the S light is emitted through the second surface and the first surface of the splitter unit to form the second imaging light.

[0016] Preferably, the P light and the S light incident on the light splitting unit are arranged in parallel, and the first imaging light and the second imaging light emitted by the light splitting unit are parallel.

[0017] Preferably, the splitting unit is tilted at an angle of 45 degrees relative to the polarization unit, the polarization unit is located on one side of the first surface of the splitting unit, the first polarization light conversion unit is arranged on one side of the second surface of the splitting unit and the setting direction is parallel to the setting direction of the polarization unit, and the second polarization light conversion unit is arranged on the second surface of the reflecting unit and on one side of the first polarization light conversion unit and the setting direction is perpendicular to the setting direction of the first polarization light conversion unit.

[0018] Preferably, the first imaging light and the second imaging light carry the same image information, and the first imaging light and the second imaging light are both suitable for incident on the left and right eyes of the viewer at the same time.

[0019] Preferably, the image source device comprises an image source and a polarization unit, the image source is used to emit light, and the polarization unit is used to process the light into the first polarized light and the second polarized light.

[0020] Preferably, the light splitting unit is a polarizer or a light splitting prism.

[0021] Preferably, the P light passing through the polarization unit is reflected at a Brewster angle on the first surface of the light splitting unit.

[0022] In a second aspect, the present application provides a HUD device, comprising the above-mentioned optical system for naked-eye 3D imaging.

[0023] Beneficial effects:

[0024] The present application provides an optical system for naked-eye 3D imaging, in which a first polarized light and a second polarized light having perpendicular polarization directions are emitted by an image source device, a spectrometer is arranged in the propagation direction of the first polarized light and the second polarized light, the spectrometer can emit the first polarized light to form a first imaging light, and can also allow the second polarized light to pass through, and an optical path folding device is arranged in the propagation direction of the second polarized light passing through the spectrometer, the optical path folding device is arranged to be able to fold the second polarized light, and allow the second polarized light to pass through the spectrometer again to be emitted to form a second imaging light. Since the second polarized light is folded by the optical path folding device, the optical path path of the second polarized light to form the second imaging light is greater than the optical path of the first polarized light to form the first imaging light, so that the first imaging light and the second imaging light entering the left and right eyes of the viewer form a depth of field effect, thereby achieving the naked-eye 3D effect. There is no need to make the two polarized lights enter the left and right eyes separately, and there is no need to observe at a specific angle to produce the naked-eye 3D effect in the observer's eyes. The structure is simple, and the observer does not need to stand in a specific position during the observation process to produce the naked-eye 3D effect. The present application achieves the naked-eye 3D effect when the two polarized lights are incident on the human eye by separating the two polarized lights into different optical paths.

[0025] In addition, compared with the naked-eye 3D solution in the prior art, the left and right eyes are required to view different imaging lights, which limits the distance between the human eye and the optical system. At the same time, the angle and position between the parallax barrier structure and the display need to be precisely installed. Since the present application uses different optical paths to achieve the depth of field effect, there is no need to distinguish between the imaging lights viewed by the left and right eyes, and the light folding device is installed on the propagation path of the second polarized light. As long as the second polarized light can be emitted again through the splitting unit, there is no need to limit the distance from the human eye to the optical system. As long as the human eye can receive the imaging light, the naked-eye 3D effect can be achieved, which increases the application scenarios and scope of naked-eye 3D and improves the user experience.

[0026] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred embodiments of the optical system and HUD device for naked-eye 3D imaging of the present invention will be described below with reference to the accompanying drawings.

[0028] Figure 1 It is a schematic diagram of the imaging principle of naked-eye 3D in the related art;

[0029] Figure 2 It is a schematic diagram of the structure of an optical system for naked-eye 3D imaging according to a preferred embodiment of the present invention.

[0030] 101. display; 102. parallax barrier structure;

[0031] 1. Polarization unit; 2. Spectral unit; 3. First polarization light conversion unit; 4. Second polarization light conversion unit; 5. 1 / 4 wave plate; 6. Reflector; 7. Light path folding device. DETAILED DESCRIPTION

[0032] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail. In order to avoid confusing the essence of the present invention, known methods, processes, procedures, and components are not described in detail.

[0033] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0034] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0035] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0036] In the related art, naked-eye spectral stereoscopic display technology is used to achieve naked-eye 3D effect. Naked-eye spectral stereoscopic display technology deceives the observer's brain by enhancing slightly different images for the observer's left eye and right eye respectively, so that the observer can produce 3D visual effect without wearing 3D glasses. Figure 1As shown, it is a light barrier type stereoscopic display technology. The display 101 includes two types of pixels, respectively represented as VaR and VaL. VaR is used to emit light carrying right eye image information (hereinafter referred to as right eye light), and VaL is used to emit light carrying left eye image information (hereinafter referred to as left eye light). The parallax barrier structure 102 is located on the light-emitting side of the display 101. When it is in an ideal position relative to the display 101 and relative to the observer's eyes, the observer's right eye can almost only receive the right eye light emitted by VaR, and the observer's left eye can almost only receive the left eye light emitted by VaL. In this way, the observer's left eye and right eye respectively see different images, so that the observer has a visual effect of watching a 3D image. In this technology, the parallax barrier structure 102 needs to be in an ideal position relative to the display 101 and between the observer's eyes to achieve the naked-eye 3D effect. In order to overcome the fact that the observer can only observe the naked-eye 3D effect at a specific angle, the present application provides an optical system for naked-eye 3D imaging, which will be specifically described in the embodiments below.

[0037] Example 1

[0038] The present application embodiment provides a specific implementation of an optical system for naked-eye 3D imaging, such as Figure 2 As shown, it includes an image source device, a spectroscopic unit 2 and an optical path folding device, wherein the image source device is used to emit a first polarized light and a second polarized light with perpendicular polarization directions, the spectroscopic unit 2 is arranged in the propagation direction of the first polarized light and the second polarized light, the spectroscopic unit 2 is used to reflect the first polarized light and form a first imaging light to propagate to the eye box, and the spectroscopic unit 2 allows the second polarized light to pass through, the optical path folding device is arranged in the propagation direction of the second polarized light passing through the spectroscopic unit 2, the optical path folding device is used to fold the second polarized light passing through the spectroscopic unit 2, and make the folded second polarized light pass through the spectroscopic unit 2 again to emit to form a second imaging light to propagate to the eye box, the second polarized light is folded by the optical path folding device, so the optical path of the second polarized light to form the second imaging light is greater than the optical path of the first polarized light to form the first imaging light, due to the difference in optical paths, the first imaging light and the second imaging light entering the left and right eyes of the viewer form a depth of field effect, thereby achieving the naked eye 3D effect.

[0039] In this embodiment, the optical path folding device is a reflection component, which includes at least one pair of polarization light conversion units. The polarization light conversion unit can convert the first polarization light and the second polarization light into each other. For example, the first polarization light can be converted into the second polarization light after passing through the polarization light conversion unit and emitted. The polarization light conversion unit is arranged on the propagation path of the second polarization light. The second polarization light passes through the splitting unit 2 and reaches one of the polarization light conversion units, which converts the second polarization light into the first polarization light. The converted first polarization light goes to the other polarization light conversion unit and is converted into the second polarization light again and emitted from the splitting unit 2 to form the second imaging light.

[0040] Furthermore, the first polarized light is P light, the second polarized light is S light, and the light splitting unit 2 includes a first surface and a second surface. Figure 2 As shown, the inner and outer sides of one side surface of the spectrometer unit 2 form a first surface and a second surface respectively. After the P light enters the spectrometer unit 2, it is reflected on the first surface to form a first imaging light. The S light passes through the first surface, is converted into P light by a polarization light conversion unit, and is reflected on the second surface to another polarization light conversion unit. The converted P light is converted into S light here and is emitted through the spectrometer unit 2 to form a second imaging light.

[0041] Specifically, Figure 2 As shown, the polarization light conversion unit includes a 1 / 4 wave plate 5 and a reflector 6. The S light passes through the 1 / 4 wave plate 5 to form left-handed circularly polarized light, and the left-handed circularly polarized light is reflected by the reflector 6 to form right-handed circularly polarized light. The right-handed circularly polarized light passes through the 1 / 4 wave plate 5 again to form P light. Similarly, the P light passes through the 1 / 4 wave plate 5 to form right-handed circularly polarized light, and the right-handed circularly polarized light is reflected by the reflector 6 to form left-handed circularly polarized light. The left-handed circularly polarized light passes through the 1 / 4 wave plate 5 again to form S light. In this embodiment, the polarization light conversion unit is set as a pair, including a first polarization light conversion unit and a second polarization light conversion unit. The S light passing through the splitter unit 2 is first processed by the 1 / 4 wave plate 5 of the first polarization unit 1 into left-handed circularly polarized light, and the left-handed circularly polarized light is then reflected by the reflector 6 to form right-handed circularly polarized light. The right-handed circularly polarized light is processed by the 1 / 4 wave plate 5 again to become P light. The P light is reflected by the second surface of the splitter unit 2 and enters the 1 / 4 wave plate 5 of the second polarization unit 1. After processing, it forms right-handed circularly polarized light. The right-handed circularly polarized light is then reflected by the reflector 6 to form left-handed circularly polarized light. The left-handed circularly polarized light is processed by the 1 / 4 wave plate 5 again to become S light. The converted S light is transmitted through the second surface and the first surface of the splitter unit 2 to complete the emission to form the second imaging light.

[0042] In some other embodiments, the polarization light conversion component can also be a 1 / 2 wave plate and a reflector 6. The 1 / 2 wave plate can directly convert P light into S light, or convert S light into P light. By setting multiple groups of 1 / 2 wave plates and reflectors 6, as long as the light that finally enters the light splitting unit 2 is S light, the light can be emitted, so that the optical path of the second polarized light is greater than the optical path of the first polarized light. Of course, the polarization light conversion component can also be other devices or components, as long as it can change the vibration frequency of light so that P light and S light can be converted into each other, and this application does not limit this.

[0043] In some other embodiments, the optical path folding device can also use Pancake technology (folded optical path technology) to fold the optical path of the second polarized light. Pancake technology uses multiple folding parts, each part contains a series of plane or aspherical mirrors, prisms or lenses and other elements.

[0044] In this embodiment, the P light and S light incident on the spectroscopic unit 2 are parallel, the P light and S light emitted from the spectroscopic unit 2 are parallel, and finally the first imaging light and the second imaging light emitted from the spectroscopic unit 2 are also parallel, so that the observer can form a 3D pattern with the P light and S light with different optical paths at a better angle, thereby improving the observer's viewing effect.

[0045] In this embodiment, Figure 2 As shown, the light splitting unit 2 is tilted at an angle of 45 degrees relative to the polarization unit 1, the polarization unit 1 is located on the first side of the light splitting unit 2, the first polarization light conversion unit 3 and the second polarization light conversion unit 4 are both arranged on the second side of the light splitting unit 2, wherein the arrangement direction of the first polarization light conversion unit 3 is parallel to the arrangement direction of the polarization unit 1, and the arrangement direction of the second polarization light conversion unit 4 is perpendicular to the arrangement direction of the first polarization light conversion unit 3. Figure 2 The middle dotted line is S light. It can be seen that after passing through the first polarization light conversion unit 3, the S light is reflected again at the second surface of the splitter unit 2 at an angle of 45 degrees to the second polarization light conversion unit 4, processed into S light, and then reflected to the splitter unit 2, and then emitted from the splitter unit 2 through the second surface.

[0046] In this embodiment, the image source device includes an image source (not shown in the figure) and a polarization unit 1. The image source is used to emit light with an image, and the polarization unit 1 is used to process the light into a first polarized light and a second polarized light. Specifically, the polarization unit 1 is a polarizer.

[0047] In this embodiment, the light splitting unit 2 is a polarizing plate or a light splitting prism. Specifically, this embodiment adopts a light splitting prism.

[0048] In this embodiment, the P light passing through the polarization unit 1 is reflected at the Brewster angle on the first surface of the spectroscopic unit 2. The Brewster angle allows the P light to be reflected at a specific angle on the first surface of the spectroscopic unit 2 when incident, generating linearly polarized light and improving visual clarity.

[0049] In this embodiment, the inner and outer sides of the inclined surface of the beam splitter prism form a first surface and a second surface. Figure 2 As shown, P light is directly reflected on the first surface to form the first imaging light, and S light passes through the first surface and the second surface, forming P light at the first polarization light conversion unit 3, and is reflected on the second surface to the second polarization light conversion unit 4 to form S light. The converted S light is emitted through the second surface to form the second imaging light.

[0050] Example 2

[0051] This embodiment provides a specific implementation of a HUD device, including the optical system for naked-eye 3D imaging in Embodiment 1. In this embodiment, the HUD device is applied in a head-up display of a car.

[0052] According to an optical system for naked-eye 3D imaging provided by this example, a first polarized light and a second polarized light with perpendicular polarization directions are emitted by an image source device, and a spectrometer is arranged in the propagation direction of the first polarized light and the second polarized light. The spectrometer can emit the first polarized light to form a first imaging light, and can also allow the second polarized light to pass through. An optical path folding device is arranged in the propagation direction of the second polarized light passing through the spectrometer, and the optical path folding device is arranged to be able to fold the second polarized light, and allow the second polarized light to pass through the spectrometer again to form a second imaging light. Since the second polarized light is folded by the optical path folding device, the optical path path of the second polarized light to form the second imaging light is greater than the optical path of the first polarized light to form the first imaging light, so that the first imaging light and the second imaging light entering the left and right eyes of the viewer form a depth of field effect, thereby achieving the naked-eye 3D effect. There is no need to make the two polarized lights enter the left and right eyes separately, and there is no need to observe at a specific angle to produce the naked-eye 3D effect in the observer's eyes. The structure is simple, and the observer does not need to stand in a specific position during the observation process to produce the naked-eye 3D effect. The present application achieves the naked-eye 3D effect when the two polarized lights are incident on the human eye by separating the two polarized lights into different optical paths.

[0053] In addition, compared with the naked-eye 3D solution in the prior art, the left and right eyes are required to view different imaging lights, which limits the distance between the human eye and the optical system. At the same time, the angle and position between the parallax barrier structure and the display need to be precisely installed. Since the present application uses different optical paths to achieve the depth of field effect, there is no need to distinguish between the imaging lights viewed by the left and right eyes, and the light folding device is installed on the propagation path of the second polarized light. As long as the second polarized light can be emitted again through the splitting unit, there is no need to limit the distance from the human eye to the optical system. As long as the human eye can receive the imaging light, the naked-eye 3D effect can be achieved, which increases the application scenarios and scope of naked-eye 3D and improves the user experience.

[0054] Those skilled in the art will appreciate that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0055] It should be understood that the above-mentioned embodiments are merely illustrative and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will all be included in the scope of the claims of the present invention.

Claims

1. An optical system for naked-eye 3D imaging, characterized in that: include: Image source device, light splitting unit (2) and light path folding device (7); The image source device is used to emit a first polarized light having a first polarization direction and a second polarized light having a second polarization direction, wherein the first polarization direction and the second polarization direction are perpendicular to each other; The light splitting unit (2) is arranged in the propagation direction of the first polarized light and the second polarized light, and the light splitting unit (2) is used to reflect the first polarized light and form a first imaging light to propagate to the eye box; The light splitting unit (2) is also used to allow the second polarized light to pass through; The optical path folding device (7) is arranged in the propagation direction of the second polarized light passing through the light splitting unit (2), and the optical path folding device (7) is used to fold the second polarized light after passing through the light splitting unit (2), and make the second polarized light after the folding process pass through the light splitting unit (2) again to be emitted to form a second imaging light, so as to propagate to the eye box, so that the optical path of the second polarized light propagating to form the second imaging light is greater than the optical path of the first polarized light propagating to form the first imaging light, so that the first imaging light and the second imaging light form an optical depth of field imaging; the optical path folding device is a reflection component, and the reflection component includes at least one The polarization conversion unit is configured to be able to convert the first polarization light into the second polarization light; the at least one pair of polarization conversion units is arranged on the propagation path of the second polarization light, one of the pair of polarization conversion units converts the second polarization light into the first polarization light, and the other polarization conversion unit converts the converted first polarization light into the second polarization light again; the second polarization light passes through the light splitting unit (2), and then is converted multiple times by the at least one pair of polarization conversion units to form the second polarization light again, and then is emitted through the light splitting unit (2) to form the second imaging light.

2. The optical system for naked-eye 3D imaging according to claim 1, characterized in that: The first polarized light is P light, and the second polarized light is S light; the light splitting unit (2) comprises a first surface and a second surface, the P light is incident on the first surface and is reflected on the first surface to form the first imaging light, and the S light is emitted through the first surface and the second surface; the polarized light conversion unit comprises a quarter wave plate (5) and a reflector (6), and the quarter wave plate (5) and the reflector (6) are used to convert the S light and the P light into each other.

3. The optical system for naked-eye 3D imaging according to claim 2, characterized in that: The polarization conversion unit is arranged as a pair, comprising a first polarization conversion unit (3) and a second polarization conversion unit (4); the S light passing through the light splitting unit (2) is first processed by a quarter wave plate (5) of the first polarization conversion unit (3) into left-handed circularly polarized light; the left-handed circularly polarized light is then reflected by a reflector (6) to form right-handed circularly polarized light; the right-handed circularly polarized light is again processed by the quarter wave plate (5) into P light; the P light is reflected by the second surface of the light splitting unit (2) and enters the quarter wave plate (5) of the second polarization conversion unit (4); after being processed, it forms right-handed circularly polarized light; the right-handed circularly polarized light is then reflected by the reflector (6) to form left-handed circularly polarized light; the left-handed circularly polarized light is again processed by the quarter wave plate (5) into S light; the S light is transmitted through the second surface and the first surface of the light splitting unit (2) to be emitted to form the second imaging light.

4. The optical system for naked-eye 3D imaging according to claim 3, characterized in that: The P light and the S light incident on the light splitting unit (2) are arranged in parallel, and the first imaging light and the second imaging light emitted by the light splitting unit (2) are parallel.

5. The optical system for naked-eye 3D imaging according to any one of claims 1 to 4, characterized in that: The first imaging light and the second imaging light carry the same image information, and the first imaging light and the second imaging light are both suitable for incident on the left and right eyes of the viewer at the same time.

6. The optical system for naked-eye 3D imaging according to any one of claims 1 to 4, characterized in that: The image source device comprises an image source and a polarization unit (1), wherein the image source is used to emit light, and the polarization unit (1) is used to process the light into the first polarized light and the second polarized light.

7. The optical system for naked-eye 3D imaging according to any one of claims 1 to 4, characterized in that: The light splitting unit (2) is a polarizing plate or a light splitting prism.

8. The optical system for naked-eye 3D imaging according to claim 6, characterized in that: The P light that passes through the polarization unit (1) is reflected at the Brewster angle on the first surface of the light splitting unit (2).

9. A HUD device, characterized in that: Comprising an optical system for naked-eye 3D imaging according to any one of claims 1-8.

Images