Optical display module and head-mounted device

Abstract

The invention discloses an optical display module and a head-mounted device. The optical display module comprises an optical machine, a diffraction waveguide layer, a sealing element and a reflecting film, the optical machine is opposite to the diffraction waveguide layer, a gap is formed between the optical machine and the diffraction waveguide layer, the sealing element is arranged between the optical machine and the diffraction waveguide layer and connected with the optical machine and the diffraction waveguide layer, the reflecting film is arranged on the diffraction waveguide layer, and the sealing element is arranged between the optical machine and the diffraction waveguide layer. And at least part of the reflecting film is located between the sealing piece and the total reflection propagation area of the diffraction waveguide layer, so that the sealing piece and the total reflection propagation area are spaced. Direct contact between the sealing element and the total reflection propagation area of the diffraction waveguide layer is avoided through the reflecting film, the light guide efficiency is guaranteed, an inner protection layer does not need to be arranged on the diffraction waveguide layer, and the thickness and the weight are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of augmented reality, and in particular, relates to an optical display module and a head-mounted device. Background Art

[0002] The optical module of an augmented reality (AR) near-eye display device usually consists of two parts: an optical machine (or light engine) and an optical combiner. The optical machine consists of an image source and a projection lens. The image source is used to generate the image to be displayed, and the projection lens projects the image displayed by the image source to infinity or a specified distance. The optical combiner can transmit the signal light emitted by the optical machine to the human eye in a directionally manner, forming the image to be displayed on the retina; at the same time, the optical combiner has good transmittance to the ambient light in the real world. Through the optical combiner, the human eye can see the real-world scenery and the image projected by the optical machine at the same time; the diffraction optical waveguide is the preferred solution for the optical combiner because of its thin thickness, light weight and good light transmittance.

[0003] The diffraction waveguide is usually composed of several diffraction waveguide layers, at least one protective layer, and adhesive bonding the diffraction waveguide layers and the protective layer. The surface of each diffraction waveguide layer is provided with an in-coupling grating and an out-coupling grating. The in-coupling grating is used to couple the light emitted by the light engine into the diffraction waveguide layer and cause total reflection. After total reflection in the diffraction waveguide layer, the light is transmitted to the out-coupling grating. The out-coupling grating diffracts the light in the diffraction waveguide layer into the free space. After entering the human eye, a virtual image to be displayed is formed on the retina. In addition to the in-coupling grating and the out-coupling grating, the surface of each diffraction waveguide layer may also be provided with a turning grating to achieve requirements such as pupil expansion.

[0004] When the diffraction optical waveguide is assembled with the light engine, there is inevitably a gap between the diffraction optical waveguide and the light engine due to structural design and other reasons. If the AR optical display module is used directly without sealing the gap, impurities such as dust and water vapor will inevitably enter the gap during use or reliability testing. This will cause the light emitted by the light engine to be scattered by dust and water vapor, affecting the clarity of the virtual image displayed by the entire AR optical display module; even when a lot of dust accumulates in the gap, the light emitted by the light engine will be blocked by the accumulated dust, and the light flux entering the diffraction optical waveguide will decrease, which will in turn cause the image brightness of the virtual image displayed by the AR display module to decrease. It can be seen that if the gap is not closed, it will affect the quality of the virtual image displayed by the AR display module.

[0005] In order to seal the gap, the prior art uses a sealant to fix the light engine and the diffraction light waveguide and seal the gap C. Figure 1As shown, in the first case, the sealant 2 is fixed on the inner protective layer 3. Although it does not affect the total reflection propagation in the diffraction waveguide layer 4 and can close the gap C, the thickness and weight of the diffraction light waveguide are increased due to the presence of the inner protective layer 3. Figure 2 As shown, for the second case, the sealant 2 is directly fixed on the diffraction waveguide layer 4. Although the thickness and weight of the diffraction waveguide are reduced, the total reflection propagation of the diffraction waveguide layer 4 will be destroyed, and the performance indicators of the diffraction waveguide layer 4 such as light efficiency and contrast will be reduced. Summary of the invention

[0006] The technical problem solved by the present invention is: how to ensure the light guiding efficiency of the diffractive optical waveguide while reducing the thickness and weight of the diffractive optical waveguide when assembling and sealing the diffractive optical waveguide and the optical engine.

[0007] The present application discloses an optical display module, which includes an optical machine, a diffraction waveguide layer, a seal and a reflective film. The optical machine and the diffraction waveguide layer are opposite to each other and have a gap therebetween. The seal is arranged between the optical machine and the diffraction waveguide layer and are respectively connected to the optical machine and the diffraction waveguide layer. The reflective film is arranged on the diffraction waveguide layer, and at least a portion of the reflective film is located between the seal and a total reflection propagation area of ​​the diffraction waveguide layer, so that the seal is spaced from the total reflection propagation area.

[0008] Optionally, the optical display module further includes a fixing component, wherein the fixing component is connected to the optical machine, and the sealing component is connected to the fixing component.

[0009] Optionally, the reflective film includes a single-layer or multi-layer reflective layer.

[0010] Optionally, the reflective film further includes a protective layer, and the protective layer is disposed on the reflective layer.

[0011] Optionally, the optical display module also includes a transparent film layer, which is arranged on the surface of the diffraction waveguide layer close to the optical machine; the reflective film is arranged on the outer surface of the transparent film layer close to the optical machine, or the reflective film is arranged between the transparent film layer and the diffraction waveguide layer.

[0012] Optionally, the reflective film has a plurality of reflective regions, and the reflectivities of the respective reflective regions are different.

[0013] Optionally, the sealing member is an adhesive.

[0014] Optionally, the coupling-in grating of the diffraction waveguide layer is a reflection grating, and the coupling-in grating is arranged on a surface of the diffraction waveguide layer away from the optical engine.

[0015] Optionally, the coupling-in grating of the diffraction waveguide layer is a transmission grating, and the coupling-in grating is arranged on a surface of the diffraction waveguide layer close to the optical engine.

[0016] The present application also discloses a head-mounted device, which includes the above-mentioned optical display module.

[0017] An optical display module and a head-mounted device disclosed in the present invention have the following technical effects:

[0018] A reflective film is provided on the diffraction waveguide layer, and the reflective film is used to avoid direct contact between the seal and the total reflection propagation area of ​​the diffraction waveguide layer, thereby ensuring the light guiding efficiency. At the same time, there is no need to provide an inner protective layer on the diffraction waveguide layer, thereby reducing the thickness and weight of the diffraction optical waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of assembling the optical engine and the diffractive optical waveguide in the prior art;

[0020] Figure 2 It is a schematic diagram of assembling a light engine and a diffractive light waveguide in another prior art;

[0021] Figure 3 is a schematic diagram of an optical display module according to Embodiment 1 of the present invention;

[0022] Figure 4 is a schematic diagram of an optical display module according to another implementation manner of the first embodiment of the present invention;

[0023] Figure 5A , Figure 5B , Figure 5C A top view of a diffraction waveguide layer having a reflective film of different shapes according to a first embodiment of the present invention;

[0024] Figure 6 A top view of a diffraction waveguide layer with a turning grating according to the first embodiment of the present invention;

[0025] Figure 7 It is a schematic diagram of the composition of the reflective film of the first embodiment of the present invention;

[0026] Fig. 8A , Figure 8B A top view of a diffraction waveguide layer when the reflective film according to the first embodiment of the present invention has a plurality of reflective regions;

[0027] Fig. 9 is another schematic diagram of the composition of the reflective film of the first embodiment of the present invention;

[0028] Fig.10 is a schematic diagram of a partial structure of an optical display module according to Embodiment 1 of the present invention;

[0029] Fig.11 is a schematic diagram of an optical display module having two diffractive waveguide layers in Embodiment 1 of the present invention;

[0030] Fig.12 is a schematic diagram of an optical display module having two diffractive waveguide layers and an outer protective layer in Embodiment 1 of the present invention;

[0031] Fig.13 FIG. 1 is a schematic diagram of an optical display module in another implementation manner according to the first embodiment of the present invention.

[0032] The corresponding relationship between the reference numerals and the component names is as follows:

[0033] 10-optical machine, 20-diffraction waveguide layer, 21-coupling grating, 22-coupling grating, 23-turning grating, 30-seal, 40-reflection film, 41-reflection layer, 42-protective layer, 43-gluing layer, 50-transparent film layer, 60-outer protective layer, 70-fixing part. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Before describing the various embodiments of the present application in detail, the technical concept of the present application is briefly described first: in the prior art, when sealing and assembling the diffraction waveguide and the optical machine, if the seal is directly in contact with the diffraction waveguide layer, the total reflection propagation process in the diffraction waveguide layer will be destroyed, and the light guiding efficiency will be reduced. If an inner protective layer is provided outside the diffraction waveguide layer, and the seal is connected to the inner protective layer, the thickness and weight of the diffraction waveguide will be increased. To this end, the present application provides an optical display module, in which a reflective film is provided on the diffraction waveguide layer, and the reflective film is used to avoid direct contact between the seal and the total reflection propagation area of ​​the diffraction waveguide layer, thereby ensuring the light guiding efficiency. At the same time, there is no need to provide an inner protective layer on the diffraction waveguide layer, thereby reducing the thickness and weight. In addition, it can ensure that the display uniformity, MTF (Modulation Transfer Function) and contrast of the diffraction waveguide layer are not affected.

[0036] Specifically, Figure 3As shown, the optical display module of the first embodiment includes an optical engine 10, a diffraction waveguide layer 20, a seal 30 and a reflective film 40. The optical engine 10 and the diffraction waveguide layer 20 are opposite to each other and have a gap therebetween. The seal 30 is disposed between the optical engine 10 and the diffraction waveguide layer 20 and is respectively connected to the optical engine 10 and the diffraction waveguide layer 20. The reflective film 40 is disposed on the diffraction waveguide layer 20, and at least a portion of the reflective film 40 is located between the seal 30 and the total reflection propagation area of ​​the diffraction waveguide layer 20, so that the seal 30 is spaced from the total reflection propagation area to prevent the seal 30 from destroying the light guiding process of the total reflection propagation area.

[0037] Exemplarily, the total reflection propagation region is the light transmission region between the coupling-in grating 21 and the coupling-out grating 22 of the diffraction waveguide layer 20, such as Figure 5A The dotted area A in Figure 5B The dotted area B in Figure 5C The dotted area C in the figure can represent the total reflection propagation area, and the reflective film 40 can be located in the total reflection propagation area as a whole, or a part of the reflective film 40 can be located in the total reflection propagation area. In other embodiments, if the surface of the diffraction waveguide layer 30 is provided with a turning grating 23 in addition to the coupling-in grating 21 and the coupling-out grating 22, that is, the turning grating 23 is provided between the coupling-in grating 21 and the coupling-out grating 22, the total reflection propagation area can be defined as the light transmission area between the coupling-in grating 21 and the turning grating 23, for example, Figure 6 The dotted area D in the middle may represent the total reflection propagation area. The light introduced through the coupling-in grating 21 passes through the total reflection propagation area to reach the turning grating 23. The turning grating 23 turns the light and directs the light to the coupling-out grating 22. Finally, the light is projected from the coupling-out grating 22 to the human eye.

[0038] Furthermore, at least a partial structure (partial structure or overall structure) of the seal 30 abuts against the reflective film 40, and the seal 30 is separated from the diffraction waveguide layer 20 by the reflective film 40, so that the seal 30 does not directly contact the total reflection propagation area on the diffraction waveguide layer 20.

[0039] Further, in order to ensure that the light of the optical machine 10 can be irradiated into the coupling grating 21, the seal 30 needs to be arranged around the gap between the optical machine 10 and the diffraction waveguide layer 20 to prevent the seal 30 from blocking the light generated by the optical machine 10. At the same time, the coupling grating 21 is arranged relative to the optical machine 10. When the coupling grating 21 receives the light emitted by the optical machine 10 and performs total reflection propagation, the total reflection propagation area will inevitably be in direct contact with the seal 30, that is, at least part of the structure of the seal 30 will overlap with the total reflection propagation area. If no measures are taken, the direct contact of the seal 30 will affect the light guiding process of the total reflection propagation area. Therefore, by arranging a reflective film 40 between at least part of the structure of the seal 30 and the total reflection propagation area, the direct contact between the seal 30 and the total reflection propagation area is avoided, thereby ensuring the light guiding efficiency, while ensuring that the display uniformity, MTF and contrast of the diffraction waveguide layer are not affected. Comprehensive optical performance. In essence, the total reflection at the contact point between the reflective film 40 and the total reflection propagation area will also be affected, and the reflection effect of the reflective film 40 can return the light to the total reflection propagation area, thereby offsetting the effect.

[0040] Exemplarily, the coupling-in grating 21 and the coupling-out grating 22 of the diffraction waveguide layer 20 are both reflective gratings. In this case, the coupling-in grating 21 and the coupling-out grating 22 are both arranged on the surface of the diffraction waveguide layer 20 away from the optical engine 10, that is, the coupling-in grating 21 and the coupling-out grating 22 are both arranged on the inner surface of the diffraction waveguide layer 20. The reflective grating can be a reflective surface relief grating or a reflective volume holographic grating. In other embodiments, such as Figure 4 As shown, the coupling-in grating 21 of the diffraction waveguide layer 20 can be a transmission grating. In this case, the coupling-in grating 21 is arranged on the surface of the diffraction waveguide layer 20 close to the optical engine 10, that is, the coupling-in grating 21 is arranged on the outer surface of the diffraction waveguide layer 20.

[0041] Furthermore, the position, shape and area of ​​the reflective film 40 can be set according to actual needs, and factors such as the position and size of the seal to be set should be considered. In order for the light to smoothly enter the coupling grating 21 and be emitted from the coupling grating 22, the reflective film 40 needs to avoid blocking the coupling grating 21 and the coupling grating 22. The reflective film 40 can be set around or adjacent to the coupling grating 21. For example, Figure 5A As shown, the reflective film 40 is in the shape of a ring and is disposed around the coupling-in grating 21; Figure 5B As shown, the reflective film 40 is in the shape of a semicircular ring and is disposed around the coupling-in grating 21; Figure 5C As shown, the reflective film 40 is rectangular in shape and is disposed adjacent to the coupling-in grating 21 .

[0042] Specifically, Figure 7As shown in a and b in FIG. 1 , the reflective film 40 includes a single-layer or multi-layer reflective layer 41. The reflective layer 41 can be a metal reflective layer, a dielectric reflective layer, or a combination of a metal reflective layer and a dielectric reflective layer. The reflectivity of the reflective layer 41 for the visible light band can be set according to requirements. As a preferred embodiment, the reflectivity of the reflective layer 41 for the visible light band is greater than 95%.

[0043] In another embodiment, the reflective film 40 has a plurality of reflective regions, and the reflectivity of each reflective region is different to further improve the display uniformity of the diffraction light waveguide. In the diffraction waveguide layer, the energy loss of light is different on different light transmission paths, so the intensity of light finally emitted from the outcoupling grating is not uniform, that is, the outgoing light intensity in some outcoupling regions is less than the outgoing light intensity in other regions. At least part of the reflective film 40 is located on the light transmission path of the diffraction waveguide layer. Therefore, the light intensity can be adjusted by setting various reflective regions with different reflectivities on the reflective film 40. For example, a reflective region with a smaller reflectivity can be set on a shorter light transmission path, and a reflective region with a larger reflectivity can be set on a longer light transmission path. For example, as Fig. 8A As shown, the reflective film 40 has six reflective regions R1, R2, R3, R4, R5, and R6 with different reflectivities. Figure 8B As shown, the reflective film 40 has three reflective regions R1, R2, and R3 with different reflectivities. It should be noted that the number, shape, and reflectivity of the reflective regions on the reflective film 40 are set to achieve the requirement of improving the display uniformity of the diffraction light waveguide, and this embodiment does not specifically limit this.

[0044] Furthermore, if Figure 7 As shown in a and b in FIG. 1 , the reflective film 40 further includes a protective layer 42, which is disposed on the reflective layer 41. The protective layer 42 may be disposed on one or both sides of the reflective layer 41 to prevent corrosion from external air and the outgassing effect of the diffraction waveguide layer 20 (outgassing refers to the fact that when the waveguide substrate is a resin material, the water vapor absorbed in the resin will be slowly released over time. In the absence of a protective layer, the water vapor may corrode the reflective layer. ， Therefore, the performance or reliability of the reflective layer is reduced.) The number of protective layers 42 can be set according to actual needs.

[0045] For example, the reflective film 40 may be prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD), spraying, dipping, printing, laminating, etc. The preparation process of the reflective film 40 is described below by taking the laminating process as an example.

[0046] Specifically, Fig. 9As shown, the reflective film 40 is composed of a reflective layer 41, a glue layer 43, and a protective layer 42. The reflective layer 41 and the protective layer 42 are prefabricated sheet materials, and then the prefabricated sheet reflective layer 41 and the protective layer 42 are cut into preset shapes according to requirements, and then bonded to the diffraction waveguide layer 20 through the glue layer 43. Exemplarily, the glue layer 43 is composed of a transparent glue material, preferably a transparent sheet OCA (or OCR glue). The reflective layer 41 and the protective layer 42 can be a complete sheet during the prefabrication process, and the reflective layer 41 and the protective layer 42 are already bonded together during the prefabrication; during the prefabrication process, the reflective layer 41 and the protective layer 42 can also be prefabricated into separate sheets. When preparing the diffraction optical waveguide, the reflective layer 41 is first connected to the diffraction waveguide layer 20 through the glue layer 43, and then the protective layer 42 is connected to the reflective layer 41 (in this case, a glue layer 43 needs to be provided between the protective layer 42 and the reflective layer 41).

[0047] Furthermore, the optical display module further includes a transparent film layer 50, which is disposed on the surface of the diffraction waveguide layer 20 close to the optical engine 10. Fig.10 As shown, the reflective film 40 is disposed on the outer surface of the transparent film layer 50 close to the optical machine 10. In another embodiment, the reflective film 40 is disposed between the transparent film layer 50 and the diffraction waveguide layer 20, that is, the reflective film 40 is disposed on the inner surface of the transparent film layer 50 away from the optical machine 10. Optionally, the transparent film layer 50 includes at least one of a hardening layer, an anti-reflection layer, and an anti-fingerprint layer. When the transparent film layer 50 includes at least two of the hardening layer, the anti-reflection layer, and the anti-fingerprint layer, the reflective film 40 may also be disposed between two different layers of the transparent film layer 50, for example, between the hardening layer and the anti-reflection layer.

[0048] Furthermore, the optical display module also includes an outer protective layer 60, which is arranged on the side of the diffraction waveguide layer 20 away from the optical machine 10, and the outer protective layer 60 and the diffraction waveguide layer 20 are spaced apart to form an air layer therebetween, thereby ensuring the total reflection propagation of the diffraction waveguide layer 20 and protecting the diffraction waveguide layer 20 at the same time.

[0049] like Fig.11 As shown, in one embodiment, the number of the diffraction waveguide layers 20 may be two, and the diffraction waveguide layers 20 are arranged at intervals, and an air layer is formed between the two. Fig.11 The coupling-in grating 21 and the coupling-out grating 22 of the outermost diffraction waveguide layer 20 are both transmission gratings and are disposed on the inner surface of the diffraction waveguide layer 20. The coupling-in grating 21 and the coupling-out grating 22 are not exposed to the external environment, so there is no need to dispose an outer protective layer 60 on the outer side of the diffraction waveguide layer 20. Fig.12As shown, in another embodiment, when the number of the diffraction waveguide layers 20 is two, the coupling-in grating 21 and the coupling-out grating 22 of the outermost diffraction waveguide layer 20 are both reflection gratings and are both arranged on the outer surface of the diffraction waveguide layer 20. At this time, the coupling-in grating 21 and the coupling-out grating 22 will be exposed to the external environment, so an outer protective layer 60 can be arranged on the outer side of the outermost diffraction waveguide layer 20, that is, from the inside to the outside, the first diffraction waveguide layer 20, the second diffraction waveguide layer 20, and the outer protective layer 60 are arranged in sequence to protect the coupling-in grating 21 and the coupling-out grating 22 on the outermost diffraction waveguide layer 20. The inner surface mentioned here refers to the surface of the diffraction waveguide layer 20 facing the optical machine 10, the outer surface refers to the surface of the diffraction waveguide layer 20 facing away from the optical machine 10, and the outer side mentioned here refers to the side of the diffraction waveguide layer 20 facing away from the optical machine 10. In other embodiments, the number of diffraction waveguide layers 20 may be 3 or more, and the specific number may be set according to actual needs. In summary, in the case where there are multiple diffraction waveguide layers 20, when the outer surface of the outermost diffraction waveguide layer 20 is provided with at least one of the coupling-in grating 21, the coupling-out grating 22, and the turning grating, an outer protective layer needs to be provided on the outer side of the outermost diffraction waveguide layer 20 to protect the grating.

[0050] like Fig.13 As shown, in another embodiment, the optical display module further includes a fixing member 70, the fixing member 70 is connected to the optical engine 10, and the sealing member 30 is connected to the fixing member 70. Exemplarily, the fixing member 70 is a cylinder, and the fixing member 70 is disposed on the periphery of the optical engine 10.

[0051] As a preferred embodiment, the sealing member 30 is an adhesive. During assembly, the adhesive is first applied around the coupling grating 21 of the diffraction waveguide layer 20, wherein the diffraction waveguide layer 20 has pre-formed a reflective film 40, and the adhesive is partially applied to the reflective film 40, and then the optical engine 10 or the fixing member 70 is adhered to the adhesive, so that the gap between the optical engine 10 and the diffraction waveguide layer 20 can be sealed, and the optical engine 10 can also be fixed. In other embodiments, when applying the adhesive, the adhesive can also be applied to the corresponding position of the optical engine 10 or the fixing member 70, so that the optical engine 10 or the fixing member 70 is adhered to the diffraction waveguide layer 20 and the reflective film 40.

[0052] The optical display module disclosed in the first embodiment uses a reflective film to prevent the seal from directly contacting the total reflection propagation area of ​​the diffraction waveguide layer, thereby ensuring light guiding efficiency. At the same time, there is no need to provide an inner protective layer on the diffraction waveguide layer, thereby reducing thickness and weight.

[0053] The second embodiment also discloses a head-mounted device, which includes the optical display module in the first embodiment. The head-mounted device can reduce the weight of the device while ensuring the light guiding efficiency, which is conducive to miniaturized design.

[0054] The head-mounted device can be an augmented reality device, such as augmented reality glasses. In the example of augmented reality glasses, the head-mounted device can be configured to transfer data to an external processing device and receive data from the external processing device through a signal connection, and the signal connection can be a wired connection, a wireless connection, or a combination thereof. However, in other cases, the head-mounted device can be used as a stand-alone device, that is, data processing is performed on the head-mounted device itself. The signal connection can be configured to carry any kind of data, such as image data (e.g., still images and / or full motion video, including 2D and 3D images), audio, multimedia, voice, and / or any other type of data. The external processing device can be, for example, a game console, a personal computer, a tablet computer, a smart phone, or other type of processing device. The signal connection can be, for example, a universal serial bus (USB) connection, a Wi-Fi connection, a Bluetooth or Bluetooth low energy (BLE) connection, an Ethernet connection, a cable connection, a DSL connection, a cellular connection (e.g., 3G, LTE / 4G or 5G), etc., or a combination thereof. Additionally, the external processing device may communicate with one or more other external processing devices via a network, which may be or include, for example, a local area network (LAN), a wide area network (WAN), an intranet, a metropolitan area network (MAN), the global Internet, or a combination thereof.

[0055] It should be noted that it is understandable that a complete augmented reality glasses should also have other necessary basic components, but the other components are not the focus of this embodiment, so they are not shown in the drawings and are not described in detail in the specification, and these components are well-known technologies to those skilled in the art.

[0056] The specific implementation methods of the present invention are described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments can be modified and improved without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents. These modifications and improvements should also be within the scope of protection of the present invention.

Claims

1. An optical display module, characterized in that: The optical display module includes an optical machine, a diffraction waveguide layer, a seal and a reflective film. The optical machine and the diffraction waveguide layer are opposite to each other and have a gap therebetween. The seal is disposed between the optical machine and the diffraction waveguide layer and are respectively connected to the optical machine and the diffraction waveguide layer. The reflective film is disposed on the diffraction waveguide layer, and at least a portion of the reflective film is located between the seal and a total reflection propagation region of the diffraction waveguide layer, so that the seal is spaced from the total reflection propagation region.

2. The optical display module according to claim 1, characterized in that: The optical display module further includes a fixing member, wherein the fixing member is connected to the optical machine, and the sealing member is connected to the fixing member.

3. The optical display module according to claim 1, characterized in that: The reflective film includes a single-layer or multi-layer reflective layer.

4. The optical display module according to claim 3, characterized in that: The reflective film further includes a protective layer, and the protective layer is disposed on the reflective layer.

5. The optical display module according to claim 3, characterized in that: The optical display module also includes a transparent film layer, which is arranged on the surface of the diffraction waveguide layer close to the optical machine; the reflective film is arranged on the outer surface of the transparent film layer close to the optical machine, or the reflective film is arranged between the transparent film layer and the diffraction waveguide layer.

6. The optical display module according to claim 1, characterized in that: The reflective film has a plurality of reflective regions, and the reflectivities of the reflective regions are different.

7. The optical display module according to claim 1, characterized in that: The sealing member is an adhesive.

8. The optical display module according to claim 1, characterized in that: The coupling-in grating of the diffraction waveguide layer is a reflection grating, and the coupling-in grating is arranged on the surface of the diffraction waveguide layer away from the optical engine.

9. The optical display module according to claim 1, characterized in that: The coupling-in grating of the diffraction waveguide layer is a transmission grating, and the coupling-in grating is arranged on the surface of the diffraction waveguide layer close to the optical engine.

10. A head mounted device, characterized in that: The head-mounted device comprises the optical display module according to any one of claims 1 to 9.

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