Naked eye augmented reality display device

Abstract

The present invention relates to a naked-eye augmented reality display device, comprising: a light source for providing multi-view images; a 3D light field screen for phase-modulating image pixels in the multi-view images to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space, so as to obtain a naked-eye 3D display; the 3D light field screen comprises at least one phase plate, on which a pixel-type nano grating is arranged; a six-axis adjustment device for six-axis adjustment of the 3D light field screen to match the pixel-type nano grating with the image pixel, which comprises a CCD real-time monitoring system and a six-axis adjustment screen frame. The display device transforms the nearly parallel light provided by the light source into a light field through the phase plate, forms a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space, and obtains a naked-eye 3D display. It can not only realize the display requirements of no image crosstalk, no visual fatigue, wide viewing angle and high diffraction efficiency, but also improve the light energy utilization rate of the device, so as to increase the brightness of the 3D light field screen.

Description

Technical Field

[0001] The invention relates to a naked-eye augmented reality display device, belonging to the technical field of optical display. Background Art

[0002] Due to the constraints of low image resolution and easy visual fatigue, naked-eye 3D display based on the parallax principle has not really entered the field of consumer electronics. Augmented Reality (AR) is a technology proposed in 1990 that "seamlessly" integrates real-world information and virtual-world information. It applies virtual information to the real world through computers and other scientific technologies, which is difficult to experience in the real world (visual, tactile, etc.), and is perceived by human senses, thereby achieving a sensory experience beyond reality. It can combine the real and virtual worlds to create a new visual environment, and has broad application prospects in important fields such as military, medical, education, games and life. Compared with the current popular AR and other augmented reality solutions, the augmented reality system that integrates free stereoscopic display technology can reduce the weight caused by auxiliary equipment to a certain extent, and provide viewers with better comfort.

[0003] Chinese patent CN201610108401.8 provides a device for naked-eye 3D augmented reality based on liquid crystal grating. Cover the surface of the liquid crystal display LCD with a blind screen, which separates images of different viewing angles into spatial angles. In theory, since ghost images and stray light are difficult to eliminate, visual fatigue is easily caused when the human eye observes 3D images. At the same time, the above method cannot arbitrarily regulate the light. Affected by stray light, the viewing angle interval is usually set large, the viewing angle is incoherent, and a jump-free naked-eye 3D display effect cannot be achieved. This patent replaces traditional liquid crystal with transparent liquid crystal to achieve the effects of naked-eye 3D and augmented reality, but it also has the above disadvantages.

[0004] Chinese patent CN201710631326.8 provides a naked-eye 3D augmented reality device for human eye tracking, which mainly utilizes a naked-eye 3D display terminal based on a microlens array combined with a semi-transparent and semi-reflective mirror to achieve the effect of augmented reality, but its field of view is small and is limited to single-person observation.

[0005] Chinese patents CN201610034105.8 and CN201510778086.5 respectively proposed a projection-type naked-eye 3D display device and a naked-eye 3D display device using a color filter. The core of these two devices is to use a pixel-type nano-grating structure to achieve light field phase modulation. The characteristic is that compared with the visual impairment method and the micro-column lens method, the influence of stray light and ghosting can be eliminated, and the viewing angle interval can be designed to be very small, forming a more continuous parallax effect, without a sense of jump when observing. Therefore, within the field of view angle range, the 3D experience effect is good. However, the color filter and the spatial separation of RGB pixels reduce the utilization rate of light energy, which ultimately leads to a decrease in the brightness of the image on the screen, and the preparation process is complicated.

[0006] In order to achieve the display requirements of no crosstalk, no visual fatigue, wide viewing angle and high diffraction efficiency in practical applications, this patent proposes a nanostructured spatially multiplexed phase plate based on the above patents. Combining the phase plate with laser projection technology can obtain an augmented reality device with naked-eye 3D light field display. Summary of the invention

[0007] The purpose of the present invention is to provide a naked-eye augmented reality display device, which can not only achieve the display requirements of no image crosstalk, no visual fatigue, wide viewing angle, and high diffraction efficiency, but also improve the light energy utilization rate of the device and increase the brightness of the 3D light field screen.

[0008] To achieve the above object, the present invention provides the following technical solution: a naked eye augmented reality display device, comprising:

[0009] A light source for providing multi-view images;

[0010] A 3D light field screen is used to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space after phase modulation of the image pixels in the multi-view image, so as to obtain a naked-eye 3D display; the 3D light field screen comprises at least one phase plate, on which a pixel-type nano-grating is provided;

[0011] The six-axis adjustment device is used to perform six-axis adjustment on the 3D light field screen so that the pixel-type nano-grating matches the image pixel. The six-axis adjustment device includes a CCD real-time monitoring system and a six-axis adjustment screen frame.

[0012] Furthermore, the light source projects RGB mixed light, and the phase plate includes a first grating, a second grating and a third grating, and the upper pixel-type nanogratings of the first grating, the second grating and the third grating are correspondingly arranged at the same position of the phase plate and matched with the image pixels to respectively perform phase control on the red light, green light and blue light in the RGB mixed light.

[0013] Furthermore, the naked-eye augmented reality display device comprises a plurality of the phase plates, and the pixel-type nano-gratings corresponding to the red light, the green light and the blue light in the mixed light are respectively located at the same pixel position of the plurality of phase plates.

[0014] Furthermore, the light source is a laser projector, and the laser projector is located on the light emitting surface of the 3D light field screen, or the laser projector is located on the backlight surface opposite to the light emitting surface.

[0015] Furthermore, the first grating, the second grating and the third grating are arranged in sequence and arranged from near to far according to the distance between them and the laser projector.

[0016] Furthermore, the pixel-type nano-grating on the same phase plate only performs phase control on monochromatic light.

[0017] Furthermore, the grating period and orientation angle of each pixel-type nano-grating are calculated according to the grating equation and satisfy the following relationship:

[0018] (1)

[0019] (2)

[0020] Among them, θ1 and denote the diffraction angle and azimuth of the diffracted light, θ and λ denote the incident angle and wavelength of the incident light, Λ and represent the period and orientation angle of the nanograting structure in the pixel-type nanograting respectively, and n represents the refractive index of the light wave in the medium.

[0021] Furthermore, the nanograting structure in the pixel-type nanograting is selected from any one of a one-dimensional nanograting structure, a two-dimensional nanograting structure, a spatial multiplexing nanograting structure, a nanograting array structure or a binary optical element.

[0022] Furthermore, the six-axis adjustment screen frame includes a pitch screen frame and a five-axis adjustment platform connected to the pitch screen frame, and a micrometer is provided at the upper end of the pitch screen frame.

[0023] Furthermore, the CCD real-time monitoring system comprises a CCD camera, and the CCD camera is arranged at four corners of the pitch screen frame to monitor the relative position of the pixel-type nano-grating and the image pixel.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The naked-eye augmented reality display device of the present invention uses a 3D light field screen to phase modulate the image pixels emitted by the light source, and transforms the nearly parallel light emitted by the light source into a light field through a phase plate, so as to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space, thereby obtaining a naked-eye 3D display; due to the focusing effect of the image, there is no crosstalk between images of different viewing angles, and the images carry amplitude and phase information at the same time, so there is no visual fatigue during observation, and there is no restriction on the observation position;

[0026] (2) No filter is set on the backlight surface of the 3D light field screen, but a phase plate with nanostructure spatial multiplexing is used to achieve color 3D display, which improves the utilization rate of light energy and increases the brightness of the 3D light field screen;

[0027] (3) The position of the 3D light field screen is adjusted by setting a six-axis adjustment device so that the pixel-type nano-grating matches the image pixel of the light source. In addition, by adopting a five-axis adjustment stage + pitch screen frame solution, a CCD camera is used to monitor the relative position of the pixel-type nano-grating and the image pixel. A micrometer is set at the upper end of the pitch screen frame, and the lower end is used as a rotation fulcrum, so that the pitch displacement can be accurately adjusted.

[0028] (4) The pixel-type nano-gratings on the same phase plate in the naked-eye augmented reality display device of the present invention only perform phase control on a single-shot light. In contrast, the prior art arranges nano-grating pixel structures corresponding to red, green and blue light on the same functional layer of the projection screen to form a pixel-type nano-grating. In the process of preparing the phase plate, the present invention only needs to produce a nano-grating structure for phase control on monochromatic light, which greatly simplifies the preparation process and reduces the process difficulty and production cost.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of the nano-grating structure in the naked-eye augmented reality display device of the present invention in the XY plane;

[0031] Figure 2 for Figure 1 The schematic diagram of the structure of the nano-grating structure shown in the XZ plane;

[0032] Figure 3 It is a structural schematic diagram of a naked-eye 3D display device in the prior art;

[0033] Figure 4 It is a structural schematic diagram of a naked-eye augmented reality display device according to an embodiment of the present invention;

[0034] Figure 5 for Figure 4 A schematic structural diagram of a 3D light field screen in a naked eye augmented reality display device is shown;

[0035] Figure 6 for Figure 4 A schematic structural diagram of a first grating in the naked-eye augmented reality display device shown;

[0036] Figure 7 for Figure 4 A schematic structural diagram of a six-axis adjustment device in a naked-eye augmented reality display device is shown;

[0037] Figure 8 Schematic diagram of the structure of a naked-eye augmented reality display device shown in another embodiment of the present invention. DETAILED DESCRIPTION

[0038] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0039] It should be noted that the terms “upper”, “lower”, “left”, “right”, “inner”, “outer”, etc. in the present invention are only used to illustrate the present invention with reference to the drawings and are not used as limiting terms.

[0040] The naked eye augmented reality display device of the present invention comprises:

[0041] The light source is preferably a laser projector, which is used for amplitude adjustment, that is, projecting multi-view images. The laser projector is located on the backlight surface (rear projection) or the light-emitting surface (front projection) of the 3D light field screen, and uses a laser light source, which has the characteristics of high brightness and excellent directivity;

[0042] A 3D light field screen is used to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space after phase modulation of the image pixels in the multi-view image, so as to obtain a naked-eye 3D display; the 3D light field screen comprises at least one phase plate, on which a pixel-type nano-grating is provided;

[0043] The six-axis adjustment device is used to perform six-axis adjustment on the 3D light field screen so that the pixel-type nano-grating matches the image pixel. The six-axis adjustment device includes a CCD real-time monitoring system and a six-axis adjustment screen frame.

[0044] In the area illuminated by a non-directional light source, the 3D light field screen of the naked-eye augmented reality display device becomes transparent, thereby achieving an augmented reality effect.

[0045] In the present invention, the pixel-type nanograting is formed by a plurality of nanograting structures, and the nanograting structure is selected from any one of a one-dimensional nanograting structure, a two-dimensional nanograting structure, a spatially multiplexed nanograting structure, a nanograting array structure or a binary optical element. In one embodiment of the present invention, the nanograting is a one-dimensional nanograting structure, and the specific details of the phase regulation of its one-dimensional grating period and orientation angle are as follows.

[0046] See also Figure 1 and Figure 2 , Figure 1 and Figure 2 The structural diagrams of the nano-grating structure in the nanometer scale in the XY plane and the XZ plane are shown respectively. According to the grating equation, the period and orientation angle of the nano-grating structure 101 satisfy the following relationship:

[0047] (1)

[0048] (2)

[0049] Among them, the light is incident on the XY plane at a certain angle, θ1 and represents the diffraction angle (the angle between the diffracted light and the positive direction of the z-axis) and the azimuth (the angle between the diffracted light and the positive direction of the x-axis) of the diffracted light 202, θ and λ represent the incident angle (the angle between the incident light and the positive direction of the z-axis) and the wavelength of the light source 201, Λ and represents the period and orientation angle (the angle between the groove direction and the positive direction of the y-axis) of the nano-grating structure 101, and n represents the refractive index of the light wave in the medium. In other words, after specifying the wavelength of the incident light, the incident angle, the diffraction angle and the diffraction azimuth of the diffracted light, the period and orientation angle of the required nano-grating structure can be calculated by the above two formulas. For example, 650nm wavelength red light is incident at an angle of 60°, the diffraction angle of the light is 10°, and the diffraction azimuth is 45°. By calculation, the corresponding period of the nano-grating structure is 550nm, and the orientation angle is -5.96°. Therefore, the grating period, orientation and azimuth are calculated according to the holographic principle and the grating equation.

[0050] According to the above principle, each or more nano-grating structures are regarded as a pixel. After making multiple pixel-type nano-gratings with different orientation angles and periods set as needed on a screen surface, theoretically, enough different viewpoints can be obtained. With the control of color and grayscale, naked-eye 3D display under multiple viewing angles can be realized. The viewing angle range of multiple pixel arrays is between plus and minus 90 degrees.

[0051] However, after the screen with the above-mentioned nano-grating structure is applied to the laser display module, the following problem exists: for light sources with different wavelengths, the corresponding nano-grating structure will have different periods. For the same directional projection screen module, if the three wavelengths of light sources R, G, and B are incident at the same angle, then the diffraction angles of the three beams of R, G, and B must be different, that is, the three beams of R, G, and B are not at the same focus. However, the realization of color graphics must rely on the combination of RGB colors (or other three colors). This means that if a three-color light source is used in a directional projection screen module, the three colors of light must be incident on the same corresponding nano-grating at different angles.

[0052] The key to solving the above technical problems is to make the three colors of RGB (or other three colors) form the same diffraction angle and the same spatial viewpoint after passing through a projecting screen module. Figure 3 In the naked-eye 3D display device disclosed in Chinese patent CN201510778086.5, a directional color filter 1, a laser light source (not shown) and a liquid crystal display panel 2 are used together to realize a color display scheme. Among them, the directional color filter 1 includes a color filter and a directional functional structure layer located on the light-emitting surface of the color filter, a plurality of filter units are provided on the color filter, and a plurality of structural units are provided on the directional functional structure layer, and the filter units and the structural units need to be arranged one by one. And its liquid crystal display panel 2 needs to be provided with a plurality of pixel units including at least three sub-pixels (red, green, and blue). Compared with the traditional visual impairment method and micro-cylindrical lens method, this design has the advantages of eliminating the influence of stray light and ghosting, the viewing angle interval can be designed to be very small, forming a relatively continuous parallax effect, and no jumping feeling when observing. However, due to the complex structure of the directional color filter 1 and the spatial separation of the pixel units of the liquid crystal display panel 2, the light energy utilization rate of the entire device is low, which ultimately leads to a decrease in the brightness of the image on the screen. Moreover, the complex structure makes the entire tissue preparation process complicated and the production cost is extremely high.

[0053] In the present invention, a nano-grating structure can be produced by etching on a phase plate using a photolithography method; or, a template for imprinting is produced, and then the nano-grating structure is imprinted by nano-imprinting technology to form a pixel-type nano-grating, thereby reducing production costs. The preparation methods are all prior art and will not be elaborated here. The photolithography technology can refer to the photolithography equipment and photolithography method recorded in the Chinese patent application with application number CN201310166341.1.

[0054] See also Figures 4 to 7 An embodiment of the present invention provides a naked eye augmented reality display device, which includes a laser projector 1-10, a 3D light field screen 1-1 and a six-axis adjustment device 1-2. Figure 4The direction indicated by the middle arrow A is the front side of the naked eye augmented reality display device, and the 3D light field screen 1-1 includes a light emitting surface 1-11 located on the front side and a backlight surface 1-12 located on the back side. Figure 5 As shown, the phase plate in the 3D light field screen 1-1 includes a first grating 1-13, a second grating 1-14 and a third grating 1-15 for phase modulation of red light, green light and blue light, respectively. The first grating 1-13, the second grating 1-14 and the third grating 1-15 are arranged in sequence from the back to the front of the device. At the same time, nano-grating structures for phase modulation of red, green and blue light are respectively arranged on the phase plate. The laser projector 1-10 is arranged in the middle and upper position of the backlight surface 1-12 (rear projection type) of the 3D light field screen 1-1, and is used to obliquely project multi-view encoded images, so that the light of each pixel is precisely separated to the corresponding horizontal viewpoint (or vertical viewpoint) through the phase modulation of the nano-grating structure on the 3D light field screen 1-1, and a 3D light field is generated in the viewpoint area, and the excess zero-order light is directly projected to the ground to prevent the laser of the projector from directly projecting into the human eye. By placing the real object behind the screen, adjusting and optimizing the virtual scene, and observing it in the viewpoint area, the effect of augmented reality can be achieved.

[0055] In this embodiment, three types of nano-grating structures corresponding to RGB wavelengths on the first grating 1-13, the second grating 1-14 and the third grating 1-15 are arranged at the same position of the phase plate. Figure 6 As shown, a plurality of array-arranged pixel-type nano-gratings 1-131 are provided on the first grating 1-13, each pixel-type nano-grating 1-131 is arranged corresponding to a single image pixel projected by the laser projector 1-10, and each pixel-type nano-grating 1-131 includes at least one nano-grating structure 1-130. The nano-grating structure 1-130 of this embodiment adopts a one-dimensional nano-grating structure, and its specific structural design has been described above. Since each phase plate in the present invention is only used to perform phase control on light of one color, in the process of preparing the phase plate, only a monochromatic nano-grating structure needs to be prepared on each phase plate, which greatly simplifies the preparation process and reduces the difficulty of preparation compared to the prior art of preparing at least three-color (red, green, and blue) nano-grating structures. By adopting the spatial multiplexing method of the present invention to perform color display, that is, the nano-grating structures corresponding to red, green and blue are prepared at the same pixel position and overlapped, and the red, green and blue mixed light incident on the nano-grating structure are phase-controlled respectively without affecting each other, thereby improving the utilization rate of light energy and increasing the display brightness of the 3D light field screen 1-1.

[0056] The 3D light field screen in this embodiment is only equipped with one phase plate. In other embodiments, multiple phase plates can be provided to perform phase control on the RGB mixed light, and the three types of nano-grating structures corresponding to the RGB wavelengths in each phase plate are arranged at the same position.

[0057] Please combine Figure 7 In order to accurately align the pixel-type nanostructure with the image pixels projected by the laser projector 1-10, it is necessary to perform six-axis adjustment on the 3D light field screen 1-1 in space, namely X, Y, Z, θx, θy, θz. The existing adjustment device sets the six-axis adjustment table below the screen. However, since the distance from the rotation point of the pitch (θy) to the pixel at the top of the screen is large, a very small rotation angle of the pitch (θy) will be converted into a larger displacement of the pixel, resulting in a misalignment. In the present invention, the six-axis adjustment device 1-2 includes a CCD real-time monitoring system (not shown) and a six-axis adjustment screen frame 1-21. Among them, the six-axis adjustment screen frame 1-21 includes a pitch screen frame 1-211 and a five-axis adjustment platform 1-212 connected thereto. A micrometer (not shown) is provided above the pitch screen frame 1-211, which is fixed on a fixed unit (not shown) connected to the pitch screen frame 1-211, and the lower end of the pitch screen frame 1-211 is used as a rotation fulcrum. The micrometer can accurately adjust the pitch (θy) displacement of the pitch screen frame 1-211. In this embodiment, the CCD real-time monitoring system includes four CCD cameras (not shown), which are respectively installed on the four corners of the 3D light field screen 1-1 to monitor the relative position of the pixel-type nanostructure on each phase plate in the 3D light field screen 1-1 and the image pixel projected by the laser projector 1-10, so as to provide a reference for the six-axis adjustment. Of course, in other embodiments, the six-axis adjustment algorithm can also be used to electrically control the adjustment platform to achieve alignment operation through the relative position fed back by the CCD camera.

[0058] The 3D light field screen in the present invention can adjust the size of a single pixel according to the resolution of the screen, and can achieve 2D / 3D switching. Multiple (n) viewing angle graphics correspond to directional pixels (n) respectively, forming a 3D image display. If it is not a multi-view image, but a single-view graphic, then a 2D display is formed, where the pixel size of the 2D image is equal to "n*directional pixel size". Since the pixel size can be very small, such as 20 microns, if there are 9 viewpoints, then the size of the 2D pixel is 60 microns, which does not affect the 2D image resolution of the display screen.

[0059] See also Figure 8Another embodiment of the naked eye augmented reality display system of the present invention is basically the same as the previous embodiment, except that the present embodiment uses a front projection laser projector 2-10, and the nano grating structure on the 3D light field screen 2-1 is also adjusted and designed accordingly. Similar to the rear projection, the present embodiment also uses an oblique projection method to eliminate the risk of laser directly hitting the human eye.

[0060] In summary:

[0061] (1) The naked-eye augmented reality display device of the present invention uses a 3D light field screen to phase modulate the image pixels emitted by the light source, and transforms the nearly parallel light emitted by the light source into a light field through a phase plate, so as to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space, thereby obtaining a naked-eye 3D display; due to the focusing effect of the image, there is no crosstalk between images of different viewing angles, and the images carry amplitude and phase information at the same time, so there is no visual fatigue during observation, and there is no restriction on the observation position;

[0062] (2) No filter is set on the backlight surface of the 3D light field screen, but a phase plate with nanostructure spatial multiplexing is used to achieve color 3D display, which improves the utilization rate of light energy and increases the brightness of the 3D light field screen;

[0063] (3) The position of the 3D light field screen is adjusted by setting a six-axis adjustment device so that the pixel-type nano-grating matches the image pixel of the light source. In addition, by adopting a five-axis adjustment stage + pitch screen frame solution, a CCD camera is used to monitor the relative position of the pixel-type nano-grating and the image pixel. A micrometer is set at the upper end of the pitch screen frame, and the lower end is used as a rotation fulcrum, so that the pitch displacement can be accurately adjusted.

[0064] (4) The pixel-type nano-gratings on the same phase plate in the naked-eye augmented reality display device of the present invention only perform phase control on a single-shot light. In contrast, the prior art arranges nano-grating pixel structures corresponding to red, green and blue light on the same functional layer of the projection screen to form a pixel-type nano-grating. In the process of preparing the phase plate, the present invention only needs to produce a nano-grating structure for phase control on monochromatic light, which greatly simplifies the preparation process and reduces the process difficulty and production cost.

[0065] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A naked eye augmented reality display device, characterized in that: include: A light source for providing multi-view images; A 3D light field screen is used to form a 3D light field observation area of ​​a dot matrix, a line matrix or a plane matrix in space after phase modulation of the image pixels in the multi-view image, so as to obtain a naked-eye 3D display; the 3D light field screen comprises at least one phase plate, on which a pixel-type nano-grating is provided; A six-axis adjustment device, used for performing six-axis adjustment on the 3D light field screen so that the pixel-type nano-grating matches the image pixel, the six-axis adjustment device comprising a CCD real-time monitoring system and a six-axis adjustment screen frame; The light source projects RGB mixed light, the phase plate comprises a first grating, a second grating and a third grating, the upper pixel-type nano-gratings of the first grating, the second grating and the third grating are correspondingly arranged at the same position of the phase plate and matched with the image pixels, so as to respectively perform phase control on the red light, the green light and the blue light in the RGB mixed light; The naked-eye augmented reality display device comprises a plurality of the phase plates, and the pixel-type nano-gratings corresponding to the red light, the green light and the blue light in the mixed light are respectively located at the same pixel position of the plurality of phase plates.

2. The naked eye augmented reality display device according to claim 1, characterized in that: The light source is a laser projector, and the laser projector is located on the light emitting surface of the 3D light field screen, or the laser projector is located on the backlight surface opposite to the light emitting surface.

3. The naked eye augmented reality display device according to claim 2, characterized in that: The first grating, the second grating and the third grating are arranged in sequence and arranged from near to far according to the distance between them and the laser projector.

4. The naked eye augmented reality display device according to any one of claims 1 to 3, characterized in that: The pixel-type nano-grating on the same phase plate only performs phase regulation on monochromatic light.

5. The naked eye augmented reality display device according to claim 1, characterized in that: The grating period and orientation angle of each pixel-type nano-grating are calculated according to the grating equation and satisfy the following relationship: (1) tanφ1=sinφ / (cosφ-nsinθ(Λ / λ)); (2) sin 2 (θ1)=(λ / Λ) 2 +(nsinθ) 2 -2nsinθcosφ(λ / Λ); Among them, θ1 and φ1 represent the diffraction angle and azimuth of the diffracted light respectively, θ and λ represent the incident angle and wavelength of the incident light respectively, Λ and φ represent the period and orientation angle of the nanograting structure in the pixel-type nanograting respectively, and n represents the refractive index of the light wave in the medium.

6. The naked eye augmented reality display device according to claim 1, characterized in that: The nanograting structure in the pixel-type nanograting is selected from any one of a one-dimensional nanograting structure, a two-dimensional nanograting structure, a spatial multiplexing nanograting structure, a nanograting array structure or a binary optical element.

7. The naked eye augmented reality display device according to claim 1, characterized in that: The six-axis adjustment screen frame comprises a pitch screen frame and a five-axis adjustment platform connected to the pitch screen frame, and a micrometer is arranged at the upper end of the pitch screen frame.

8. The naked eye augmented reality display device according to claim 7, characterized in that: The CCD real-time monitoring system comprises a CCD camera, which is arranged at the four corners of the pitch screen frame to monitor the relative position of the pixel-type nano-grating and the image pixel.

Images