Diffraction waveguide module and near-to-eye display equipment

Abstract

The invention provides a diffraction waveguide module, which comprises an optical waveguide layer and a grating structure, the optical waveguide layer comprises a first optical waveguide layer and a second optical waveguide layer, the first optical waveguide layer and the second optical waveguide layer are stacked at an interval, the first optical waveguide layer comprises a first surface facing the second optical waveguide layer, and the grating structure comprises a second surface facing the second optical waveguide layer. The second optical waveguide layer comprises a second surface facing the first optical waveguide layer; the grating structure comprises a first grating structure and a second grating structure, the first grating structure is arranged on the first surface, and the second grating structure is arranged on the second surface. The grating structure of the diffraction waveguide module is arranged between the first optical waveguide layer and the second optical waveguide layer, so that the grating structure is prevented from being damaged due to collision; moreover, the manufacturing cost is saved, the thickness of the diffraction waveguide module is reduced, and the weight of the diffraction waveguide module is reduced. The invention further provides the near-to-eye display equipment provided with the diffraction waveguide module.

Description

Technical Field

[0001] The present application relates to the technical field of diffractive optical devices, and in particular to a diffractive waveguide module and a near-eye display device provided with the diffractive waveguide module. Background Art

[0002] With the development of technology, augmented reality (AR) display devices, such as AR glasses, can see both the real world outside and virtual images. Near-eye display devices usually include a diffraction waveguide module and a micro-projector. The diffraction waveguide module can transmit the light projected by the micro-projector to the front of the user's eyes, so as to superimpose a virtual image on the real image in front of the user's eyes, that is, it has the function of augmented reality. The existing AR optical waveguide is generally realized by a diffraction optical waveguide based on a surface relief grating, that is, the diffraction waveguide module usually includes an optical waveguide layer and a surface relief grating arranged on the waveguide, wherein a part of the surface relief grating forms an in-coupling grating on the optical waveguide layer, and another part of the surface relief grating forms an out-coupling grating on the optical waveguide layer. The light of the display image generated by the micro-projector enters the optical waveguide layer through the in-coupling grating, is transmitted by the optical waveguide layer, and then is coupled out through the out-coupling grating and emitted into the user's eyes. Since the surface relief grating is a relatively fragile micro-nano structure, it is necessary to add a light-transmitting cover plate on the surface relief grating to protect the surface relief grating. The cover plate and the optical waveguide layer are generally bonded together by frame glue to form the diffraction waveguide module. The diffraction waveguide module can meet the requirements of a normal augmented reality display device and has good reliability.

[0003] However, the existing diffraction waveguide module includes not only an optical waveguide layer but also a cover plate, which makes the diffraction waveguide module thicker and heavier. In particular, when the augmented reality display device uses a double-layer optical waveguide layer plus a cover plate, the diffraction waveguide module at this time includes two layers of optical waveguide layers and at least one cover plate, which makes the diffraction waveguide module thicker and heavier. Summary of the invention

[0004] A first aspect of the present application provides a diffractive waveguide module, the diffractive waveguide module comprising:

[0005] an optical waveguide layer, the optical waveguide layer comprising a first optical waveguide layer and a second optical waveguide layer, the first optical waveguide layer and the second optical waveguide layer being stacked with an interval, the first optical waveguide layer comprising a first surface facing the second optical waveguide layer, and the second optical waveguide layer comprising a second surface facing the first optical waveguide layer; and

[0006] The grating structure includes a first grating structure and a second grating structure. The first grating structure is arranged on the first surface, and the second grating structure is arranged on the second surface.

[0007] The second aspect of the present application further provides a near-eye display device, the near-eye display device comprising the diffraction waveguide module and the image source as described in the first aspect, the diffraction waveguide module comprising an optical waveguide layer and a grating structure, the optical waveguide layer comprising a first optical waveguide layer and a second optical waveguide layer, the first optical waveguide layer and the second optical waveguide layer being stacked at intervals, the first optical waveguide layer comprising a first surface facing the second optical waveguide layer, and the second optical waveguide layer comprising a second surface facing the first optical waveguide layer; the grating structure comprising a first grating structure and a second grating structure, the first grating structure being arranged on the first surface, and the second grating structure being arranged on the second surface; the image source is located on a side of the first optical waveguide layer facing away from the second optical waveguide layer.

[0008] The first grating structure and the second grating structure of the grating structure of the present application are respectively arranged on the first surface of the first optical waveguide layer facing the second optical waveguide layer and the second surface of the second optical waveguide layer facing the first optical waveguide layer, that is, the first grating structure and the second grating structure are respectively located on the inner surfaces of the first optical waveguide layer and the second optical waveguide layer, which can prevent the first grating structure and the second grating structure from being damaged by collision, and the diffraction waveguide module omits the cover plate, saving the manufacturing cost, reducing the thickness of the diffraction waveguide module and reducing the weight of the diffraction waveguide module. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of a diffraction waveguide module provided in one embodiment of the present application.

[0010] Figure 2 Schematic diagram of light propagation in a reflective light waveguide provided with a reflective grating.

[0011] Figure 3 Schematic diagram of light propagation in a transmission light waveguide with a transmission grating.

[0012] Figure 4 It is a schematic diagram of light propagation in a double-layer reflective light waveguide with a reflective grating.

[0013] Figure 5 Schematic diagram of light propagation in a double-layer transmission light waveguide with a transmission grating.

[0014] Figure 6 yes Figure 1 Schematic diagram of light propagation in the diffractive waveguide module.

[0015] Figure 7 yes Figure 1A schematic diagram of a diffraction waveguide module in a near-eye display device provided in one embodiment.

[0016] Figure 8 yes Figure 1 A schematic diagram of a near-eye display device provided in another embodiment using the diffraction waveguide module in FIG.

[0017] Fig. 9 yes Figure 1 A schematic diagram of a near-eye display device provided in another embodiment using the diffraction waveguide module in FIG.

[0018] Fig.10 yes Figure 1 A schematic diagram of a near-eye display device provided in another embodiment using the diffraction waveguide module in FIG.

[0019] Fig.11 It is a schematic structural diagram of a diffraction waveguide module provided in another embodiment of the present application.

[0020] Fig.12 yes Fig.11 Schematic diagram of light propagation in the diffractive waveguide module.

[0021] Main markings:

[0022] 100, diffraction waveguide module; 20, first optical waveguide layer; 22, first surface; 25, first grating structure; 252, first coupling-in region; 254, first coupling-out region; 26, reflective film; 300, first near-eye display device; 30, reflective optical waveguide; 32, image source; 34, optical waveguide layer; 36, reflective grating; 362, third coupling-in region; 364, third coupling-out region; 40, second optical waveguide layer; 42, second surface; 45, A second grating structure; 452, a second coupling-in region; 454, a second coupling-out region; 500, a second near-eye display device; 50, a transmission light waveguide; 56, a transmission grating; 562, a fourth coupling-in region; 564, a fourth coupling-out region; 600, a third near-eye display device; 700, a fourth near-eye display device; 800, a fifth near-eye display device; 810, a wearing frame; 812, a wearing frame; 814, a window area; 900, a sixth near-eye display device. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] It should be noted that the reference to "embodiment" or "implementation method" in this document means that the specific features, structures or characteristics described in conjunction with the embodiment or implementation method may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] The terms "first" and "second" appearing in this application are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" refers to two or more, unless otherwise clearly and specifically defined.

[0026] See also Figure 1 One embodiment of the present application provides a diffraction waveguide module 100 that can be used in a near-eye display device, which can be but is not limited to AR glasses and other devices. The diffraction waveguide module 100 is described in detail below. The diffraction waveguide module 100 includes an optical waveguide layer and a grating structure, the optical waveguide layer includes a first optical waveguide layer 20 and a second optical waveguide layer 40, the first optical waveguide layer 20 and the second optical waveguide layer 40 are stacked at intervals, the first optical waveguide layer 20 includes a first surface 22 facing the second optical waveguide layer 40, and the second optical waveguide layer 40 includes a second surface 42 facing the first optical waveguide layer 20; the grating structure includes a first grating structure 25 and a second grating structure 45, the first grating structure 25 is arranged on the first surface 22, and the second grating structure 45 is arranged on the second surface 42. Optionally, the first grating structure 25 is opposite to the second grating structure 45, and the first grating structure 25 and the second grating structure 45 are located between the first optical waveguide layer 20 and the second optical waveguide layer 40, that is, the first grating structure 25 and the second grating structure 45 are located on the inner surfaces of the first optical waveguide layer 20 and the second optical waveguide layer 40, respectively.

[0027] Optionally, the grating structure includes a plurality of grating units, and the plurality of grating units have a first period in a first direction and a second period in a second direction different from the first direction. Specifically, the first period includes a first direction and a first modal length extending along the first direction, and the second period includes a second direction and a second modal length extending along the second direction; by adjusting the direction of the first direction of the grating structure and the size of the first modal length, and / or the direction of the second direction and the size of the second modal length. The grating unit may be one or a combination of, but not limited to, an elliptical cylindrical structure, a conical structure, a pyramidal structure, a quasi-prism structure, and a truncated cone structure. The grating unit may also be an irregular shape or a combination of irregular shapes; therefore, the shape of the grating unit may be designed according to the desired diffraction energy distribution.

[0028] The surface of the first optical waveguide layer 20 of the diffractive waveguide module 100 of the present application facing the second optical waveguide layer 40 is provided with a first grating structure 25, and the surface of the second optical waveguide layer 40 facing the first optical waveguide layer 20 is provided with a second grating structure 45. Therefore, the grating structure of the diffractive waveguide module 100 of the present application is located between the first optical waveguide layer 20 and the second optical waveguide layer 40, the first grating structure 25 and the second grating structure 45 are arranged opposite to each other, and the first grating structure 25 and the second grating structure 45 are placed inwardly and are not easily collided. That is, the grating structure of the diffractive waveguide module 100 does not need to be protected by an additional cover plate, that is, the first grating structure 25 and the second grating structure 45 can be protected without a cover plate. Compared with the diffractive waveguide module in the prior art, the diffractive waveguide module 100 of the present application omits the cover plate, which not only saves the manufacturing cost, but also reduces the thickness of the diffractive waveguide module 100 and the weight of the diffractive waveguide module 100.

[0029] Optionally, the first grating structure 25 includes a first coupling-in region 252 and a first coupling-out region 254, and the second grating structure 45 includes a second coupling-in region 452 and a second coupling-out region 454. The first coupling-in region 252 and the second coupling-in region 452 are located on one side of the diffractive waveguide module 100, and the first coupling-out region 254 and the second coupling-out region 454 are located on the other side of the diffractive waveguide module 100. Specifically, the first coupling-in region 252 is disposed on one side of the first surface 22 of the first optical waveguide layer 20, and the first coupling-out region 254 is disposed on the other side of the first surface 22 of the first optical waveguide layer 20; the second coupling-in region 452 is disposed on one side of the second surface 42 of the second optical waveguide layer 40, and the second coupling-out region 454 is disposed on the other side of the second surface 42 of the second optical waveguide layer 40; the first coupling-out region 254 and the second coupling-in region 452 are on the same side, and the first coupling-out region 254 and the second coupling-out region 454 are on the same side. Specifically, the plurality of grating units on the first surface 22 of the first optical waveguide layer 20 may be arranged to form a first coupling-in region 252 and a first coupling-out region 254, wherein the first coupling-in region 252 is used to couple light into the first optical waveguide layer 20, and the first coupling-out region 254 is used to receive light after total reflection from the first optical waveguide layer 20, and couple the light out of the first optical waveguide layer 20 through the first coupling-out region 254; the plurality of grating units on the second surface 42 of the second optical waveguide layer 40 may be arranged to form a second coupling-in region 452 and a second coupling-out region 454, wherein the second coupling-in region 452 is used to couple light into the second optical waveguide layer 40, and the second coupling-out region 454 is used to receive light after total reflection from the second optical waveguide layer 40, and couple the light out of the second optical waveguide layer 40 through the second coupling-out region 454.

[0030] When the diffraction waveguide module 100 is used, the light of the display image generated by the image source enters the first optical waveguide layer 20 and the second optical waveguide layer 40 respectively through the first coupling-in region 252 and the second coupling-in region 452, and is emitted to the first coupling-out region 254 after being totally reflected by the first optical waveguide layer 20, and is totally reflected by the second optical waveguide layer 40 to the second coupling-out region 454, and then is coupled out by the first coupling-out region 254 and the second coupling-out region 454 to be emitted to the user's eyes.

[0031] The so-called optical waveguide layer is a medium device that guides the propagation of light waves therein. The optical waveguide layer is also called an optical waveguide layer, a dielectric waveguide layer or an optical waveguide layer. The optical waveguide layer usually includes two categories: one is an integrated optical waveguide layer, including a planar (thin film) dielectric waveguide layer and a strip dielectric waveguide layer, which are usually part of an optoelectronic integrated device (or system), so they are called integrated optical waveguide layers; the other is a cylindrical waveguide layer, usually called an optical fiber (optical fiber). Usually, the optical waveguide layer is a guiding structure for transmitting light (optical frequency electromagnetic waves) composed of an optically transparent medium (such as quartz glass). When the light is transmitted in the optical waveguide layer, total reflection will occur in the optical waveguide layer, so that the light is confined to propagate in the optical waveguide layer. As the main technical solution for augmented reality AR glasses at present, the optical waveguide layer can transmit the light projected by the micro projector to the front of the glasses, and superimpose a virtual image on the real image in front of the user's eyes, that is, it has the function of augmented reality.

[0032] Optionally, the optical waveguide layer is a light-transmitting material, and the optical waveguide layer may be, but is not limited to, glass, resin, etc. Specifically, the first optical waveguide layer 20 and the second optical waveguide layer 40 may be, but are not limited to, glass, resin, etc. Optionally, the resin material may be, but is not limited to, an ultraviolet curable resin material or a thermal curable resin material, etc., and the grating structure may be formed on the optical waveguide layer by ultraviolet curing or thermal curing.

[0033] Total reflection means that there is no loss or leakage in the transmission process of light. "Total reflection" is required so that light can be reflected back and forth in the optical waveguide layer in a wave shape without being transmitted out. Total reflection requires two conditions to be met: (1) the transmission medium, i.e., the optical waveguide layer, needs to have a higher refractive index than the surrounding medium; (2) the incident angle of light entering the optical waveguide layer needs to be greater than the critical angle.

[0034] The so-called coupling-in area has a diffraction grating, that is, the coupling-in area has a surface relief grating, and the so-called coupling-out area has a diffraction grating, that is, the coupling-out area has a surface relief grating; light is emitted from an image source such as a projection light machine, coupled in through the coupling-in area, and is transmitted to the coupling-out area through total reflection in the optical waveguide layer to form an image.

[0035] The optical waveguide layer with a diffraction grating on the surface is generally divided into a reflective array optical waveguide and a diffraction optical waveguide, and the diffraction optical waveguide can be further divided into a surface relief grating and a volume holographic grating. The surface relief grating (i.e., diffraction grating) is a relatively popular technical solution at present, that is, the morphology of the coupling-in area and the coupling-out area is a surface relief grating, and the surface relief grating has a light diffraction function. Optionally, the surface relief grating can be manufactured by nanoimprinting technology at present. Specifically, a mold is made in advance, and then the mold is imprinted on a film layer coated with an imprinting glue (similar to stamping), that is, the structure can be transferred to the imprinting glue to form a surface relief grating. Optionally, the surface relief grating can also be a micro-nano structure formed by nanoimprinting, and the surface relief grating can also be a micro-nano structure formed by etching the substrate.

[0036] The so-called augmented reality (AR) means that the light to be displayed generated by the image source in the near-eye display device enters the optical waveguide layer through the coupling-in grating, and is then coupled out through the coupling-out grating and emitted to the human eye; the external environment light (for example, outdoor sunlight, light generated by indoor lighting) can also pass through the coupling-in grating to enter the human eye. Therefore, the user can view the image in the image source and the image in the external environment, thereby realizing the augmented reality function that combines virtual and real.

[0037] like Figure 2 As shown, Figure 2 3 is a schematic diagram of light propagation of a first near-eye display device 300 having a reflective light waveguide 30 provided with a reflective grating 36. The first near-eye display device 300 includes a reflective light waveguide 30 and an image source 32. The reflective light waveguide 30 includes a light waveguide layer 34 and a reflective grating 36. The image source 32 is a device for generating an original image. The image source 32 may be, but is not limited to, a micro-projector, a Micro-LED display screen, etc. The image source 32 is disposed on one side of the light waveguide layer 34. The reflective grating 36 is disposed on a surface of the light waveguide layer 34 away from the image source 32. The reflective grating 36 includes a third coupling-in region 362 and a third coupling-out region 364. The third coupling-in region 362 faces the image source 32, and the third coupling-out region 364 faces the user's eye 37.

[0038] When the first near-eye display device 300 is used, the light of the display image generated by the image source 32 enters the optical waveguide layer 34 through the third coupling-in region 362, is emitted to the third coupling-out region 364 after total reflection by the optical waveguide layer 34, and then is coupled out by the third coupling-out region 364 and emitted to the user's eyes.

[0039] Optionally, the first near-eye display device 300 further includes a cover plate, which covers the reflective grating 36 , that is, the cover plate covers the side of the optical waveguide layer 34 where the reflective grating 36 is provided, and the cover plate is used to protect the reflective grating 36 .

[0040] like Figure 3 As shown, Figure 3 Schematic diagram of light propagation of a second near-eye display device 500 having a transmission light waveguide 50 provided with a transmission grating 56. The second near-eye display device 500 comprises a transmission light waveguide 50 and an image source 32, wherein the transmission light waveguide 50 comprises a light waveguide layer 34 and a transmission grating 56, wherein the image source 32 is disposed on one side of the light waveguide layer 34, and the transmission grating 56 is disposed on a surface of the light waveguide layer 34 facing the image source 32; the transmission grating 56 comprises a fourth coupling-in region 562 and a fourth coupling-out region 564, wherein the fourth coupling-in region 562 faces the image source 32, and the fourth coupling-out region 564 faces the user's eye 37.

[0041] When the second near-eye display device 500 is used, the light of the display image generated by the image source 32 enters the optical waveguide layer 34 through the fourth coupling-in region 562, is emitted to the fourth coupling-out region 564 after total reflection by the optical waveguide layer 34, and then is coupled out by the fourth coupling-out region 564 and emitted to the user's eyes.

[0042] Optionally, the second near-eye display device 500 further includes a cover plate, which covers the transmission grating 56 , that is, the cover plate covers the side of the optical waveguide layer 34 where the transmission grating 56 is provided, and the cover plate is used to protect the transmission grating 56 .

[0043] like Figure 4 As shown, Figure 4 3 is a schematic diagram of light propagation of a double-layer reflective light waveguide 30 provided with a reflective grating 36. The third near-eye display device 600 includes two reflective light waveguides 30 and an image source 32. The two reflective light waveguides 30 are stacked with each other. The reflective light waveguide 30 includes a light waveguide layer 34 and a reflective grating 36. The image source 32 is located on a side of the light waveguide layer 34 away from the reflective grating 36. The reflective grating 36 is provided on a surface of the light waveguide layer 34 away from the image source 32. The reflective grating 36 includes a third coupling-in region 362 and a third coupling-out region 364. The third coupling-in region 362 faces the image source 32, and the third coupling-out region 364 faces the user's eye 37.

[0044] When the third near-eye display device 600 is used, the light of the display image generated by the image source 32 enters the two optical waveguide layers 34 through the two third coupling-in regions 362 respectively, is emitted to the two third coupling-out regions 364 after being totally reflected by the two optical waveguide layers 34, and then is coupled out by the two third coupling-out regions 364 and emitted to the user's eyes 37.

[0045] Optionally, the third near-eye display device 600 further includes a cover plate, which covers the reflective grating 36 away from the image source 32 , that is, the cover plate covers the reflective grating 36 of the optical waveguide layer 34 away from the image source 32 , and the cover plate is used to protect the reflective grating 36 .

[0046] like Figure 5 As shown, Figure 5 Schematic diagram of light propagation of a fourth near-eye display device 700 having a double-layer transmission light waveguide 50 with a transmission grating 56. The fourth near-eye display device 700 includes two transmission light waveguides 50 and an image source 32. The two transmission light waveguides 50 are stacked with each other. The transmission light waveguide 50 includes a light waveguide layer 34 and a transmission grating 56. The image source 32 is located on a side of the light waveguide layer 34 facing the transmission grating 56. The transmission grating 56 is located on a surface of the light waveguide layer 34 facing the image source 32. The transmission grating 56 includes a fourth coupling-in region 562 and a fourth coupling-out region 564. The fourth coupling-in region 562 faces the image source 32, and the fourth coupling-out region 564 faces the user's eye 37.

[0047] When the fourth near-eye display device 700 is used, the light of the display image generated by the image source 32 enters the two optical waveguide layers 34 through the two fourth outcoupling areas 564 respectively, is emitted to the two fourth outcoupling areas 564 after total reflection by the two optical waveguide layers 34, and then is coupled out by the two fourth outcoupling areas 564 to be emitted to the user's eyes 37.

[0048] Optionally, the fourth near-eye display device 700 further includes a cover plate, which covers the transmission grating 56 near the image source 32 , that is, the cover plate covers the transmission grating 56 of the optical waveguide layer 34 near the image source 32 , and the cover plate is used to protect the transmission grating 56 .

[0049] Please also read Figure 1 and Figure 6 As shown, the present application provides a fifth near-eye display device 800 further including an image source 32, which is located on the side of the first light waveguide layer 20 away from the second light waveguide layer 40, and the image source 32 is directly opposite to the first coupling-in region 252 and the second coupling-out region 454. When the fifth near-eye display device 800 is used, the light of the display image generated by the image source 32 enters the first light waveguide layer 20 and the second light waveguide layer 40 through the first coupling-in region 252 and the second coupling-in region 452, respectively, and is emitted to the first coupling-out region 254 and the second coupling-out region 454 after being totally reflected by the first light waveguide layer 20, respectively, and then is coupled out by the first coupling-out region 254 and the second coupling-out region 454 to be emitted to the user's eyes.

[0050] Optionally, the first grating structure 25 is a reflection grating, and the second grating structure 45 is a transmission grating. Specifically, the reflection grating forms a first coupling-in region 252 at the first surface 22 facing the image source 32, and the reflection grating forms a first coupling-out region 254 at a side of the first surface 22 away from the image source 32; the transmission grating forms a second coupling-in region 452 at the second surface 42 facing the image source 32, and the transmission grating forms a second coupling-out region 454 at a side of the second surface 42 away from the image source 32.

[0051] Optionally, there is an air gap between the first optical waveguide layer 20 and the second optical waveguide layer 40 .

[0052] Optionally, the first coupling region 252 and the second coupling region 452 can be but are not limited to blazed gratings, straight tooth gratings or helical tooth gratings; the first coupling region 254 and the second coupling region 454 can be but are not limited to blazed gratings, straight tooth gratings or helical tooth gratings.

[0053] Optionally, the period of the grating structure ranges from 200nm to 600nm. Preferably, the period value of the grating structure is 300nm, 360nm or 400nm; the duty cycle of the grating structure ranges from 0.01 to 0.99, preferably, the duty cycle of the grating structure is 0.4, 0.5 or 0.6. Specifically, the period of the first grating structure 25 ranges from 200nm to 600nm, preferably, the period value of the first grating structure 25 is 300nm, 360nm or 400nm; the duty cycle of the first grating structure 25 ranges from 0.01 to 0.99, preferably, the duty cycle of the first grating structure 25 is 0.4, 0.5 or 0.6. The period range of the second grating structure 45 is 200nm-600nm, preferably, the period value of the second grating structure 45 is 300nm, 360nm or 400nm; the duty cycle range of the second grating structure 45 is 0.01-0.99, preferably, the duty cycle of the second grating structure 45 is 0.4, 0.5 or 0.6.

[0054] Optionally, the depth of the grating structure ranges from 10nm to 300nm. Preferably, the depth of the grating structure is 50nm, 80nm or 100nm. Specifically, the depth of the first grating structure 25 ranges from 10nm to 300nm, preferably, the depth of the first grating structure 25 is 50nm, 80nm or 100nm; the depth of the second grating structure 45 ranges from 10nm to 300nm, preferably, the depth of the second grating structure 45 is 50nm, 80nm or 100nm.

[0055] Please also read Figure 6 and Figure 7 , Figure 7 FIG. 1 is a schematic diagram of a near-eye display device 800a provided in one embodiment in which the diffractive waveguide module 100 of the present application is applied. The near-eye display device 800a includes the diffractive waveguide module 100 provided in the previous embodiment.

[0056] Specifically, the near-eye display device 800a further includes a wearing frame 810 and a wearing frame 812. The wearing frame 810 has two window areas 814 spaced apart, and at least one of the two window areas 814 is provided with the diffraction waveguide module 100 as described above. That is, at least one window area 814 is provided with a first optical waveguide layer 20 and a first coupling-in area 252 and a first coupling-out area 254 thereon, and a second optical waveguide 40 and a second coupling-in area 452 and a second coupling-out area 454 thereon, and the one window area 814 can make the human eye see the virtual image, and the first coupling-in area 252 and the second coupling-in area 452 themselves can transmit ambient light, so that the one window area 814 can achieve the effect of augmented reality. In the schematic diagram of this embodiment, the two window areas 814 are both provided with a diffractive waveguide module 100 as an example for illustration, and each first coupling region 252 and second coupling region 452 are located on one side of the corresponding first grating structure 25 and second grating structure 45 .

[0057] Please also read Figure 6 and Figure 8 , Figure 8 A schematic diagram of a near-eye display device 800b provided for another embodiment of the present application. The near-eye display device 800b includes a wearing frame 810, a wearing frame 812, an image source 32 and a diffraction waveguide module 100, and the wearing frame 812 is connected to the wearing frame 810. The image source 32 is arranged on one side of the first optical waveguide layer 20 and the second optical waveguide layer 40, and is used to generate light according to the image to be displayed. The image source 32 is close to the first coupling region 252 and the second coupling region 452, and the image source 32 is used to input light into the first coupling region 252 and the second coupling region 452 according to a preset rule. Specifically, the image source 32 is arranged at the connection between the wearing frame 810 and the wearing frame 812. Each first coupling region 252 and second coupling region 452 is located on one side of the corresponding first grating structure 25 and second grating structure 45, i.e., side projection mode; preferably, the first coupling region 252 and second coupling region 452 are located in the middle of one side of the corresponding first decoupling region 254 and second decoupling region 454.

[0058] Specifically, the near-eye display device 800b is an AR pair of glasses, and the wearing frame 812 is also called a glasses leg.

[0059] When the near-eye display device is an AR glasses, in order to make the optical waveguide layer structure composed of the first optical waveguide layer 20, the first coupling region 252, the first coupling region 254 and the second optical waveguide layer 40, the second coupling region 452 and the second coupling region 454 fit the shape of the glasses as much as possible, the first coupling region 252 and the second coupling region 452 can be arranged near the connection between the wearing frame 810 and the wearing frame 812. A side projection layout is adopted, and the image source 32 is placed at the connection between the wearing frame 810 and the wearing frame 812, and the first coupling region 252 and the second coupling region 452 are arranged on one side of the window area 814 close to the image source 32. When the near-eye display device has two window areas 814, the two diffractive waveguide modules 100 are respectively located in the two window areas 814, and the two first coupling regions 252 and the second coupling regions 452 are respectively located on opposite sides of the two window areas 814. When the AR glasses are worn, the two first coupling-in regions 252 and the second coupling-in region 452 are located on opposite sides of the human eye, and the two first coupling-out regions 254 and the second coupling-out regions 454 are respectively facing the user's eyes.

[0060] Please also read Figure 6 and Fig. 9 , Fig. 9 800c is a schematic diagram of a near-eye display device 800c provided in another embodiment of the present application. The structure of the near-eye display device 800c of this embodiment is similar to the structure of the near-eye display device 800 described above, except that: the first coupling region 252 and the second coupling region 452 in each window area 814 are located on the top side of the first coupling region 254 and the second coupling region 454, that is, the first coupling region 252 and the second coupling region 452 are arranged in a top projection mode; preferably, the first coupling region 252 and the second coupling region 452 are located in the middle of the top side of the first coupling region 254 and the second coupling region 454.

[0061] Please also read Figure 6 and Fig.10 , Fig.10 800d is a schematic diagram of a near-eye display device 800d provided in another embodiment of the present application. The structure of the near-eye display device 800d of this embodiment is similar to that of the near-eye display device 800c, except that: the two image sources 32 of the near-eye display device 800d are respectively arranged at the connection between the wearing frame 810 and the wearing frame 812, and the two image sources 32 are used to input light into the adjacent first coupling area 252 and the second coupling area 452.

[0062] In other embodiments, the near-eye display device further includes a camera, an environmental sensor, a processor and a battery. The image source 32, the camera and the environmental sensor are all electrically connected to the processor and are used to work under the control of the processor. The camera is used to collect video data, and the environmental sensor is used to detect the surrounding environment. The battery is used to power the image source 32, the camera, the environmental sensor and the processor.

[0063] See also Fig.11 The structure of a diffraction waveguide module 100a provided in another embodiment of the present application is similar to the structure of the diffraction waveguide module 100 provided in the above embodiment, except that: the diffraction waveguide module 100a replaces the second optical waveguide layer 40 in the diffraction waveguide module 100 with a first optical waveguide layer 20, and adds a reflective film 26; that is, the diffraction waveguide module 100a includes two first optical waveguide layers 20 stacked at intervals, wherein a first optical waveguide layer 20 is provided with a first grating structure 25 on a surface facing the other first optical waveguide layer 20, and another first optical waveguide layer 20 is provided with a first grating structure 25 on a surface facing the one of the first optical waveguide layers 20; the two first grating structures 25 are provided on the inner surfaces of the two first optical waveguide layers 20, so as to prevent the first grating structures 25 from being damaged by collision. The first grating structure 25 includes a first coupling-in region 252 located on one side of the first optical waveguide layer 20 and a first coupling-out region 254 located on the other side of the first optical waveguide layer 20, the two first coupling-in regions 252 are located on the same side of the first optical waveguide layer 20, and the two first coupling-out regions 254 are located on the other side of the first optical waveguide layer 20. The diffractive waveguide module 100a further includes a reflective film 26, which is stacked on the surface of the optical waveguide layer away from the grating structure; specifically, the reflective film 26 is stacked on the surface of one of the first optical waveguide layers 20 away from the first grating structure 25. Optionally, the reflective film 26 is directly opposite to the first coupling-in region 252.

[0064] Optionally, the reflective film 26 may be made of but not limited to a metal reflective film layer or a coating layer, wherein the metal reflective film layer includes but is not limited to aluminum, silver and other metal reflective films; the coating layer includes but is not limited to silicon dioxide film (SiO2), hafnium dioxide film (HfO2) and other dielectric films.

[0065] The two first grating structures 25 of the diffraction waveguide module 100a of the present application are respectively arranged on the inner surfaces of the two first optical waveguide layers 20, which can prevent the first grating structures 25 from being damaged by collision; and compared with the existing technology, the diffraction waveguide module 100a of the present application omits the cover plate, which not only saves the manufacturing cost, but also reduces the thickness of the diffraction waveguide module 100a and the weight of the diffraction waveguide module 100a.

[0066] See also Fig.12The present application also provides a sixth near-eye display device 900 provided with the above-mentioned diffractive waveguide module 100a, and the sixth near-eye display device 900 further includes an image source 32 disposed on the side of the diffractive waveguide module 100a away from the reflective film 26. Optionally, the light outlet of the image source 32 faces the first coupling-in region 252.

[0067] When the sixth near-eye display device 900 is used, the light of the display image generated by the image source 32 enters the two first optical waveguide layers 20 through the two first coupling-in regions 252 respectively, is emitted to the two second coupling-out regions 254 after being totally reflected by the two first optical waveguide layers 20, and then is coupled out of the two second coupling-out regions 254 and emitted to the user's eyes 37.

[0068] This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A diffraction waveguide module, characterized in that: The diffractive waveguide module comprises: an optical waveguide layer, the optical waveguide layer comprising a first optical waveguide layer and a second optical waveguide layer, the first optical waveguide layer and the second optical waveguide layer being stacked with an interval, the first optical waveguide layer comprising a first surface facing the second optical waveguide layer, and the second optical waveguide layer comprising a second surface facing the first optical waveguide layer; and The grating structure includes a first grating structure and a second grating structure. The first grating structure is arranged on the first surface, and the second grating structure is arranged on the second surface.

2. The diffractive waveguide module according to claim 1, characterized in that: The first grating structure includes a first coupling region and a first decoupling region, and the second grating structure includes a second coupling region and a second decoupling region, the first coupling region and the second coupling region are located on one side of the diffraction waveguide module, and the first decoupling region and the second decoupling region are located on the other side of the diffraction waveguide module.

3. The diffractive waveguide module according to claim 2, wherein: The first coupling-in region and the second coupling-in region are both blazed gratings, straight-tooth gratings or helical-tooth gratings; the first coupling-out region and the second coupling-out region are both blazed gratings, straight-tooth gratings or helical-tooth gratings.

4. The diffractive waveguide module according to claim 1, wherein: The first grating structure is a reflection grating, and the second grating structure is a transmission grating.

5. The diffractive waveguide module according to claim 1, characterized in that: The first grating structure and the second grating structure are both reflective gratings. The diffraction waveguide module further includes a reflective film, and the reflective film is stacked on a surface of the optical waveguide layer away from the grating structure.

6. The diffractive waveguide module according to claim 5, characterized in that: The reflective film is a metal reflective film layer, or the reflective film is a coating layer.

7. The diffractive waveguide module according to claim 1, characterized in that: An air gap is provided between the first optical waveguide layer and the second optical waveguide layer.

8. The diffractive waveguide module according to claim 1, wherein: The period range of the grating structure is 200nm-600nm, and the duty cycle range of the grating structure is 0.01-0.

99.

9. The diffractive waveguide module according to claim 1, characterized in that: The depth of the grating structure ranges from 10nm to 300nm.

10. A near-eye display device, comprising the diffraction waveguide module and an image source according to any one of claims 1 to 9, wherein the image source is located on a side of the first optical waveguide layer away from the second optical waveguide layer.

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