Optical module and near-to-eye display device

Abstract

The utility model provides an optical module and a near-to-eye display device, and relates to the technical field of optics. The optical module provided by the embodiment of the utility model comprises a display imaging module, a first polarization modulation module and a second polarization modulation module, the optical module further comprises a polarization modulation unit located in the first polarization modulation module and / or the second polarization modulation module. The polarization modulation unit comprises a first surface and a second surface which are connected. The second surface is located on the side, away from the center of the polarization modulation unit, of the first surface. The first surface is located on a propagation path of the display imaging light; the second surface comprises a first position and a second position, the first position and the second position are staggered in the first direction and the second direction, and the included angle between the straight line where the first position and the second position are located and the first surface is an obtuse angle. According to the optical module provided by the embodiment of the utility model, interference light beams are reduced, and the imaging definition is improved.

Description

Technical Field

[0001] The utility model relates to the field of optical technology, and in particular to an optical module and a near-eye display device. Background Art

[0002] The cut end surface of the polarizer in existing augmented reality glasses is exposed to the light irradiation area, causing part of the light to be emitted from the cut end surface of the polarizer, resulting in problems such as ghosting, double images and blue light. Utility Model Content

[0003] The embodiment of the utility model provides an optical module, which reduces interference light beams and improves the clarity of imaging.

[0004] According to one aspect of the present invention, an embodiment of the present invention provides an optical module, comprising: a display imaging module, a first polarization modulation module, and a second polarization modulation module, wherein the display imaging light emitted by the display imaging module is modulated by the first polarization modulation module and the second polarization modulation module in sequence before entering the human eye;

[0005] The optical module also includes a polarization modulation unit located in the first polarization modulation module and / or the second polarization modulation module; the polarization modulation unit includes a first surface and a second surface connected, and the second surface is located on the side of the first surface away from the center of the polarization modulation unit; the first surface is located on the propagation path of the display imaging light; the second surface includes a first position and a second position, and the first position and the second position are staggered in both the first direction and the second direction, and the angle between the straight line where the first position and the second position are located and the first surface is an obtuse angle; the first direction is the thickness direction of the polarization modulation unit, and the second direction intersects with the first direction.

[0006] Optionally, the first polarization modulation module includes a polarization reflection unit, which is located on a propagation path of the display imaging light and is configured to reflect the display imaging light to form a linearly polarized reflected light;

[0007] The second polarization modulation module includes a wave plate assembly, which is located on the adjustment path of the linearly polarized reflected light and is used to modulate the linearly polarized reflected light to form circularly polarized light;

[0008] The polarization modulation unit includes a polarization reflection unit and / or a wave plate component.

[0009] Optionally, the second surface comprises a flat surface.

[0010] Optionally, the incident angle of the display imaging light on the first surface is α, the refractive index of air is n1, the refractive index of the polarization modulation unit is n2, and the angle between the first surface and the second surface is β;

[0011] in,

[0012] Optionally, the second surface includes a plurality of step structures.

[0013] Optionally, the polarization modulation unit includes at least two polarization modulation film layers stacked together, and any polarization modulation film layer includes at least two step structures.

[0014] Optionally, the polarization modulation unit includes a first polarization modulation film layer and a second polarization modulation film layer that are stacked, and the thermal expansion coefficient of the first polarization modulation film layer is different from the thermal expansion coefficient of the second polarization modulation film layer;

[0015] In which, the number of step structures included in the first polarization modulation film layer is different from the number of step structures included in the second polarization modulation film layer, and / or the thickness of the step structure in the first polarization modulation film layer in the first direction is different from the thickness of the step structure in the second polarization modulation film layer in the first direction.

[0016] Optionally, along the first direction, a thickness d of the stepped structure satisfies 8 μm≤d≤20 μm.

[0017] Optionally, the second surface is provided with a microstructure, and the microstructure includes a plurality of protruding substructures and a plurality of recessed substructures.

[0018] Optionally, the optical module further includes a light absorption structure disposed on the second surface.

[0019] Optionally, the polarization modulation unit also includes a connected third surface and a fourth surface, the fourth surface is located on the side of the third surface away from the center of the polarization modulation unit; the third surface is parallel to the first surface, the fourth surface includes a third position and a fourth position, the third position and the fourth position are staggered in both the first direction and the second direction, and the angle between the straight line where the third position and the fourth position are located and the third surface is an obtuse angle.

[0020] Optionally, the first polarization modulation module further includes a polarization absorption unit, and / or the second polarization modulation module further includes a reflection adjustment unit, and the polarization reflection unit and the polarization absorption unit are sequentially arranged on the propagation path of the display imaging light and sequentially arranged on the propagation path of the linearly polarized light after modulation by the second polarization modulation module;

[0021] The transmission direction of the polarized light in the polarization absorption unit is the same as the transmission direction of the polarized light in the polarization reflection unit;

[0022] The wave plate assembly and the reflection adjustment unit are sequentially located on the adjustment path of the linearly polarized reflected light;

[0023] The polarization modulation unit further includes a polarization absorption unit and / or a reflection adjustment unit.

[0024] According to another aspect of the present invention, an embodiment of the present invention provides a near-eye display device, comprising the optical module provided by any embodiment of the present invention.

[0025] The optical module provided by the embodiment of the present utility model avoids the problem of light being incident from the first surface of the polarization modulation unit and then emitted from the second surface of the polarization modulation unit by changing the structure of the polarization modulation unit, so that most of the display imaging light can be modulated by the first polarization modulation module and the second polarization modulation module in sequence, reducing the intensity of the light not modulated by the polarization modulation unit, reducing the impact of the interfering light beam on the output image, improving the clarity of the imaging, and alleviating the problems of ghosting, double imaging and blue light in the output image.

[0026] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a structural schematic diagram of a polarization modulation unit in the prior art;

[0029] Figure 2 This is a structural diagram of an optical module provided by an embodiment of the present utility model;

[0030] Figure 3 This is a schematic structural diagram of a polarization modulation unit provided by an embodiment of the present utility model;

[0031] Figure 4 This is a schematic structural diagram of another optical module provided by an embodiment of the present utility model;

[0032] Figure 5 This is a schematic structural diagram of another polarization modulation unit provided by an embodiment of the present utility model;

[0033] Figure 6 This is a structural diagram of another polarization modulation unit provided by an embodiment of the present utility model;

[0034] Figure 7 yes Figure 6 A magnified view of the mid-step structure;

[0035] Figure 8 This is a structural diagram of another polarization modulation unit provided by an embodiment of the present utility model;

[0036] Figure 9 This is a structural diagram of another polarization modulation unit provided by an embodiment of the present utility model;

[0037] Figure 10 This is a structural diagram of another polarization modulation unit provided by an embodiment of the present utility model;

[0038] Figure 11 This is a structural diagram of another optical module provided by an embodiment of the present utility model;

[0039] Figure 12 It is a structural schematic diagram of a near-eye display device provided by an embodiment of the present utility model. DETAILED DESCRIPTION

[0040] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] Figure 1 This is a schematic diagram of the structure of the polarization modulation unit in the prior art, refer to Figure 1In the prior art, polarization modulators typically include a first surface 401' and a second surface 402', which are typically machined to be perpendicular to each other. The first surface 401' serves as the light incidence surface. Due to the limitations of the overall product layout, the entire first surface 401' is an optically effective area. Furthermore, to prevent the polarizer from being too large and impacting assembly, the polarizer is typically reduced in size. This results in the cut ends of the polarizer being exposed within the normal light effective area, specifically the ends of the first surface 401'. The majority of light incident on the polarization modulator enters through the first surface 401', is modulated by the polarization modulation unit, and then propagates to other optical systems for modulation, as shown by light S1' in the figure. However, because the cut ends of the polarization modulator are also exposed to light, a small amount of light incident on the polarization modulator enters through the ends of the first surface 401' and exits through the second surface 402', as shown by light S2' in the figure. This part of the light is not modulated by the polarization modulation unit, and due to refraction, the second surface 402' deflects the propagation direction of this part of the light, causing this part of the light to be output together with the normal light S1', thereby causing the image output by the optical system to have ghosting, double images and blue light problems.

[0043] Based on the above technical problems, an embodiment of the present invention provides an optical module, which improves the structure of the first surface and the second surface in the polarization modulation unit, changes the propagation direction of the original light incident on the end of the first surface, so that the interfering light cannot be output from the optical system, and eliminates the ghosting, ghosting and blue light problems caused by the interfering light in the optical system.

[0044] The above is the core concept of this technical solution. The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this utility model.

[0045] The embodiment of the utility model provides an optical module, Figure 2 This is a structural diagram of an optical module provided by an embodiment of the present utility model. Figure 3 This is a schematic diagram of the structure of the polarization modulation unit provided by the embodiment of the present utility model, combined with Figure 2 and Figure 3As shown, the optical module includes: a display imaging module 10, a first polarization modulation module 20 and a second polarization modulation module 30, and the display imaging light S1 emitted by the display imaging module 10 is modulated by the first polarization modulation module 20 and the second polarization modulation module 30 in sequence and then enters the human eye; the optical module also includes a polarization modulation unit 40 located in the first polarization modulation module 20 and / or the second polarization modulation module 30; the polarization modulation unit includes a first surface 401 and a second surface 402 connected, and the second surface 402 is located on the side of the first surface 401 away from the center of the polarization modulation unit 40; the first surface 401 is located on the propagation path of the display imaging light S1; the second surface 402 includes a first position 4021 and a second position 4022, and the first position 4021 and the second position 4022 are staggered in both the first direction X and the second direction Y, and the angle between the straight line where the first position 4021 and the second position 4022 are located and the first surface 401 is an obtuse angle; the first direction X is the thickness direction of the polarization modulation unit 40, and the second direction Y intersects with the first direction X.

[0046] refer to Figure 2 The imaging light S1 emitted by the imaging unit 10 is reflected by the first polarization modulation module 20 to become a linearly polarized reflected light S2. The linearly polarized reflected light S2 is reflected by the second polarization modulation module 30 and modulated again by the first polarization modulation module 20 to become a linearly polarized light S3. The linearly polarized reflected light S2 then enters the human eye and forms an image at the human eye. The polarization modulation unit 40 in the first polarization modulation module 20 and / or the second polarization modulation module 30 can be structured as follows: Figure 3 As shown, the first position 4021 and the second position 4022 are located on the second surface 402. The straight line where the first position 4021 and the second position 4022 are located is neither parallel to the first direction X nor parallel to the second direction Y. Therefore, the second surface 402 is neither a coplanar surface with the first surface 401 nor a surface perpendicular to the first surface 401. The angle between the straight line where the first position 4021 and the second position 4022 are located on the second surface 402 and the first surface 401 is an obtuse angle. It can be understood that the second surface 4022 is an inclined surface or has a tendency to be inclined. The side close to the first surface 401 is obtuse. Figure 3 The Y direction has a smaller extension length, and the side away from the first surface 401 has a smaller extension length. Figure 3The Y direction has a larger extension length; or in other words, for the entire polarization modulation unit 40, the side close to the first surface 401 has a larger coverage area, and the side away from the first surface 401 has a smaller coverage area. By adjusting the structure of the second surface 402, part of the light that would originally be incident on the end of the first surface 401 and emitted from the second surface 402 cannot be incident on the polarization modulation unit 40. This part of the light is directly emitted to the external environment, will not participate in the subsequent light adjustment, and will not eventually enter the human eye to form interfering light. For example, compared with reference Figure 1 and Figure 3 As shown, the first imaging light S101, Figure 1 In the polarization adjustment unit 40 shown, light enters the polarization adjustment unit 40 from the first surface 401 ′ and then exits from the second surface 402 ′. Figure 1 In the prior art solution shown in FIG. 4 , in this embodiment, the angle formed between the second surface 402 and the first surface 401 is an obtuse angle, and the first imaging light S101 does not enter the polarization modulation unit 40. This greatly reduces the probability that light enters the first surface 401 and exits the second surface 402. In other words, this structure of the polarization modulation unit 40 prevents some light that has not been modulated by the polarization modulation unit 40 from entering the subsequent optical system, thereby reducing the problems of ghosting, double images, and blue light caused by interfering light.

[0047] To sum up, the optical module provided by the embodiment of the present invention avoids the problem of light being incident from the first surface of the polarization modulation unit and then emitted from the second surface of the polarization modulation unit by changing the structure of the polarization modulation unit, so that most of the display imaging light can be modulated by the first polarization modulation module and the second polarization modulation module in sequence, reducing the intensity of the light that is not modulated by the polarization modulation unit, reducing the impact of the interfering light beam on the output image, improving the clarity of the imaging, and alleviating the problems of ghosting, double imaging and blue light in the output image.

[0048] Figure 4 This is a schematic diagram of the structure of another optical module provided by the embodiment of the present invention, referring to Figure 4 The first polarization modulation module 20 includes a polarization reflection unit 201, which is located on the propagation path of the display imaging light S1 and is used to reflect the display imaging light S1 to form a linearly polarized reflected light S2; the second polarization modulation module 30 includes a wave plate assembly 301, which is located on the adjustment path of the linearly polarized reflected light S2 and is used to modulate the linearly polarized reflected light S2 to form a circularly polarized light; the polarization modulation unit 40 includes the polarization reflection unit 201 and / or the wave plate assembly 301.

[0049] refer to Figure 4, the display imaging light S1 is reflected by the polarization reflection unit 201 to form a linearly polarized reflected light S2, and the wave plate assembly 301 modulates the polarized reflected light S2 into circularly polarized light. The display imaging light S1 emitted by the display imaging module 10 can be any linearly polarized light in actual applications, such as s-polarized light or p-polarized light. The polarization reflection unit 201 exhibits total reflection or high reflectivity characteristics for linearly polarized light with the same polarization direction as the display imaging light S1, that is, the polarization reflection unit 2 can reflect most of the display imaging light S1. For example, the polarization reflection unit 201 can exhibit total reflection or high reflectivity characteristics for s-polarized light; or, the polarization reflection unit 201 can exhibit total reflection or high reflectivity characteristics for p-polarized light. It should be noted that the specific values ​​of the high reflectivity and high transmittance mentioned above depend on the performance of the polarized reflection unit 201 itself. For example, a polarized reflection unit 201 with better performance can achieve a reflectivity of 99% for linearly polarized light with the same polarization direction as the display imaging light S1. The embodiment of the present utility model does not specifically limit the performance of the polarized reflection unit 201.

[0050] Furthermore, the wave plate assembly 301 includes a quarter wave plate, the fast axis and slow axis of the quarter wave plate are at an angle of 45 degrees to the polarization direction of the linearly polarized reflected light S2. The component of the linearly polarized reflected light S2 whose polarization direction is parallel to the fast axis of the quarter wave plate propagates faster in the quarter wave plate, and this component is the first component; while the component of the polarization direction parallel to the slow axis of the quarter wave plate propagates slower in the quarter wave plate, and this component is the second component. In this way, after the linearly polarized reflected light S2 passes through the quarter wave plate, there is a The phase difference is 0.01, and the linearly polarized reflected light S2 becomes circularly polarized light.

[0051] Combine Figure 1 、 Figure 3 and Figure 4 As shown, the polarization modulation unit 40 may include a polarization reflection unit 201. If the structure of the polarization reflection unit 201 is as shown in FIG. Figure 1 As shown, when the display imaging light S1 is incident on the polarized reflection unit 201, part of the display imaging light S1 will be emitted from the end of the polarized reflection unit 201. The display imaging light S1 emitted from the end cannot be reflected to the wave plate assembly 301. This part of the light will cause the optical module to output an image with ghosting, double images, and blue light. Figure 3As shown, part of the light that would have been incident on the end of the first surface 401 of the polarized reflection unit 201 and emitted from the second surface 402 of the polarized reflection unit 201 cannot be incident on the polarized reflection unit 201. This part of the light is directly emitted to the external environment and will not participate in subsequent light adjustments. Ultimately, it will not enter the human eye to form interfering light, thereby reducing the problems of ghosting, double imaging and blue light in the output image of the optical module.

[0052] Furthermore, the polarization modulation unit 40 may include a wave plate assembly 301. If the structure of the wave plate assembly 301 is as follows: Figure 1 As shown, part of the linearly polarized reflected light S2 will be emitted from the end of the wave plate assembly 301. This part of the light is not fully modulated by the wave plate assembly 301, and the output from the optical module will cause the output image to have ghosting, double images and blue light problems. Figure 3 As shown, part of the light that would have been incident on the end of the first surface 401 of the wave plate assembly 301 and emitted from the second surface 402 of the wave plate assembly 301 cannot be incident on the wave plate assembly 301. This part of the light is directly emitted to the external environment and will not participate in the subsequent light adjustment. Ultimately, it will not enter the human eye to form interfering light, thereby reducing the problems of ghosting, double imaging and blue light in the output image of the optical module.

[0053] Optionally, the second surface 402 comprises a flat surface.

[0054] refer to Figure 3 The straight line formed by the first position 4021 and the second position 4022 on the second surface 402 is a straight line within the second surface 402, and the angle formed between the second surface 402 and the first surface 401 is an obtuse angle. This structure of the polarization modulation unit 40 prevents some light that would otherwise be incident on the first surface 401 and emitted from the second surface 402 from entering the polarization modulation unit 40, thereby reducing interfering light and alleviating issues such as ghosting, double images, and blue light.

[0055] Optionally, the angle formed by the first surface 401 and the first surface 402 ranges from 105° to 165°. Setting the angle formed by the first surface 401 and the first surface 402 to be at least greater than 105° can prevent excessive light from entering the first surface 401 and then exiting the second surface 402. Furthermore, the angle formed by the first surface 401 and the first surface 402 is less than 165° to prevent the second surface 402 from being too long. This ensures that the polarization modulation unit 40 has a smaller size and avoids issues with the polarization modulation unit 40 being too large and affecting assembly.

[0056] Figure 5 This is a schematic diagram of the structure of another polarization modulation unit provided by an embodiment of the present invention, referring to Figure 5Optionally, the incident angle of the imaging light S1 on the first surface 401 is α, the refractive index of air is n1, the refractive index of the polarization modulation unit is n2, and the angle between the first surface 401 and the second surface 402 is β; wherein,

[0057] For the display imaging light S1, we have:

[0058] n1*sinα=n2*sinγ,

[0059] Wherein, γ is the angle of incidence of the imaging light S1 on the first surface 401. According to the above formula, γ is:

[0060]

[0061] The angle between the emitted light of imaging light S1 on the first surface 401 and the first surface 401 is Therefore, the included angle between the first surface 401 and the second surface 402 is set to be greater than the included angle between the light emitted from the first surface 401 by the imaging light S1 and the first surface 401, that is, the included angle between the first surface 401 and the second surface 402 is set to β to satisfy This ensures that the display imaging light S1 cannot be emitted from the second surface 402, thereby eliminating the ghosting, double imaging and blue light problems caused by interfering light.

[0062] Figure 6 This is a structural diagram of another polarization modulation unit provided by an embodiment of the present utility model. Figure 7 yes Figure 6 The enlarged view of the mid-step structure, combined with Figure 6 and Figure 7 As shown, the second surface 402 includes a plurality of step structures. The second surface 402 should generally include at least two step structures, but the embodiment of the present invention does not impose a specific restriction on the number of step layers of the step structure. The step structure can continuously change the propagation direction of the light incident into the step structure. After multiple refractions, the propagation direction of the light incident into the step structure will turn to a direction close to the center of the polarization modulation unit 40, so that the light incident into the step structure is emitted from the third surface 403. At the same time, after the interfering light is incident into the step structure, the interfering light will be scattered by multiple step interfaces, and its energy will be attenuated multiple times. Therefore, the problems of ghosting, double images and blue light caused by the emission of the interfering light will also be alleviated.

[0063] Optionally, Figure 8 This is a schematic diagram of the structure of another polarization modulation unit provided by an embodiment of the present invention, referring to Figure 8The polarization modulation unit 40 includes at least two stacked polarization modulation film layers, and any polarization modulation film layer includes at least two step structures.

[0064] Specifically, the polarization modulation unit 40 may include multiple film layers, such as a polyvinyl alcohol film layer, a triacetyl cellulose film layer, and a pressure-sensitive adhesive film layer. Because the different film layers are made of different materials, they experience different changes in temperature when the temperature changes. Therefore, each polarization modulation film layer is configured to include at least two stepped structures. This ensures that each polarization modulation film layer can modulate incident light, such as modulating the light propagation direction and light energy. This can alleviate issues such as ghosting, double vision, and blue light caused by interfering light exiting the film layer.

[0065] refer to Figure 8 Optionally, the polarization modulation unit 40 includes a first polarization modulation film layer 41 and a second polarization modulation film 42 that are stacked, and the thermal expansion coefficient of the first polarization modulation film layer 41 is different from the thermal expansion coefficient of the second polarization modulation film layer 42; wherein, the number of step structures included in the first polarization modulation film layer 41 is different from the number of step structures included in the second polarization modulation film layer 42, and / or the thickness of the step structure in the first polarization modulation film layer 41 in the first direction is different from the thickness of the step structure in the second polarization modulation film layer 42 in the first direction X.

[0066] As mentioned above, different polarizing film layers have different thermal parameters due to differences in materials, such as thermal expansion parameters or thermal contraction parameters. Different thermal parameters cause different film layers to expand or contract differently when the temperature changes, resulting in different modulation effects on light. Figure 8Taking the polarization modulation unit 40 shown as an example, the polarization modulation unit 40 includes a first polarization modulation film layer 41 and a second polarization modulation film layer 42, which are stacked. Because the thermal expansion coefficients of the first polarization modulation film layer 41 and the second polarization modulation film layer 42 differ, the number of step structures included in the first polarization modulation film layer 41 is different from the number of step structures included in the second polarization modulation film layer 42, and / or the thickness of the step structures in the first direction X of the first polarization modulation film layer 41 is different from the thickness of the step structures in the second polarization modulation film layer 42. This ensures that both the first polarization modulation film layer 41 and the second polarization modulation film layer 42 can achieve a good light modulation effect, and also ensures that the overall volume of the polarization adjustment unit 40 meets the overall assembly requirements of the optical module. For example, if the thermal expansion coefficient of the second polarization modulation film layer 42 is smaller than that of the first polarization modulation film layer 41, the first polarization modulation film layer 41 will expand more when thermally heated, while the second polarization modulation film layer 42 will expand less when thermally heated. To ensure that light modulated by the first polarization modulation film layer 41 can continue to be modulated by the second polarization modulation film layer 42, the second polarization modulation film layer 42 can be configured to have a larger number of steps, or the thickness of the mid-step structure of the second polarization modulation film layer 42 in the first direction X can be configured to be thicker. This ensures that each polarization modulation film layer can modulate the light incident thereon, thereby reducing the problems of ghosting, double images, and blue light caused by the emission of interfering light. For example, if the thermal expansion coefficient of the first polarization modulation film layer 41 is greater than that of the second polarization modulation film layer 42, the first polarization modulation film layer 41 will expand more significantly when heated. Therefore, the number of steps in the first polarization modulation film layer 41 should be smaller to prevent the first polarization modulation film layer 41 from expanding too much when heated, thereby damaging the structure of the polarization modulation unit 40. Similarly, if the thermal expansion coefficient of the first polarization modulation film layer 41 is greater than the thermal expansion coefficient of the second polarization modulation film layer 42, the thickness of the mid-step structure of the first polarization modulation film layer 41 in the first direction X should be thinner to prevent the first polarization modulation film layer 41 from expanding too much due to heat, thereby damaging the structure of the polarization modulation unit 40.

[0067] It should be noted that this rule is also applicable to the case where the polarization modulation unit 40 includes three or more film layers, which will not be described in detail here.

[0068] Optionally, along the first direction X, the thickness d of the step structure satisfies 8 μm ≤ d ≤ 20 μm. If the thickness of the step structure is too small, the step structure will be too difficult to manufacture, its processing cost will increase, and the step structure will be more susceptible to damage. If the thickness of the step structure is too large, the step structure will expand excessively when heated, and the step structure may damage the structure of the polarization modulation unit 40 after heating. Therefore, the thickness d of the step structure along the first direction X should satisfy 8 μm ≤ d ≤ 20 μm, so that the step structure can function normally, is easy to manufacture, and has a stable structure.

[0069] Figure 9 This is a schematic diagram of the structure of another polarization modulation unit provided by an embodiment of the present invention, referring to Figure 9 The second surface 402 is provided with a microstructure comprising a plurality of raised substructures and a plurality of recessed substructures. The raised and recessed substructures within the microstructure may be arranged regularly or irregularly, and the sizes of the raised and recessed substructures may be significantly smaller than those of the aforementioned stepped structures. The microstructure scatters incident light, preventing light incident on the second surface 402 from being output from the optical module. The microstructure eliminates interfering light to a certain extent, alleviating issues such as ghosting, ghosting, and blue light.

[0070] It should be noted that if the polarization modulation unit 40 has Figure 6 In the step structure shown, the microstructure may extend along the first direction X and the second direction Y on the surface of the step structure.

[0071] Optionally, the optical module further includes a light-absorbing structure disposed on the second surface 402. The light-absorbing structure absorbs light incident on the second surface 402, thereby preventing the light incident on the second surface 402 from being output from the optical module. The light-absorbing structure eliminates interfering light to a certain extent, thereby alleviating issues such as ghosting, ghosting, and blue light.

[0072] Figure 10 This is a schematic diagram of the structure of another polarization modulation unit provided by an embodiment of the present invention, referring to Figure 10 The polarization modulation unit 40 also includes a third surface 403 and a fourth surface 404 connected to each other, and the fourth surface 404 is located on a side of the third surface 403 away from the center of the polarization modulation unit 40; the third surface 403 is parallel to the first surface 401, and the fourth surface 404 includes a third position 4041 and a fourth position 4042, and the third position 4041 and the fourth position 4042 are staggered in both the first direction X and the second direction Y, and the angle between the straight line where the third position 4041 and the fourth position 4042 are located and the third surface 403 is an obtuse angle.

[0073] refer to Figure 10The display imaging light S1 emitted from the fourth surface 404 is refracted by the fourth surface 404, and the propagation direction of the display imaging light S1 will be offset in the direction away from the center of the polarization modulation unit 40, so that the display imaging light S1 emitted from the fourth surface 404 will not be incident on the subsequent optical system, thereby avoiding interference light output from the optical module and reducing ghosting, double imaging and blue light problems.

[0074] Figure 11 This is a schematic diagram of the structure of another optical module provided by the embodiment of the present invention, referring to Figure 11 The first polarization modulation module 20 also includes a polarization absorption unit 202, and / or the second polarization modulation module 30 also includes a reflection adjustment unit 302. The polarization reflection unit 201 and the polarization absorption unit 202 are sequentially arranged on the propagation path of the display imaging light S1, and are sequentially arranged on the propagation path of the linearly polarized light S3 formed after modulation by the second polarization modulation module 30; the transmission direction of the polarized light in the polarization absorption unit 202 is the same as the transmission direction of the polarized light in the polarization reflection unit 201; the wave plate assembly 301 and the reflection adjustment unit 302 are sequentially located on the adjustment path of the linearly polarized reflected light S2; the polarization modulation unit 40 also includes the polarization absorption unit 202 and / or the reflection adjustment unit 302.

[0075] refer to Figure 11 The polarization direction of the linearly polarized light that can be transmitted through the polarization absorption unit 202 is the transmission polarization direction of the polarization absorption unit 202, while the linearly polarized light with a polarization direction perpendicular to the transmission polarization direction of the polarization absorption unit 202 will be absorbed by the polarization absorption unit 202. The polarization absorption unit 202 is located in a direction away from the wave plate assembly 301 of the polarization reflection unit 201. The polarization direction of the linearly polarized light that can be transmitted through the polarization absorption unit 202 and the linearly polarized light that can be transmitted through the polarization reflection unit 201 are the same. Assuming that the display imaging beam S1 is s-polarized light, the polarization reflection unit 201 can reflect the s-polarized light, and the polarization absorption unit 202 can absorb the s-polarized light that has been transmitted through the polarization reflection unit 201. The s-polarized light reflected by the polarized reflection unit 201 then forms a linearly polarized reflected light S2. The linearly polarized reflected light S2 passes through the wave plate assembly 301 and becomes circularly polarized light. The circularly polarized light is reflected by the reflection adjustment unit 302 and passes through the wave plate assembly 301 again, and the circularly polarized light becomes a linearly polarized light S3. The polarization direction of the linearly polarized light S3 is perpendicular to the polarization direction of the display imaging light S1. The linearly polarized light S3 is p-polarized light. The linearly polarized light S3 can pass through the polarized reflection unit 201 and the polarization absorption unit 202. Finally, the linearly polarized light S3 is emitted from the optical module.

[0076] Furthermore, the polarization modulation unit 40 may include a polarization absorption unit 202. If the structure of the polarization absorption unit 202 is as follows: Figure 1As shown, the polarization absorption unit 202 can absorb incident p-polarized light. However, some p-polarized light will be emitted from the end face of the polarization absorption unit 202 and thus not absorbed by the polarization absorption unit 202. This light will cause the quality of the output image to deteriorate after being output. Therefore, setting the structure of the polarization absorption unit 202 to any of the structures of the polarization modulation unit 40 provided in the embodiments of the present invention can prevent the output of p-polarized light that is not absorbed by the polarization absorption unit 202, thereby improving the quality of the output image.

[0077] The polarization modulation unit 40 may include a reflection adjustment unit 302. For the reflection adjustment unit 302, if the structure of the reflection adjustment unit 302 is as follows: Figure 1 As shown, the light emitted from the end face of the reflection adjustment unit 302 cannot be reflected by the reflection adjustment unit 302, and this part of the light cannot be modulated again by the wave plate assembly 301. If the structure of the reflection adjustment unit 302 is any of the structures of the polarization modulation unit 40 provided in the embodiments of the present invention, the light is prevented from being emitted from the end face of the reflection adjustment unit 302, thereby improving the quality of the output image.

[0078] Based on the same concept, an embodiment of the present invention provides a near-eye display device, including the optical module provided by any embodiment of the present invention. Figure 12 This is a schematic structural diagram of a near-eye display device provided by an embodiment of the present invention. Figure 12 As shown, the near-eye display device 1 can be an augmented reality (AR) display device, a virtual reality (VR) display device, an electronic view finder (EVF), a mobile phone, a computer, or a television, and other electronic display devices, and the embodiments of the present invention are not limited to this. In addition, the near-eye display device provided by the embodiments of the present invention includes the optical module provided by any embodiment of the present invention, and has the technical effects described in the above optical modules, which will not be repeated here.

[0079] The above specific embodiments do not limit the scope of protection of this utility model. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model shall be included within the scope of protection of this utility model.

Claims

1. An optical module, characterized in that: include: a display imaging module, a first polarization modulation module, and a second polarization modulation module, wherein the display imaging light emitted by the display imaging module is modulated by the first polarization modulation module and the second polarization modulation module in sequence before entering the human eye; The optical module also includes a polarization modulation unit located in the first polarization modulation module and / or the second polarization modulation module; the polarization modulation unit includes a first surface and a second surface connected, and the second surface is located on the side of the first surface away from the center of the polarization modulation unit; the first surface is located on the propagation path of the display imaging light; the second surface includes a first position and a second position, and the first position and the second position are staggered in both the first direction and the second direction, and the angle between the straight line where the first position and the second position are located and the first surface is an obtuse angle; the first direction is the thickness direction of the polarization modulation unit, and the second direction intersects with the first direction.

2. The optical module according to claim 1, wherein: The first polarization modulation module includes a polarization reflection unit, which is located on the propagation path of the display imaging light and is used to reflect the display imaging light to form linearly polarized reflected light; The second polarization modulation module includes a wave plate component, which is located on the adjustment path of the linearly polarized reflected light and is used to modulate the linearly polarized reflected light to form circularly polarized light; The polarization modulation unit includes the polarization reflection unit and / or the wave plate assembly.

3. The optical module according to claim 1, wherein: The second surface includes a flat surface.

4. The optical module according to claim 3, wherein: The incident angle of the display imaging light on the first surface is α, the refractive index of air is n1, the refractive index of the polarization modulation unit is n2, and the angle between the first surface and the second surface is β; in, 5. The optical module according to claim 1, wherein: The second surface includes a plurality of step structures.

6. The optical module according to claim 5, wherein: The polarization modulation unit includes at least two polarization modulation film layers stacked together, and any of the polarization modulation film layers includes at least two of the step structures.

7. The optical module according to claim 6, wherein: The polarization modulation unit includes a first polarization modulation film layer and a second polarization modulation film layer that are stacked, and the thermal expansion coefficient of the first polarization modulation film layer is different from the thermal expansion coefficient of the second polarization modulation film layer; In which, the number of the step structures included in the first polarization modulation film layer is different from the number of the step structures included in the second polarization modulation film layer, and / or the thickness of the step structures in the first direction in the first polarization modulation film layer is different from the thickness of the step structures in the second polarization modulation film layer in the first direction.

8. The optical module according to claim 5, wherein: Along the first direction, a thickness d of the stepped structure satisfies 8 μm≤d≤20 μm.

9. The optical module according to claim 1, wherein: The second surface is provided with a microstructure, and the microstructure includes a plurality of protruding substructures and a plurality of recessed substructures.

10. The optical module according to claim 1, wherein: The optical module further includes a light absorption structure disposed on the second surface.

11. The optical module according to claim 1, wherein: The polarization modulation unit also includes a third surface and a fourth surface that are connected, and the fourth surface is located on the side of the third surface away from the center of the polarization modulation unit; the third surface is parallel to the first surface, and the fourth surface includes a third position and a fourth position, and the third position and the fourth position are staggered in both the first direction and the second direction, and the angle between the straight line where the third position and the fourth position are located and the third surface is an obtuse angle.

12. The optical module according to claim 2, wherein: The first polarization modulation module further includes a polarization absorption unit, and / or the second polarization modulation module further includes a reflection adjustment unit, the polarization reflection unit and the polarization absorption unit are sequentially arranged on the propagation path of the display imaging light and are sequentially arranged on the propagation path of the linearly polarized light modulated by the second polarization modulation module; The wave plate assembly and the reflection adjustment unit are sequentially arranged on the adjustment path of the linearly polarized reflected light; The transmission direction of the polarized light in the polarization absorbing unit is the same as the transmission direction of the polarized light in the polarization reflecting unit; The polarization modulation unit further includes the polarization absorption unit and / or the reflection adjustment unit.

13. A near-eye display device, characterized in that: The optical module comprises the optical module according to any one of claims 1 to 12.

Images