Optical display modules and head-mounted devices

Abstract

This invention discloses an optical display module and a head-mounted device. The optical display module includes an optical engine, a diffractive waveguide layer, a sealing element, and a reflective film. The optical engine is opposite to the diffractive waveguide layer and has a gap. The sealing element is disposed between the optical engine and the diffractive waveguide layer and is connected to both the optical engine and the diffractive waveguide layer. The reflective film is disposed on the diffractive waveguide layer, and at least a portion of the reflective film is located between the sealing element and the total internal reflection propagation region of the diffractive waveguide layer, thereby spacing the sealing element from the total internal reflection propagation region. The reflective film avoids direct contact between the sealing element and the total internal reflection propagation region of the diffractive waveguide layer, ensuring light guiding efficiency. Furthermore, it eliminates the need for an inner protective layer on the diffractive waveguide layer, reducing thickness and weight.

Description

Technical Field

[0001] This invention belongs to the field of augmented reality technology, specifically relating to an optical display module and a head-mounted device. Background Technology

[0002] The optical module of an augmented reality (AR) near-eye display device typically consists of two parts: an optical engine (or light engine) and an optical combiner. The optical engine comprises an image source and a projection lens. The image source generates the image to be displayed, and the projection lens projects the image from the image source to infinity or a specified distance. The optical combiner directs the signal light emitted from the optical engine to the human eye, forming the image to be displayed on the retina. Simultaneously, the optical combiner has good transmittance to ambient light from the real world, allowing the human eye to simultaneously see both real-world objects and the image projected by the optical engine. Diffractive waveguides, due to their thinness, light weight, and high light transmittance, are the preferred solution for the optical combiner.

[0003] A diffractive waveguide typically consists of several diffractive waveguide layers, at least one protective layer, and an adhesive bonding the diffractive waveguide layers and the protective layer. Each diffractive waveguide layer has a coupling grating and a coupling grating on its surface. The coupling grating couples the light emitted by the optical engine into the diffractive waveguide layer, where it undergoes total internal reflection. After total internal reflection within the diffractive waveguide layer, the light is transmitted to the coupling grating, which diffracts the light within the diffractive waveguide layer into free space. Upon entering the human eye, this diffractive light forms a virtual image on the retina. In addition to the coupling grating and coupling grating, each diffractive waveguide layer may also have a deflection grating to achieve requirements such as exit pupil expansion.

[0004] When assembling a diffractive waveguide and an optical engine, a gap inevitably exists between them due to structural design and other reasons. If this gap is not sealed before using the AR optical display module, dust, moisture, and other impurities will inevitably enter during use or reliability testing. This will cause the light emitted by the optical engine to be scattered by dust and moisture, affecting the clarity of the virtual image displayed by the entire AR optical display module. Furthermore, when a significant amount of dust accumulates in the gap, it can block the light emitted by the optical engine, reducing the luminous flux entering the diffractive waveguide and consequently decreasing the brightness of the virtual image displayed by the AR display module. Therefore, leaving this gap unsealed will affect the quality of the virtual image displayed by the AR display module.

[0005] To seal the gap, existing technology uses sealant to fix the optical engine to the diffractive waveguide and seal the gap C. For example... Figure 1As shown, in the first case, the sealant 2 is fixed to the inner protective layer 3. Although this does not affect the total internal reflection propagation in the diffraction waveguide layer 4 and can seal the gap C, the presence of the inner protective layer 3 increases the thickness and weight of the diffraction waveguide; as Figure 2 As shown, in the second case, the sealant 2 is directly fixed on the diffraction waveguide layer 4. Although this reduces the thickness and weight of the diffraction waveguide, it will disrupt the total internal reflection propagation of the diffraction waveguide layer 4 and reduce the optical efficiency, contrast and other performance indicators of the diffraction waveguide layer 4. Summary of the Invention

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

[0007] This application discloses an optical display module, which includes an optical engine, a diffraction waveguide layer, a sealing element, and a reflective film. The optical engine is opposite to the diffraction waveguide layer and has a gap. The sealing element is disposed between the optical engine and the diffraction waveguide layer and is connected to both the optical engine 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 total internal reflection propagation region of the sealing element and the diffraction waveguide layer, such that the sealing element is spaced apart from the total internal reflection propagation region.

[0008] Optionally, the optical display module further includes a fixing member connected to the optomechanical system, and the sealing member is connected to the fixing member.

[0009] Optionally, the reflective film comprises a single layer or multiple layers of reflective layers.

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

[0011] Optionally, the optical display module further includes a transparent film layer disposed on the surface of the diffraction waveguide layer near the optical engine; the reflective film is disposed on the outer surface of the transparent film layer near the optical engine, or the reflective film is disposed between the transparent film layer and the diffraction waveguide layer.

[0012] Optionally, the reflective film has multiple reflective regions, each with a different reflectivity.

[0013] Optionally, the sealant is an adhesive.

[0014] Optionally, the coupling grating of the diffraction waveguide layer is a reflection grating, and the coupling grating is disposed on the surface of the diffraction waveguide layer away from the optomechanism.

[0015] Optionally, the coupling grating of the diffraction waveguide layer is a transmission grating, and the coupling grating is disposed on the surface of the diffraction waveguide layer near the optomechanism.

[0016] This application also discloses a head-mounted device, which includes the aforementioned optical display module.

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

[0018] A reflective film is placed on the diffractive waveguide layer to prevent the seal from directly contacting the total internal reflection propagation area of ​​the diffractive waveguide layer, thus ensuring light guiding efficiency. At the same time, there is no need to place an inner protective layer on the diffractive waveguide layer, thereby reducing the thickness and weight of the diffractive waveguide. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the assembly of an optical engine and a diffractive waveguide in the existing technology.

[0020] Figure 2 This is a schematic diagram of the assembly of an optical engine and a diffractive waveguide in another existing technology.

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

[0022] Figure 4 This is a schematic diagram of an optical display module in another embodiment of the present invention;

[0023] Figure 5A , Figure 5B , Figure 5C This is a top view of a diffraction waveguide layer with a reflective film of a different shape, according to Embodiment 1 of the present invention.

[0024] Figure 6 This is a top view of a diffraction waveguide layer with a folding grating according to Embodiment 1 of the present invention.

[0025] Figure 7 This is a schematic diagram of the composition of the reflective film in Embodiment 1 of the present invention;

[0026] Figure 8A , Figure 8B This is a top view of the diffraction waveguide layer when the reflective film of Embodiment 1 of the present invention has multiple reflective regions;

[0027] Figure 9 This is a schematic diagram of another component of the reflective film in Embodiment 1 of the present invention;

[0028] Figure 10 This is a partial structural schematic diagram of the optical display module according to Embodiment 1 of the present invention;

[0029] Figure 11 This is a schematic diagram of an optical display module with two diffraction waveguide layers in Embodiment 1 of the present invention;

[0030] Figure 12 This is a schematic diagram of an optical display module with two diffraction waveguide layers and an outer protective layer in Embodiment 1 of the present invention;

[0031] Figure 13 This is a schematic diagram of an optical display module in another embodiment of the present invention.

[0032] The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0033] 10-Optics, 20-Diffraction waveguide layer, 21-Coupled grating, 22-Coupled grating, 23-Turning grating, 30-Sealing element, 40-Reflective film, 41-Reflective layer, 42-Protective layer, 43-Adhesive layer, 50-Transparent film layer, 60-Outer protective layer, 70-Fixing element. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Before describing the various embodiments of this application in detail, the technical concept of this application is first briefly described: In the prior art, when sealing and assembling a diffractive waveguide and an optomechanical system, if the sealing element directly contacts the diffractive waveguide layer, it will disrupt the total internal reflection propagation process in the diffractive waveguide layer and reduce the light guiding efficiency. If an inner protective layer is set outside the diffractive waveguide layer and the sealing element is connected to the inner protective layer, the thickness and weight of the diffractive waveguide will increase. To this end, this application provides an optical display module in which a reflective film is set on the diffractive waveguide layer. The reflective film avoids direct contact between the sealing element and the total internal reflection propagation area of ​​the diffractive waveguide layer, ensuring the light guiding efficiency. At the same time, there is no need to set an inner protective layer on the diffractive waveguide layer, reducing the thickness and weight. In addition, it can also ensure that the overall optical performance of the diffractive waveguide layer, including display uniformity, MTF (Modulation Transfer Function), and contrast, is not affected.

[0036] Specifically, such as Figure 3As shown, the optical display module of this embodiment includes an optical engine 10, a diffraction waveguide layer 20, a sealing element 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. The sealing element 30 is disposed between the optical engine 10 and the diffraction waveguide layer 20 and is connected to the optical engine 10 and the diffraction waveguide layer 20 respectively. 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 sealing element 30 and the total internal reflection propagation area of ​​the diffraction waveguide layer 20, so that the sealing element 30 is spaced from the total internal reflection propagation area, thereby preventing the sealing element 30 from disrupting the light guiding process of the total internal reflection propagation area.

[0037] For example, the total internal reflection propagation region is the light transmission region between the input grating 21 and the output grating 22 of the diffraction waveguide layer 20, such as... Figure 5A The dashed area A in the middle, such as Figure 5B The dashed area B in the text, such as Figure 5C The dashed area C in the diagram can represent the total internal reflection propagation region. The reflective film 40 can be entirely located within the total internal reflection propagation region, or a portion of the reflective film 40 can be located within the total internal reflection propagation region. In other embodiments, if the surface of the diffraction waveguide layer 30 is provided with a transition grating 23 in addition to the coupling grating 21 and the coupling grating 22, that is, the transition grating 23 is provided between the coupling grating 21 and the coupling grating 22, then the total internal reflection propagation region can be defined as the light transmission region between the coupling grating 21 and the transition grating 23. For example, in... Figure 6 The dashed area D can represent the total internal reflection propagation area. The light rays introduced through the coupling grating 21 reach the turning grating 23 through the total internal reflection propagation area. The turning grating 23 turns the light rays and guides them to the coupling grating 22. Finally, the light rays are projected from the coupling grating 22 to the human eye.

[0038] Furthermore, at least a portion (partial or overall) of the seal 30 abuts against the reflective film 40, thereby separating the seal 30 from the diffraction waveguide layer 20, so that the seal 30 does not directly contact the total internal reflection propagation region on the diffraction waveguide layer 20.

[0039] Furthermore, to ensure that the light from the optomechanical engine 10 can illuminate the coupling grating 21, the sealing element 30 needs to be positioned around the gap between the optomechanical engine 10 and the diffraction waveguide layer 20. This prevents the sealing element 30 from blocking the light generated by the optomechanical engine 10. Simultaneously, the coupling grating 21 is positioned opposite the optomechanical engine 10. When the light emitted by the optomechanical engine 10 is received by the coupling grating 21 and undergoes total internal reflection, the total internal reflection propagation area will inevitably come into direct contact with the sealing element 30. That is, at least a portion of the structure of the sealing element 30 will overlap with the total internal reflection propagation area. If no measures are taken, this direct contact will affect the light guiding process of the total internal reflection propagation area. Therefore, by setting a reflective film 40 between at least a portion of the structure of the sealing element 30 and the total internal reflection propagation area, direct contact between the sealing element 30 and the total internal reflection propagation area is avoided, thereby ensuring light guiding efficiency and ensuring that the overall optical performance, including the display uniformity, MTF, and contrast of the diffraction waveguide layer, is not affected. In fact, total reflection at the contact point between the reflective film 40 and the total reflection propagation area is also affected. The reflective effect of the reflective film 40 can return the light to the total reflection propagation area, thereby canceling out the effect.

[0040] For example, the coupling grating 21 and coupling grating 22 of the diffraction waveguide layer 20 are both reflection gratings. In this case, both the coupling grating 21 and coupling grating 22 are disposed on the surface of the diffraction waveguide layer 20 away from the optomechanical 10, that is, both the coupling grating 21 and coupling grating 22 are disposed on the inner surface of the diffraction waveguide layer 20. The reflection 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 grating 21 of the diffraction waveguide layer 20 can be a transmission grating. In this case, the coupling grating 21 is disposed on the surface of the diffraction waveguide layer 20 near the optomechanical 10, that is, the coupling grating 21 is disposed on the outer surface of the diffraction waveguide layer 20.

[0041] Furthermore, the position, shape, and size of the reflective film 40 can be set according to actual needs, taking into account factors such as the location and size of the sealing element. To ensure light smoothly enters the coupling grating 21 and exits from the coupling grating 22, the reflective film 40 needs to avoid obstructing the coupling grating 21 and the coupling grating 22. The reflective film 40 can be positioned around or adjacent to the coupling grating 21. For example, such as... Figure 5A As shown, the reflective film 40 is annular in shape and is disposed around the coupling grating 21; as Figure 5B As shown, the reflective film 40 is semi-circular in shape and is disposed around the coupling grating 21; as Figure 5C As shown, the reflective film 40 is rectangular in shape and is disposed near the coupling grating 21.

[0042] Specifically, such as Figure 7As shown in a and b, the reflective film 40 includes a single layer or multiple layers of reflective layers 41. The reflective layer 41 can be a metallic reflective layer, a dielectric reflective layer, or a combination of both. The reflectivity of the reflective layer 41 in the visible light band can be set according to requirements. In a preferred embodiment, the reflectivity of the reflective layer 41 in the visible light band is greater than 95%.

[0043] In another embodiment, the reflective film 40 has multiple reflective regions with different reflectivities to further improve the display uniformity of the diffractive waveguide. Within the diffractive waveguide layer, light energy loss varies along different light transmission paths, resulting in uneven intensity of the light emitted from the coupling grating; that is, the emitted light intensity in some coupling regions is less than that in others. Since at least a portion of the reflective film 40 lies along the light transmission path of the diffractive waveguide layer, the light intensity can be adjusted by providing reflective regions with different reflectivities on the reflective film 40. For example, reflective regions with lower reflectivity can be provided along shorter light transmission paths, while reflective regions with higher reflectivity can be provided along longer light transmission paths. For example, as shown... Figure 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 all set to meet the requirement of improving the display uniformity of the diffractive waveguide, and this embodiment does not impose any particular limitation.

[0044] Furthermore, such as Figure 7 As shown in a and b, the reflective film 40 also includes a protective layer 42, which is disposed on the reflective layer 41. The protective layer 42 can be disposed on one or both sides of the reflective layer 41 to prevent corrosion from external air and the effects of gas release from the diffraction waveguide layer 20 (gas release refers to the slow release of water vapor absorbed in the resin over time when the waveguide substrate is made of resin material. Without a protective layer, water vapor may corrode the reflective layer, thus reducing its performance or reliability). The number of protective layers 42 can be set according to actual needs.

[0045] For example, the reflective film 40 can be prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD), spraying, dip coating, printing, lamination, etc. The preparation process of the reflective film 40 is described below using the lamination process as an example.

[0046] Specifically, such as Figure 9As shown, the reflective film 40 consists of a reflective layer 41, an adhesive layer 43, and a protective layer 42. The reflective layer 41 and the protective layer 42 are prefabricated sheet materials. These prefabricated sheet materials are then cut into predetermined shapes according to requirements and bonded to the diffraction waveguide layer 20 via the adhesive layer 43. For example, the adhesive layer 43 is made of a transparent adhesive, preferably a transparent sheet of OCA (or OCR adhesive). During the prefabrication process, the reflective layer 41 and the protective layer 42 can be a single, complete sheet, in which case they are already bonded together. Alternatively, during prefabrication, the reflective layer 41 and the protective layer 42 can be prefabricated as separate sheets. When preparing the diffraction waveguide, the reflective layer 41 is first connected to the diffraction waveguide layer 20 via the adhesive layer 43, and then the protective layer 42 is connected to the reflective layer 41 (in which case the adhesive layer 43 needs to be placed between the protective layer 42 and the reflective layer 41).

[0047] Furthermore, the optical display module also includes a transparent film layer 50, which is disposed on the surface of the diffraction waveguide layer 20 near the optomechanical system 10. For example... Figure 10 As shown, the reflective film 40 is disposed on the outer surface of the transparent film layer 50 near the optomechanical system 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 optomechanical system 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, anti-reflection layer, and 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 disposed on the side of the diffraction waveguide layer 20 away from the optomechanical 10. The outer protective layer 60 and the diffraction waveguide layer 20 are spaced apart, forming an air layer between them. This ensures total internal reflection propagation of the diffraction waveguide layer 20 and also protects the diffraction waveguide layer 20.

[0049] like Figure 11 As shown, in one embodiment, there may be two diffraction waveguide layers 20, which are spaced apart and form an air layer between them. Figure 11 The outermost diffraction waveguide layer 20 has two transmission gratings, the insertion grating 21 and the output grating 22, both located on the inner surface of the diffraction waveguide layer 20. Since the insertion grating 21 and the output grating 22 are not exposed to the external environment, an outer protective layer 60 is not required on the outside of the diffraction waveguide layer 20. Figure 12As shown, in another embodiment, when there are two diffraction waveguide layers 20, the coupling grating 21 and coupling grating 22 of the outermost diffraction waveguide layer 20 are both reflection gratings and are both disposed on the outer surface of the diffraction waveguide layer 20. In this case, the coupling grating 21 and coupling grating 22 will be exposed to the external environment. Therefore, an outer protective layer 60 can be disposed 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 disposed alternately to protect the coupling grating 21 and coupling 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 engine 10, the outer surface refers to the surface of the diffraction waveguide layer 20 facing away from the optical engine 10, and the outer side refers to the side of the diffraction waveguide layer 20 facing away from the optical engine 10. In other embodiments, the number of diffraction waveguide layers 20 can be three or more, and the specific number can be set according to actual needs. In summary, when there are multiple diffraction waveguide layers 20, and at least one of the following gratings—coupled-in grating 21, coupled-out grating 22, and folding grating—is provided on the outer surface of the outermost diffraction waveguide layer 20, an outer protective layer needs to be provided on the outside of the outermost diffraction waveguide layer 20 to protect the grating.

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

[0051] In a preferred embodiment, the sealing element 30 is an adhesive. During assembly, adhesive is first applied around the coupling grating 21 of the diffraction waveguide layer 20, wherein a reflective film 40 has been pre-formed on the diffraction waveguide layer 20, and the adhesive is partially applied to the reflective film 40. Then, the optomechanical system 10 or the fixing element 70 is bonded to the adhesive. This seals the gap between the optomechanical system 10 and the diffraction waveguide layer 20 and also fixes the optomechanical system 10. In other embodiments, when applying adhesive, it can also be applied to the corresponding positions of the optomechanical system 10 or the fixing element 70, so that the optomechanical system 10 or the fixing element 70 is adhered to the diffraction waveguide layer 20 and the reflective film 40.

[0052] The optical display module disclosed in this embodiment uses a reflective film to avoid direct contact between the sealing component and the total internal reflection propagation area of ​​the diffraction waveguide layer, thus ensuring light guiding efficiency. At the same time, it eliminates the need for an inner protective layer on the diffraction waveguide layer, reducing thickness and weight.

[0053] This second embodiment also discloses a head-mounted device, which includes the optical display module in the first embodiment. This head-mounted device can reduce the weight of the device while ensuring light guiding efficiency, which is beneficial for miniaturization 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 transmit and receive data from an external processing device via a signaling connection, which 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 standalone device, i.e., data processing is performed on the head-mounted device itself. The signaling connection can be configured to carry any kind of data, such as image data (e.g., still images and / or fully moving 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 smartphone, or other types of processing devices. The signaling 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 can communicate with one or more other external processing devices via a network, which may be, for example, a local area network (LAN), a wide area network (WAN), an intranet, a metropolitan area network (MAN), the Internet, or a combination thereof.

[0055] It should be noted that, as is understood, a complete augmented reality glasses system should also have other necessary basic components, but these other components are not the focus of this embodiment and are therefore not shown in the figures or described in detail in the specification. Moreover, these components are well-known technologies to those skilled in the art.

[0056] The specific embodiments of the present invention have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that modifications and improvements can be made to these embodiments without departing from the principles and spirit of the present invention as defined by the claims and their equivalents, and such modifications and improvements should also be within the protection scope of the present invention.

Claims

1. An optical display module, characterized in that, The optical display module includes an optical engine, a diffraction waveguide layer, a sealing element, and a reflective film. The optical engine is opposite to the diffraction waveguide layer and has a gap. The sealing element is disposed between the optical engine and the diffraction waveguide layer and is connected to both the optical engine 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 sealing element and the total internal reflection propagation region of the diffraction waveguide layer, such that the sealing element is spaced from the total internal reflection propagation region. The sealing element is an adhesive.

2. The optical display module according to claim 1, characterized in that, The optical display module also includes a fixing component, which is connected to the optomechanical system, and a sealing component is connected to the fixing component.

3. The optical display module according to claim 1, characterized in that, The reflective film may consist of a single layer or multiple layers.

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

5. The optical display module according to claim 3, characterized in that, The optical display module further includes a transparent film layer disposed on the surface of the diffraction waveguide layer near the optical engine; the reflective film is disposed on the outer surface of the transparent film layer near the optical engine, or the reflective film is disposed 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 multiple reflective regions, each with a different reflectivity.

7. The optical display module according to claim 1, characterized in that, The coupling grating of the diffraction waveguide layer is a reflection grating, and the coupling grating is disposed on the surface of the diffraction waveguide layer away from the optomechanism.

8. The optical display module according to claim 1, characterized in that, The coupling grating of the diffraction waveguide layer is a transmission grating, and the coupling grating is disposed on the surface of the diffraction waveguide layer near the optomechanism.

9. A head-mounted device, characterized in that, The head-mounted device includes the optical display module as described in any one of claims 1 to 8.

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