Patent Publication Number: US-2023152585-A1

Title: Augmented Reality Device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage of International Application No. PCT/CN2021/081824, filed on Mar. 19, 2021, which claims priority to Chinese Patent Application No. 202010233011.X filed on Mar. 28, 2020. Both of the aforementioned applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This application relates to the display field in which virtuality and reality are combined, and in particular, to an augmented reality device. 
     BACKGROUND 
     A principle of an augmented reality (augmented reality, AR) technology is as follows: A computer-controlled image projector is used to project, into the human eye to form a virtual scene, display light that carries digital content, and the virtual scene is superposed with an external real scene that can be directly seen by the human eye, so that the human eye views image information obtained by combining the virtual scene and the external real scene. 
     In a conventional augmented reality device, because a part of display light projected by an image projector is always emitted from the augmented reality device, display light that carries digital information is leaked. Consequently, privacy of a user is leaked, and privacy of the user is reduced. 
     SUMMARY 
     This application provides an augmented reality device, to reduce a possibility that display light is emitted from the augmented reality device, prevent display light that carries digital information from being leaked, and improve privacy of a user. 
     The augmented reality device in this application includes a frame, a combiner, a laser projector, and a filter. The combiner is mounted on the frame, and the combiner includes an inner surface and an outer surface that are opposite to each other. The laser projector is mounted on the frame, and the laser projector is configured to emit a laser beam. The laser beam is display light that carries digital content. The filter is mounted on the outer surface of the combiner, and a blocking band of the filter includes a band of the laser beam. 
     After the laser beam enters the combiner, a part of the laser beam is emitted from the inner surface of the combiner, a part of the laser beam is emitted from the outer surface of the combiner, and the filter blocks the laser beam emitted from the outer surface of the combiner, to prevent the laser beam emitted from the outer surface of the combiner from passing through the filter and being emitted into an external environment, and prevent the laser beam that carries the digital content from being leaked. This may improve privacy of a user and sociality of the augmented reality device, and may further prevent the leaked display light from forming a small display window on a surface of the augmented reality device, to improve appearance refinement existing when the user uses the augmented reality device. 
     After a part of ambient light whose wavelength is outside the blocking band passes through the filter, the part of ambient light enters the combiner through the outer surface of the combiner, and is emitted from the inner surface of the combiner, so that the user can view an external real scene through the combiner and the filter, to ensure that the augmented reality device has a specific transmittance. 
     The inner surface of the combiner is a surface of the combiner that faces the user when the augmented reality device is worn on the head of the user. In other words, the inner surface of the combiner is a surface of the combiner that faces the human eye. Similarly, the outer surface of the combiner is a surface of the combiner that faces away from the user when the augmented reality device is worn on the head of the user. In other words, the outer surface of the combiner is a surface of the combiner that faces away from the human eye. In other words, the outer surface of the combiner is a surface of the combiner that faces the outside. 
     In an implementation, the outer surface of the combiner includes a light exit area, the laser beam emitted from the outer surface of the combiner is emitted from the light exit area of the outer surface of the combiner, and the filter covers the light exit area of the outer surface of the combiner, so that the laser beam emitted from the outer surface of the combiner is not emitted into the external environment, to prevent the laser beam that carries the digital content from being leaked. 
     In another implementation, the filter covers the outer surface of the combiner, to ensure appearance integrity and consistency of the augmented reality device, and improve appearance refinement of the augmented reality device. In addition, compared with a manner in which the filter covers only a light exit area of the outer surface of the combiner, the filter covers the outer surface of the combiner, so that a difficulty in a process of assembling the filter is reduced, and there is no need to perform additional processing on the filter, to reduce a difficulty in processing the filter, and reduce production costs of the filter. 
     In an implementation, the laser projector is configured to emit a red laser beam, a green laser beam, and a blue laser beam to implement color display by blending the three colors of laser beams. The blocking band of the filter includes bands of the red laser beam, the green laser beam, and the blue laser beam, to block light whose wavelength is in the bands of the red laser beam, the green laser beam, and the blue laser beam and that is in the laser beam emitted from the outer surface of the combiner. 
     In an implementation, the blocking band includes a first band, a second band, and a third band, every two of the first band, the second band, and the third band are spaced apart, the first band includes the band of the red laser beam, the second band includes the band of the green laser beam, and the third band includes the band of the blue laser beam. 
     Because the first band, the second band, and the third band are spaced apart, light whose wavelength is between the first band and the second band and light whose wavelength is between the second band and the third band can still pass through the filter to be normally propagated, to reduce an impact caused by the filter on light whose wavelength is among the bands of the red laser beam, the green laser beam, and the blue laser beam in the laser beam, and reduce a color cast existing when the user views the external real scene. 
     In an implementation, a center wavelength of the first band is the same as a peak wavelength of the red laser beam, a center wavelength of the second band is the same as a peak wavelength of the green laser beam, and a center wavelength of the third band is the same as a peak wavelength of the blue laser beam, so that the filter can well block light whose wavelength is in the peak wavelengths of the red laser beam, the green laser beam, and the blue laser beam and that is in the laser beam emitted from the outer surface of the combiner. 
     In an implementation, bandwidths of the red laser beam, the green laser beam, and the blue laser beam are between 5 nm and 8 nm, and bandwidths of the first band, the second band, and the third band are between 15 nm and 20 nm, to ensure that the filter can totally block light whose wavelength is in the bands of the red laser beam, the green laser beam, and the blue laser beam and that is in the laser beam emitted from the outer surface of the combiner. 
     In an implementation, the filter includes a red filter coating, a green filter coating, and a blue filter coating that are stacked, the red filter coating is configured to filter the red laser beam, the green filter coating is configured to filter the green laser beam, and the blue filter coating is configured to filter the blue laser beam, to filter the red laser beam, the green laser beam, and the blue laser beam. 
     In an implementation, the augmented reality device includes two augmented reality components, the two augmented reality components are spaced apart on the frame, each augmented reality component includes a combiner, a laser projector, and a filter, and the combiners of the two augmented reality components are disposed side by side. 
     In the augmented reality device shown in this implementation, one augmented reality component corresponds to the left eye of the user, and the other augmented reality component corresponds to the right eye of the user. The two augmented reality components have a same structure, that is, when ensuring the transmittance of the augmented reality device, the two augmented reality components both prevent the laser beam that carries the digital content from being leaked. 
     In an implementation, the frame includes a rim and a leg connected to the rim, the combiners of the two augmented reality components are spaced apart on the rim, and the laser projector is accommodated inside the rim or the leg. 
     In an implementation, the augmented reality device further includes a zoom device, and the zoom device is mounted on the inner surface of the combiner. In other words, the zoom device is located on a side of the combiner that is close to the human eye, to correct eyesight of the user. When the user has an eyesight problem such as nearsightedness, farsightedness, or astigmatism, the zoom device may correct a refractive error of the user when the user views a virtual scene or the external real scene, to improve clarity existing when the user views the virtual scene or the external real scene, and improve user experience of using the augmented reality device. 
     In an implementation, the combiner includes a diffractive optical waveguide, an in-coupling grating, and an out-coupling grating, the in-coupling grating and the out-coupling grating are blazed gratings, the in-coupling grating and the out-coupling grating are spaced apart on an outer surface of the diffractive optical waveguide, and the in-coupling grating is opposite to the laser projector. 
     In another implementation, the in-coupling grating and the out-coupling grating are transmissive gratings, and the in-coupling grating and the out-coupling grating are mounted on an inner surface of the diffractive optical waveguide. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To describe the technical solutions in embodiments of this application or in the background more clearly, the following describes the accompanying drawings for describing embodiments of this application or the background. 
         FIG.  1    is a schematic diagram of a structure of an augmented reality device according to an embodiment of this application; 
         FIG.  2    is a schematic diagram of a structure of wearing the augmented reality device shown in  FIG.  1    on the head of a user; 
         FIG.  3    is a schematic diagram of a simplified structure of the structure shown in  FIG.  2   ; 
         FIG.  4    is a schematic diagram of an enlarged structure of an area A in the structure shown in  FIG.  3    in an embodiment; 
         FIG.  5    is a curve chart of a laser spectrum emitted by a laser projector in an augmented reality device shown in  FIG.  4   ; 
         FIG.  6    is a curve chart of a transmittance curve of a filter and a laser spectrum projected by a laser projector in an augmented reality device shown in  FIG.  4   ; and 
         FIG.  7    is a schematic diagram of an enlarged structure of an area A in the structure shown in  FIG.  3    in another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The following describes embodiments of this application with reference to the accompanying drawings in embodiments of this application. 
       FIG.  1    is a schematic diagram of a structure of an augmented reality device  100  according to an embodiment of this application. 
     The augmented reality device  100  may be an electronic product that combines digital content and a reality scene, for example, AR glasses, an AR helmet, mixed reality (mixrtual reality, MR) glasses, an MR helmet, or the like. That the augmented reality device  100  in the embodiment shown in  FIG.  1    is AR glasses is used as an example for description. 
     In this embodiment, the augmented reality device  100  includes a frame  10  and an augmented reality component  30  mounted on the frame  10 . There are two augmented reality components  30 , and the two augmented reality components  30  are spaced apart on the frame  10 . 
     The frame  10  includes a rim  11  and a leg  12  connected to the rim  11 . There are two legs  12 , and the two legs  12  are connected to two opposite ends of the rim  11 . It should be noted that, in another embodiment, the frame  10  may include a rim  11  and a fixing strap connected to the rim  11 . This is not specifically limited in this application. 
     The rim  11  includes two borders  13  and a bridge  14  connected between the two borders  13 . Each border  13  includes a first border  131  away from the bridge  14  and a second border  132  opposite to the first border  131 . An accommodation cavity is disposed inside the first border  131 , and the accommodation cavity of the first border  131  is configured to accommodate an electronic element of the augmented reality device loft The bridge  14  and the two borders  13  are integrally formed, to simplify a process of forming the rim  11 , and increase overall strength of the rim  11 . A material of the rim  11  includes but is not limited to metal, plastic, resin, or a natural material. It should be understood that the rim  11  is not limited to a full-rim frame shown in  FIG.  1   , or may be a half-rim frame or rimless frame. 
     The two legs  12  are rotatably connected to the two opposite ends of the rim  11 . Specifically, the two legs  12  are rotatably connected to the two borders  13  of the rim  11  respectively. The two legs  12  are respectively connected to the first borders  131  of the two borders  13 . When the augmented reality device  100  is in an unfolded state (as shown in  FIG.  1   ), the two legs  12  rotate relative to the rim  11  to be opposite to each other. In this case, the two legs  12  of the augmented reality device  100  may be respectively mounted on the two ears of a user, and the bridge  14  is mounted on the nose of the user, so that the augmented reality device  100  is worn on the head of the user. When the augmented reality device  100  is in a folded state, the two legs  12  rotate relative to the rim  11  to at least partially overlap each other and be accommodated inside the rim  11 . In this case, the augmented reality device  100  may be stored. It may be understood that, in another embodiment, the two legs  12  may be fixedly connected to the first borders  131  of the two borders  13  respectively, or the two legs  12  and the rim  11  may be integrally formed, that is, the augmented reality device  100  is always in an unfolded state. This is not specifically limited in this application. It should be noted that an accommodation cavity may be also disposed inside the leg  12 , and the accommodation cavity of the leg  12  may also accommodate the electronic element of the augmented reality device  100 . 
     It should be noted that direction words such as “inside” and “outside” that are used when the augmented reality device  100  is mentioned in this application are mainly described based on a direction existing when the augmented reality device  100  is worn by the user on the head. When the augmented reality device  100  is worn by the user, a side close to the head of the user is the inside, and a side away from the head of the user is the outside. This imposes no limitation on a direction of the augmented reality device  100  in another scenario. 
       FIG.  2    is a schematic diagram of a structure of wearing the augmented reality device  100  shown in  FIG.  1    on the head of a user.  FIG.  3    is a schematic diagram of a simplified structure of the structure shown in  FIG.  2   . 
     Next, for ease of description, as shown in  FIG.  2    and  FIG.  3   , a length direction of the augmented reality device  100  is defined as an X-axis direction, a width direction of the augmented reality device  100  is defined as a Y-axis direction, a thickness direction of the augmented reality device  100  is defined as a Z-axis direction, and every two of the X-direction, the Y-direction, and the Z-direction are perpendicular to each other. The X-axis direction is a direction in which one border  13  of the rim  11  faces the other border  13 , and the Z-axis direction is a direction in which the rim  11  faces the leg  12 . 
     In this embodiment, the two augmented reality components  30  have a same structure. Specifically, the two augmented reality components  30  are respectively mounted on the two borders  13  of the rim  11 . When the augmented reality device  100  is worn on the head of the user, one augmented reality component  30  corresponds to the left eye of the user, and the other augmented reality component  30  corresponds to the right eye of the user. In this case, the eyes of the user may view a virtual scene and a real scene by using the two augmented reality components  30 . It should be noted that, in another embodiment, the two augmented reality components  30  may have different structures. This is not specifically limited in this application. 
     Next, for ease of understanding, the augmented reality component  30  corresponding to the right eye of the user is used as an example to specifically describe a structure of the augmented reality component  30 . 
     Referring to  FIG.  3    and  FIG.  4   ,  FIG.  4    is a schematic diagram of an enlarged structure of an area A in the structure shown in  FIG.  3    in an embodiment. 
     The augmented reality component  30  includes a combiner (combiner)  31 , a laser projector  32 , a filter  33 , and a processor  34 . Specifically, the combiner  31  is mounted on the frame  10 . The combiner  31  includes an inner surface  312  and an outer surface  313  that are opposite to each other. The laser projector  32  is mounted on the frame  10 , and is configured to emit a laser beam L o . The laser beam L o  is display light that carries digital content and that is projected by the laser projector  32 . The filter  33  is mounted on the outer surface  313  of the combiner  31 , and a blocking band of the filter  33  includes a band of the laser beam L o . The processor  34  is coupled to the laser projector  32 , to control the laser projector  32  to be turned on and turned off. 
     It should be noted that, in another embodiment, the two augmented reality components  30  may include only one processor  34 , and the processor  34  is coupled to laser projectors  32  of the two augmented reality components  30 , to control the two laser projectors  32  to be turned on and turned off. This is not specifically limited in this application. 
     The combiner  31  is mounted on the rim  11  of the frame  10 . In this embodiment, the combiners  31  of the two augmented reality components  30  are disposed side by side in the X-axis direction. Specifically, the combiners  31  of the two augmented reality components  30  are spaced apart on the rim  11 . The combiner  31  is mounted on the border  13  of the rim  11 . The inner surface  312  of the combiner  31  is a surface of the combiner  31  that faces the inside of the rim  11 . In other words, the outer surface  313  of the combiner  31  is a surface of the combiner  31  that faces the outside of the rim  11 . In this embodiment, the combiner  31  is a device that combines the digital content and the real scene by using a diffractive optical waveguide technology. It should be noted that, in another embodiment, the combiner  31  may be a device that uses a technology such as a bird bath (bird bath), a freeform surface, or a reflection array optical waveguide. 
     Specifically, the combiner  31  includes a diffractive optical waveguide  314 , an in-coupling grating  315 , and an out-coupling grating  316 . The diffractive optical waveguide  314  is mounted on the border  13 . One end of the diffractive optical waveguide  314  is mounted on the first border  131  of the border  13 , and is accommodated in an accommodation cavity  133  of the first border  131 . The other end of the diffractive optical waveguide  314  is mounted on the second border  132  of the border  13 . The diffractive optical waveguide  314  includes an inner surface and an outer surface that are opposite to each other. The inner surface of the diffractive optical waveguide  314  is a surface of the diffractive optical waveguide  314  that faces the inside of the rim  11 . In other words, the outer surface of the diffractive optical waveguide  314  is a surface of the diffractive optical waveguide  314  that faces the outside of the rim  11 . 
     In this embodiment, both the in-coupling grating  315  and the out-coupling grating  316  are blazed gratings. Specifically, the in-coupling  315  is mounted on the outer surface of the diffractive optical waveguide  314 , and is located in the accommodation cavity  133  of the first border  131 . The out-coupling grating  316  is mounted on the outer surface of the diffractive optical waveguide  314 , is spaced apart from the in-coupling grating  315 , and is located between the first border  131  and the second border  132 . It should be understood that the in-coupling grating  315  and the out-coupling grating  316  may be transmissive gratings. In this case, the in-coupling grating  315  and the out-coupling grating  316  are mounted on the inner surface of the diffractive optical waveguide  314 . In addition, the in-coupling grating  315  and the out-coupling grating  316  may be holographic gratings, slanted gratings, polarization gratings, liquid crystal gratings, holographic optical elements, or diffractive optical elements. This is not specifically limited in this application. 
     It should be understood that a grating is an optical device formed by a large quantity of parallel slits with an equal width and an equal distance. When light is incident on a surface of the grating at an angle, the grating can periodically adjust an amplitude or a phase of the light in space, so that the light is emitted from the surface of the grating in a direction different from the angle of incidence. Descriptions of the grating below are understood in a same manner. 
     In this embodiment, the inner surface of the diffractive optical waveguide  314  is the inner surface  312  of the combiner  31 . The inner surface  312  of the combiner  31  includes a light entrance area  3121  and a light exit area  3122 . The light entrance area  3121  of the inner surface  312  is located in the accommodation cavity  133  of the first border  131 . Specifically, the light entrance area  3121  of the inner surface  312  is an area covered by a projection of the in-coupling grating  315  on the inner surface  312 . In other words, an area that is on the inner surface  312  of the combiner  31  and that directly faces the in-coupling grating  315  is the light entrance area  3121  of the inner surface  312 . 
     The light exit area  3122  of the inner surface  312  is spaced apart from the light entrance area  3121 , and is located between the first border  131  and the second border  132 . Specifically, the light exit area  3122  of the inner surface  312  is an area covered by a projection of the out-coupling grating  315  on the inner surface  312 . In other words, an area that is on the inner surface  312  and that directly faces the out-coupling grating  315  is the light exit area  3122  of the inner surface  3123 . 
     The outer surface  313  of the combiner  31  includes a surface of the in-coupling grating  315  that faces away from the diffractive optical waveguide  314 , a surface of the out-coupling grating  316  that faces away from the diffractive optical waveguide  314 , and an area that is on the outer surface of the diffractive optical waveguide  314  and that is not covered by the in-coupling grating  315  and the out-coupling grating  316 . In other words, the outer surface  313  of the combiner  31  includes an outer surface of the in-coupling grating  315 , an outer surface of the out-coupling grating  316 , and the area that is on the outer surface of the diffractive optical waveguide  314  and that is not covered by the in-coupling grating  315  and the out-coupling grating  316 . The outer surface  313  of the combiner  31  includes a light exit area  3131 . Specifically, the light exit area  3131  of the outer surface  313  is a surface of the out-coupling grating  316  that faces away from the diffractive optical waveguide  314 , namely, the outer surface of the out-coupling grating  316 . 
     In this embodiment, the laser projector  32  is located in the accommodation cavity  133  of the first border  131 , and is opposite to the combiner  31 . Specifically, the laser projector  32  is located on a side of the diffractive optical waveguide  314  that faces away from the in-coupling grating  315 . In other words, the laser projector  32  and the in-coupling grating  315  are respectively located on two opposite sides of the diffractive optical waveguide  314 . The laser projector  32  is an image projector that projects a virtual scene by using a laser beam. It may be understood that, when the in-coupling grating  315  is a transmissive grating, the image projector  32  and the in-coupling grating  315  are located on a same side of the diffractive optical waveguide  314 . It should be noted that, in another embodiment, the laser projector  32  may be located in the accommodation cavity of the leg  12  (namely, the inside of the mirror leg  12 ); or the laser projector  32  may be partially located in the accommodation cavity  133  of the first border  131 , and partially located in the accommodation cavity of the leg  12 ; or the laser projector  32  may not be located in the accommodation cavity  133  of the first border  131  or the accommodation cavity of the leg  12 , but is directly exposed to a surface of the border  13 , provided that a line of sight of the user is not blocked when the augmented reality device  100  is used. 
       FIG.  5    is a curve chart of a laser spectrum emitted by a laser projector  32  in an augmented reality device  100  shown in  FIG.  4   . 
     In this embodiment, the laser projector  32  directly faces the light entrance area  3121  of the inner surface  312 , and is configured to project, to the combiner  31 , a laser beam L o  that carries digital content. Specifically, the laser projector  32  includes an optical module, and the optical module includes at least one laser. The optical module of the laser projector  32  includes a red (red, R) laser, a green (green, G) laser, and a blue (blue, B) laser. The laser beam L o  projected by the laser projector  32  includes three types of laser beams, and the three types of laser beams are respectively a red laser beam, a green laser beam, and a blue laser beam. A peak wavelength of the red laser beam is between 630 nm and 640 nm, a peak wavelength of the green laser beam is between 510 nm and 520 nm, a peak wavelength of the blue laser beam is between 445 nm and 455 nm, and band widths of the red laser beam, the green laser beam, and the blue laser beam are between 5 nm and 8 nm. It should be understood that a laser beam is a light source with a narrow bandwidth and high energy, and full widths at half maximum of the red laser beam, the green laser beam, and the blue laser beam are about 1 nm to 2 nm. 
     When the processor  34  turns on the laser projector  32 , that is, when the laser projector  32  is in a turn-on state, the laser projector  32  projects a laser beam L o  to the combiner  31 , a part of the laser beam L o  is emitted from the inner surface  312  of the combiner  31 , and a part of the laser beam L o  is emitted from the outer surface  313  of the combiner  31 . The laser projector  32  projects a laser beam L o  that carries digital content, and the laser beam L o  enters the combiner  31  through the light entrance area  3121  of the inner surface  312 , and is emitted from the light exit area  3122  of the inner surface  312  and the light exit area  3131  of the outer surface  313 . 
     Specifically, the laser beam L o  is vertically emitted to the inner surface of the diffractive optical waveguide  314  (namely, the inner surface  312  of the combiner  31 ), is vertically emitted to the in-coupling grating  315  through the light entrance area  3121  of the inner surface  312 , and is coupled into the diffractive optical waveguide  314  by using the in-coupling grating  315 . The in-coupling grating  315  has adjusted a propagation direction of the laser beam L o  to a state in which a total internal reflection condition is met. The laser beam L o  is totally reflected at least once in the diffractive optical waveguide  314 , and is propagated in a direction of the out-coupling grating  316 , until the laser beam reaches the out-coupling grating  316  and is diffracted. After a part of the laser beam L o  is diffracted, the part of the laser beam L o  is propagated from the light exit area  3122  of the inner surface  312  to the inside of the combiner  31 , that is, is propagated in a direction of the human eye. In the figure, the part of light is marked as incident light L 1  in the eye, and the incident light L 1  may enter the human eye for imaging, so that the user can view the virtual scene that carries the digital content. It may be understood that, because the laser beam L o  includes the red laser beam, the green laser beam, and the blue laser beam, the incident light L 1  in the eye also includes a red laser beam, a green laser beam, and a blue laser beam, the three colors of laser beams may be blended to implement a color display effect. In this case, the virtual scene viewed by the human eye is a color. 
     In addition, after a part of the laser beam L o  is diffracted, the part of the laser beam L o  is propagated from the light exit area  3131  of the outer surface  313  to the outside of the combiner  31 . In the figure, the part of light is marked as leaked light L 2 . It may be understood that, when the processor  34  turns off the laser projector  32 , that is, when the image projector  32  is in a turn-off state, the laser projector  32  does not project the laser beam L o . In this case, no incident light L 1  in the eye enters the human eye for imaging, and no leaked light L 2  is propagated to the outside of the combiner  31 . 
     The filter  33  is located on a side of the combiner  31  that faces away from the laser projector  32 , that is, the filter  33  and the laser projector  32  are located on two opposite sides of the combiner  31 . Specifically, two ends of the filter  33  may be mounted on the outer surface  313  of the combiner  31  by using sealant. There is an air gap between a middle part of the filter  33  and the outer surface  313  of the combiner  31 , so that the laser beam L o  can be totally reflected in the diffractive optical waveguide. A width d of the air gap is about 50 μm. It should be understood that, because thicknesses of the in-coupling grating  315  and the out-coupling grating  316  are at a nanometer level, the filter  33  is not in contact with the in-coupling grating  315  and the out-coupling grating  316 . 
     The filter  33  covers the outer surface  313  of the combiner  31 , to ensure appearance integrity and consistency of the augmented reality device  100 , and improve appearance refinement of the augmented reality device  100 . In other words, the filter  33  covers the outer surface of the in-coupling grating  315 , the outer surface of the out-coupling grating  316 , and the part that is on the outer surface of the diffractive optical waveguide  314  and that is not covered by the in-coupling grating  315  and the out-coupling grating  316 . In this case, the filter  33  may serve as protective glass to protect the in-coupling grating  315  and the out-coupling grating  316 . 
     It should be noted that, in another embodiment, the filter  33  may cover only the light exit area  3131  of the outer surface  313 , that is, the filter  33  may cover only the outer surface of the out-coupling grating  316 . It may be understood that, compared with a manner in which the filter  33  covers only the light exit area  3131  of the outer surface  313 , the filter  33  covers the outer surface  313  of the combiner  31 , so that a difficulty in a process of assembling the filter  33  is reduced, and there is no need to perform additional processing on the filter  33 , to reduce a difficulty in processing the filter  33 , and reduce production costs of the filter  33 . 
     The blocking band of the filter  33  includes the band of the laser beam L o  to block the laser beam L o  emitted from the outer surface  313  of the combiner  31 . It should be understood that the blocking band of the filter  33  means that the filter  33  may block light whose wavelength is in the blocking band, and does not block light whose wavelength is outside the blocking band. In other words, the light whose wavelength is in the blocking band cannot pass through the filter  33  to be propagated, and the light whose wavelength is outside the blocking band can pass through the filter  33  to be normally propagated. In other words, the filter  33  absorbs the light whose wavelength is in the blocking band, and does not absorb the light whose wavelength is outside the blocking band. 
       FIG.  6    is a curve chart of a transmittance curve of a filter  33  and a laser spectrum projected by a laser projector  32  in an augmented reality device  100  shown in  FIG.  4   . 
     In this embodiment, the blocking band of the filter  33  includes bands of the red laser beam, the green laser beam, and the blue laser beam in the laser beam L o , to block light whose wavelength is in the bands of the red laser beam, the green laser beam, and the blue laser beam in the laser beam L o . The filter  33  includes a red filter coating, a green filter coating, and a blue filter coating that are sequentially stacked, and the red filter coating, the green filter coating, and the blue filter coating may be stacked together by using sealant. The red filter coating is configured to block the red laser beam in the laser beam L o , the green filter coating is configured to block the green laser beam in the laser beam L o , and the blue filter coating is configured to block the blue laser beam in the laser beam L o . 
     Specifically, the blocking band of the filter  33  includes three bands, and every two of the three bands of the blocking band are spaced apart. One band of the blocking band includes the band of the red laser beam in the laser beam L o , one band of the blocking band includes the band of the green laser beam in the laser beam L o , and one band of the blocking band includes the band of the blue laser beam in the laser beam L o . Next, for ease of understanding, the three blocking bands are respectively named a first band, a second band, and a third band for description. 
     The first band includes the band of the red laser beam in the laser beam L o , the second band includes the band of the green laser beam in the laser beam L o , and one blocking band includes the band of the blue laser beam in the laser beam L o . A center wavelength of the first band is the same as the peak wavelength of the red laser beam, a center wavelength of the second band is the same as the peak wavelength of the green laser beam, and a center wavelength of the third band is the same as the peak wavelength of the blue laser beam. In other words, the center wavelength of the first band is between 630 nm and 640 nm, the center wavelength of the second band is between 510 nm and 520 nm, and the center wavelength of the third band is between 445 nm and 455 nm, so that the filter can well block light whose wavelength is in the peak wavelengths of the red laser beam, the green laser beam, and the blue laser beam and that is in the laser beam emitted from the outer surface of the combiner. In addition, bandwidths of the first band, the second band, and the third band are between 15 nm and 20 nm, to ensure that the filter  33  can better block the red laser beam, the green laser beam, and the blue laser beam in the laser beam L o . 
     It may be understood that, because the first band, the second band, and the third band are spaced apart, light whose wavelength is between the first band and the second band and light whose wavelength is between the second band and the third band can still pass through the filter  33  to be normally propagated, to reduce an impact caused by the filter  33  on light whose wavelength is among the bands of the red laser beam, the green laser beam, and the blue laser beam in the laser beam L o , and reduce a color cast existing when the user views the external real scene. In addition, the bandwidths of the first band, the second band, and the third band are only between 15 nm and 20 nm, that is, the bandwidths of the first band, the second band, and the third band are small. Therefore, most of ambient light can pass through the filter  33  to be normally propagated. This also further reduces the color cast existing when the user views the external real scene. 
     In this embodiment, the processor  34  is located in the accommodation cavity  133  of the first border  131 , and is connected to the laser projector  32 . The processor  34  may include one or more processing units. The plurality of processing units may be, for example, an application processor (application processor, AP), a modem processor, a graphics processing unit (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a controller, a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, and/or a neural-network processing unit (neural-network processing unit, NPU). Different processing units may be independent devices, or may be integrated into one or more processors. It should be understood that the processor  34  may be a central processing unit (central processing unit, CPU) of the augmented reality device  100 , or may be another processor of the augmented reality device  100 . 
     When the processor  34  turns on the laser projector  32 , that is, when the laser projector  32  is in a turn-on state, the filter  33  blocks the laser beam L o  emitted from the outer surface  313  of the combiner  31 . Specifically, after the laser beam L o  projected by the laser projector  32  enters the combiner  31  through the light entrance area  3121  of the inner surface  312 , the incident light L 1  is emitted from the light exit area  3121  of the inner surface  312  into the human eye for imaging, and the leaked light L 2  is emitted from the light exit area  3131  of the outer surface  313  to the filter  33 . Because the blocking band of the filter  33  includes the band of the laser beam L o , the filter  33  blocks the leaked light L 2 . This is equivalent to absorbing the leaked light L 2  by the filter  33 , to prevent the leaked light L 2  emitted from the outer surface  313  of the combiner  31  from passing through the active filter  33  and being emitted into an external environment, and prevent the leaked light L 2  that carries the digital content from being leaked. This may improve privacy of the user and sociality of the augmented reality device  100 , and may further prevent the leaked light L 2  that is leaked from forming a small display window on a surface of the augmented reality device  100 , to improve appearance refinement existing when the user uses the augmented reality device  100 . 
     In addition, after passing through the filter  33 , ambient light L c  whose wavelength is outside the blocking band enters the combiner  31  through the outer surface  313  of the combiner  31 , and is emitted from the inner surface  312  of the combiner  31 . Because the blocking band of the filter  33  is narrow, most of the ambient light L c  may pass through the filter  33  to enter the combiner  31 , and is propagated from the inner surface  312  of the combiner  31  to the direction of the human eye, to enter the human eye for imaging. In other words, the human eye may view the external real scene through the filter  33  and the combiner  31 . 
     In addition, when the processor  34  turns off the laser projector  32 , that is, when the laser projector  32  is in a turn-off state, the laser projector  32  does not project the laser beam L o  that carries the digital content, so that no incident light L 1  in the eye is incident to the human eye, no leaked light L 2  is leaked out of the augmented reality device  100 , and only the ambient light L c  whose wavelength is outside the blocking band enters the human eye. In other words, the human eye can only view the external real scene. 
     In the augmented reality device  100  shown in this embodiment, the laser projector  32  is used to emit the red laser beam, the green laser beam, and the blue laser beam that have narrow bands, and the filter  33  whose blocking band includes the bands of the red laser beam, the green laser beam, and the blue laser beam is mounted on the outer surface  313  of the combiner  31 , so that the laser beam leaked from the combiner  31  can be blocked when the transmittance of the augmented reality device  100  is ensured. This improves privacy and sociality of the augmented reality device  100 , and further improves appearance refinement existing when the user uses the augmented reality device  100 . 
     It may be understood that, in another embodiment, when the laser projector  32  emits only one color of laser beam such as the red laser beam, the filter whose blocking band includes only the band of the red laser beam may be mounted on the outer surface of the combiner  31 . This is not specifically limited in this application. 
       FIG.  7    is a schematic diagram of an enlarged structure of an area A in the structure shown in  FIG.  3    in another embodiment. 
     A difference between the augmented reality device  100  shown in this embodiment and the foregoing first augmented reality device  100  lies in that the augmented reality device  100  further includes a zoom device  50 . The zoom device  50  is mounted on the inner surface  312  of the combiner  31 , and covers the inner surface  312  of the combiner  31 . In other words, the zoom device  50  is located on a side of the combiner  31  that is close to the human eye, to correct eyesight of the user. When the user has an eyesight problem such as nearsightedness, farsightedness, or astigmatism, the zoom device  50  may correct a refractive error of the user when the user views the virtual scene that carries the digital content or the external real scene, to improve clarity existing when the user views the virtual scene or the external real scene, and improve user experience of using the augmented reality device  100 . The zoom device  50  may be a device that can implement zooming, for example, a liquid crystal lens, a liquid lens, an Alvarez lens, or a mechanical zoom lens. It should be understood that the zoom device  50  may be an optical device with fixed focal power, for example, a lens with a degree, or may be an optical device that has adjustable focal power and that is coupled to the processor  34 . When using the augmented reality device  100 , the user may adjust focal power of the zoom device  50  based on a diopter of the user, so that the focal power matches the eyesight of the user, to improve adaptability of the augmented reality device  100 , and improve use flexibility of the augmented reality device  100 . 
     The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.