Lens module

Abstract

The utility model relates to a lens module which comprises an optical waveguide, a first prescription lens located on the human eye side of a substrate and a second prescription lens located on the environment side of the substrate, the optical waveguide comprises an optical waveguide, a filling layer and a low-folding layer, a diffraction grating is arranged on the optical waveguide, the diffraction grating is filled with the filling layer, and the low-folding layer covers the filling layer. Wherein the refractive index of the low-folding layer is different from that of the filling and leveling layer, the viscosity of the filling and leveling layer is smaller than that of the low-folding layer, and the refractive indexes of the filling and leveling layer, the low-folding layer, the first prescription lens and the second prescription lens are respectively smaller than that of the substrate. Therefore, the formed lens module has the characteristics of low ghost image, light weight and thinness, the diffraction grating of the optical waveguide cannot be interfered, and a better imaging effect is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to AR glasses technical field, in particular to a lens module. BACKGROUND

[0002] AR lens module is one of the core components of AR glasses. Mainly by diffraction optical waveguide as the base, set prescription lens, color changing piece, eye movement tracking assembly on the base, through 0.05~0.2mm thickness optical cement will be bonded with them and optical waveguide. Prescription lens is generally located on both sides of optical waveguide, it can not only satisfy the use of different vision people, but also protect the pollution and damage of external impurities, particles to diffraction optical waveguide. Therefore, prescription lens can also replace the two layer cover plate glass on the surface of the current diffraction optical waveguide, so that the thickness of single layer diffraction optical waveguide can be reduced by about 0.8mm.

[0003] Prescription lens usually adopts injection molding or glue filling forming, when prescription lens is formed on the side of optical waveguide provided with diffraction grating, ghost image is easy to produce in the picture, therefore, a low refractive layer needs to be arranged between optical waveguide and prescription lens, but there are hollow particles in part of the ultra-low refractive material, which is easy to interfere with the light emission of the diffraction grating of optical waveguide, thereby affecting imaging. SUMMARY

[0004] Based on the existing diffraction optical waveguide glasses, when prescription lens is directly injection molded on optical waveguide, there are problems of ghost image and interference with the light emission of diffraction grating of optical waveguide, it is necessary to provide a lens module.

[0005] A lens module comprises:

[0006] An optical waveguide comprises a substrate, a filling layer and a low refractive layer, the substrate is provided with a diffraction grating, the filling layer is filled in the diffraction grating, the low refractive layer is covered on the filling layer, the refractive index of the low refractive layer is different from the refractive index of the filling layer, and the viscosity of the filling layer is less than the viscosity of the low refractive layer;

[0007] A first prescription lens is attached to the eye side of the optical waveguide; and

[0008] A second prescription lens is attached to the environment side of the optical waveguide.

[0009] The refractive index of the filling layer, the low refractive layer, the first prescription lens and the second prescription lens is less than the refractive index of the substrate respectively.

[0010] In this way, the diffraction grating of the optical waveguide is filled by the filling layer with a low refractive index, so that the hollow particles of the low refractive layer cannot enter the diffraction grating, and the light can be normally emitted from the diffraction grating. Therefore, the first prescription lens and the second prescription lens can be directly formed on both sides of the optical waveguide by the glue filling process without additional adhesive layers, so that the thickness of the lens module can be further reduced. Specifically, the thickness of the entire lens module can be reduced by 0.1mm-0.4mm by removing the two adhesive layers. During the entire production process, since the prescription lens is integrally formed on the optical waveguide, the two alignment and stacking operations are also omitted, so that the production cycle of the entire lens module can be reduced, which is beneficial to reduce the production cost and improve the overall yield of assembly.

[0011] In some embodiments of the present application, the refractive index of the filling layer ranges from 1.0 to 1.4, and the refractive index of the first prescription lens is less than or equal to 1.75.

[0012] In this way, the light can be transmitted in the optical waveguide, and the ghost image caused by refraction of the light on both sides of the optical waveguide can be avoided.

[0013] In some embodiments of the present application, the first prescription lens has optical power; and / or

[0014] The second prescription lens has optical power.

[0015] In this way, the lens module produced can match the myopic or hyperopic population, which is beneficial to realize customized lenses.

[0016] In some embodiments of the present application, the second prescription lens has a first covering portion attached to the environmental side of the optical waveguide and a second covering portion attached to the peripheral side of the optical waveguide.

[0017] In this way, the second prescription lens wraps the optical waveguide during forming, which is beneficial to improve the structural stability of the lens module.

[0018] In some embodiments of the present application, the optical power of the first covering portion is positive, and the distance from the side of the first covering portion away from the optical waveguide to the environmental side of the optical waveguide is greater than or equal to 0.1mm.

[0019] In this way, under the existing technical conditions, the material for glue filling forming can smoothly flow into the outer peripheral surface of the optical waveguide, ensuring the forming of the second prescription lens.

[0020] In some embodiments of the present application, the distance between the side of the second covering portion away from the optical waveguide and the peripheral side of the optical waveguide is greater than or equal to 0.1mm.

[0021] In this way, the radial thickness provides an operation space for subsequent polishing or cutting of the lens module.

[0022] In some embodiments of the present application, the eye side of the optical waveguide has a coupling-in surface, and the first prescription lens has a first accommodation step corresponding to the coupling-in surface.

[0023] In this way, the exit end of the optical engine can extend into the first accommodation step, which helps to reduce the size of the assembled lens module. On the other hand, the distance between the exit end of the optical engine and the coupling-in surface is smaller, which can reduce the stray light entering the optical waveguide, thereby improving the image quality. Furthermore, the structure of the first accommodation step reduces the volume and mass of the first prescription lens, and also reduces the mass of the entire lens module and even the entire smart glasses, which helps to improve the user's wearing experience.

[0024] In some embodiments of the present application, the size of the first prescription lens is smaller than the size of the optical waveguide to form a first inwardly recessed step.

[0025] In this way, the first inwardly recessed step can be used for the support assembly of the smart glasses to extend into, so as to further reduce the thickness of the smart glasses, thereby further realizing the slimming of the smart glasses.

[0026] In some embodiments of the present application, the edge of the second prescription lens is provided with a second accommodation step.

[0027] In this way, the thickness of the lens module at the edge is further reduced, and the second accommodation step is used to accommodate the support component that clamps the lens module in the smart glasses. In this way, the thickness of the smart glasses is further reduced, which conforms to the trend of miniaturization of smart glasses and improves the portability of smart glasses.

[0028] In some embodiments of the present application, the size of the second prescription lens is smaller than the size of the optical waveguide to form a second inwardly recessed step.

[0029] In this way, the size can also be reduced. It can be understood that the second inwardly recessed step can be directly generated by a mold when the second prescription lens is formed, or can be processed by a CNC process. The selection of the specific processing method is determined by the precision and difficulty of the process. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 FIG. 1 is an exploded structural schematic view of a lens module in an embodiment of the present application;

[0031] Figure 2 FIG. 3 is a structural schematic view of a substrate in a diffraction grating in FIG. 1; Figure 1

[0032] Figure 3 FIG. 5 is a structural schematic view of a lens module in a mold in an embodiment of the present application; and

[0033] ​Figure 4 A structure diagram of a semi-finished product A of a lens module provided in an embodiment of the present application;

[0034] Figure 5 A structure diagram of a semi-finished product B of a lens module provided in an embodiment of the present application;

[0035] Figure 6 A structure diagram of an edge of a lens module provided in Example 1 of the present application;

[0036] Figure 7 A structure diagram of an edge of a lens module provided in Example 2 of the present application;

[0037] Figure 8 A structure diagram of an edge of a lens module provided in Example 3 of the present application;

[0038] Figure 9 A structure diagram of an edge of a lens module provided in Example 4 of the present application.

[0039] Reference signs:

[0040] 1, substrate; 2, diffraction grating; 3, filling layer; 4, low-refractive layer; 5, optical waveguide; 6, second prescribed lens; 7, first prescribed lens; 8-a, first accommodation step; 8-b, first retracted step; 9-a, second accommodation step; 9-b, second retracted step. DETAILED DESCRIPTION

[0041] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without using these specific details. In other instances, well-known methods have not been described in detail in order to avoid unnecessarily obscuring the present application. Therefore, the specific embodiments disclosed below are not intended to limit the scope of the present application, but merely to exemplify various embodiments of the present application.

[0042] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of the indicated technical features. Thus, features defined with "first", "second" or "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0044] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0046] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on another element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and are not the only embodiment.

[0047] The AR lens module is one of the core components of the AR glasses. It is mainly composed of a diffractive optical waveguide as a substrate, a prescription lens, a color-changing sheet, an eye movement tracking component, etc. on the substrate, and they are bonded with the optical waveguide through 0.05-0.2mm thick optical adhesive. The prescription lens is generally located on both sides of the optical waveguide, which can not only meet the needs of people with different vision, but also protect the outside impurities and particles from polluting and damaging the diffractive optical waveguide. Therefore, the prescription lens can also replace the two layers of cover glass on the surface of the current diffractive optical waveguide, so that the thickness of the single-layer diffractive optical waveguide can be reduced by at least about 0.8mm.

[0048] The prescription lens is generally formed by injection molding or glue filling, when the prescription lens is formed on the side of the optical waveguide provided with the diffraction grating, ghost images are easily generated in the picture, and thus a low-refractive layer needs to be arranged between the optical waveguide and the prescription lens, but hollow particles exist in some ultra-low-refractive materials, which easily interfere with the light emission at the diffraction grating of the optical waveguide, thereby affecting the imaging.

[0049] Therefore, it is necessary to provide a lens module with less ghost image and the diffraction grating 2 not interfered with when emitting light.

[0050] Please refer to Figure 1 and Figure 2 , Figure 1 the explosion structure schematic diagram of the lens module in an embodiment of the present application, Figure 2 the structure schematic diagram of the lens module at the diffraction grating 2 is shown in Figure 1 . In the embodiment, the lens module comprises an optical waveguide 5, a first prescription lens 7 located on the human eye side of the optical waveguide 5, and a second prescription lens 6 located on the environment side of the optical waveguide 5, the optical waveguide 5 comprises a substrate 1, a filling layer 3, and a low-refractive layer 4, the substrate 1 is provided with a diffraction grating 2, the filling layer 3 is filled in the diffraction grating 2, and the low-refractive layer 4 is arranged on the filling layer 3, wherein the refractive index of the low-refractive layer 4 is different from the refractive index of the filling layer 3, and the viscosity of the filling layer 3 is less than the viscosity of the low-refractive layer 4, and wherein the refractive indexes of the filling layer 3, the low-refractive layer 4, the first prescription lens 7, and the second prescription lens 6 are respectively less than the refractive index of the substrate 1. The diffraction grating 2 of the optical waveguide 5 is filled by the filling layer 3 with low refractive index, so that the hollow particles of the low-refractive layer 4 cannot enter the diffraction grating 2, and the light emission at the diffraction grating 2 is ensured to be normal, and thus the first prescription lens 7 and the second prescription lens 6 can be formed on both sides of the optical waveguide 5 by the glue filling process in the present application, without the need of an additional glue layer, and thus the thickness of the lens module can be further reduced, and specifically, the thickness of the entire lens module can be reduced by 0.1mm-0.4mm due to the removal of two glue layers. In the entire production process, since the prescription lens is integrally formed on the optical waveguide 5, two alignment and stacking operations are also saved, and thus the production cycle of the entire lens module can be reduced, which is beneficial to reducing the production cost and improving the overall yield of assembly.

[0051] Specifically, in the present application, the refractive index of the filling layer 3 ranges from 1.0 to 1.4, and the refractive index of the first prescription lens 7 is less than or equal to 1.75.

[0052] Specifically, in the present application, the filling layer 3 uses a viscous material with a viscosity less than 20mpas, and the low-refractive layer 4 uses a viscous material with a viscosity greater than 2000mpas, so as to ensure that the filling layer 3 can fill the grooves of the diffraction grating 2, and avoid bubbles in the grooves of the diffraction grating 2.

[0053] Referring to Figure 4 , Figure 4 An embodiment of the present application provides a structure diagram of a semi-finished product A of the lens module. Optionally, in some embodiments of the present application, the second prescription lens 6 has a first covering part attached to the ambient side of the optical waveguide 5 and a second covering part attached to the peripheral side of the optical waveguide 5. In this way, the second prescription lens 6 wraps the optical waveguide 5 when being formed, which is beneficial to improving the structural stability of the lens module. The distance between the side of the second covering part away from the optical waveguide 5 and the peripheral side of the optical waveguide 5 is greater than or equal to 0.1mm, so as to provide an operation space for subsequent polishing or cutting of the lens module. Specifically, in this embodiment of the present application, the distance can reach 0.5mm.

[0054] The thinnest thickness of the current prescription lens is 1.0mm-1.5mm. When the thickness of the prescription lens is further reduced, the prescription lens is prone to problems such as incomplete formation, formation bubbles, edge shrinkage and profile CNC fragmentation under the existing process.

[0055] Optionally, in some embodiments of the present application, the first prescription lens 7 has optical power, and the second prescription lens 6 also has optical power, so that the lens module produced in this way can match myopic or hyperopic people, which is beneficial to realizing customized lenses. As shown in Figure 3 , Figure 3 An embodiment of the present application provides a structure diagram of the lens module in a mold. The center of the mold is concentrically arranged with the coupling-out center of the optical waveguide 5 in the lens module. Since the prescription lens is formed by glue pouring, in this way, the overall thickness of the entire lens module can be reduced while the edge wall thickness of the prescription lens is not too thin, thereby avoiding the problem of poor glue pouring at the edge of the prescription lens. Specifically, as shown in Figure 4 , in this embodiment, the optical power of the second prescription lens 6 is positive. In the lens module produced by the glue pouring forming process, the minimum thickness of the first prescription lens 7 is located at the edge of the substrate 1. The minimum thickness T1 is the minimum distance from the ambient side of the optical waveguide 5 to the side of the first covering part of the second prescription lens 6 away from the optical waveguide 5. By concentrically arranging the center of the mold with the coupling-in center, the minimum thickness can be as small as 0.1mm, so that the material can smoothly flow into the peripheral side of the optical waveguide 5 during the glue pouring process. In addition, different eyeglass powers can be achieved by the combination of optical power, as shown in Figure 5 , Figure 5This is a schematic diagram of the structure of a semi-finished lens module B in one embodiment of this application. In this embodiment, the first prescription lens 7 has negative optical power, and the second prescription lens 6 has positive optical power. Different combinations of optical power can be achieved by adjusting the mold model, thus enabling customization of the lens module's power to meet the needs of different groups of people. It is worth noting that in the embodiment of this application, the minimum thickness T2 of the first prescription lens 7 can be as low as 0.1 mm.

[0056] The optical waveguide has a coupling surface on the human eye side for matching the optical engine. In order to further reduce the thickness of the smart glasses at the coupling surface and reduce the overall thickness of the smart glasses, the lens module provided in this application also has an inward reduction treatment on the lens edge.

[0057] like Figure 6 As shown, Figure 6 This is a schematic diagram of the edge structure of the lens module in Embodiment 1 of this application. The first prescription lens 7 also has a first clearance step 8-a corresponding to the coupling surface. In this way, the emitting end of the optical engine can extend into the first clearance step 8-a, which helps to reduce the thickness of the smart glasses. On the other hand, the distance between the emitting end of the optical engine and the coupling surface is smaller, which can reduce stray light entering the optical waveguide 5, thereby improving image quality. Furthermore, the structure of the first clearance step 8-a reduces the volume and weight of the first prescription lens 7, and also reduces the weight of the entire lens module and even the entire smart glasses, which helps to improve the user's wearing experience. Specifically, the thickness of the first prescription lens 7 at the first clearance step 8-a is less than 0.15mm. In this embodiment, the thickness is 0.1mm, which is processed by CNC technology. This can both reduce the distance between the coupling surface and the emitting surface of the optical engine and form protection for the optical waveguide 5. In actual production, the thickness is adaptively adjusted by the manufacturer according to the production capacity.

[0058] like Figure 7 As shown, Figure 7 The diagram below shows the structure of the lens module edge in Embodiment 2 of this application. In this embodiment, the size of the first prescription lens 7 is smaller than the size of the optical waveguide 5 to form a first recessed step 8-b. The first recessed step 8-b can be used for the support component of the smart glasses to extend into, thereby reducing the size of the entire smart glasses. Furthermore, the coupling surface of the optical waveguide 5 is also located at the first recessed step 8-b, that is, the coupling surface is exposed, so that the output end of the optical engine can also extend into, further reducing the size of the entire smart glasses.

[0059] like Figure 8 As shown, Figure 8The structure schematic diagram of the edge of the lens module in the third embodiment provided by the present application is shown in the figure, in the embodiment, the edge of the second prescription lens 6 is provided with a second accommodating step 9-a, so as to further reduce the thickness of the lens module at the edge, the second accommodating step 9-a is used for accommodating the supporting component clamping the lens module in the smart glasses, so as to further reduce the thickness of the smart glasses, meet the miniaturization trend of the smart glasses, and improve the portability of the smart glasses.

[0060] As shown in the figure, Figure 9 As shown in the figure, Figure 9 The structure schematic diagram of the edge of the lens module in the fourth embodiment provided by the present application is shown in the figure. In the embodiment, the size of the second prescription lens 6 is less than or equal to the size of the optical waveguide 5 to form a second inwardly recessed step 9-b, so as to reduce the size. It can be understood that the second inwardly recessed step 9-b can be directly formed by a mold when the second prescription step is formed, or can be processed by a CNC process. The selection of the specific processing mode is determined by the precision and difficulty of the process.

[0061] For example, the processing process of the lens module involved in the present application is as follows: first, fill the diffraction grating 2 of the substrate 1 with a low-refractive material to form a filling layer 3, and then continue to cover a low-refractive layer 4 on the filling layer 3. At this time, the semi-finished product A of the lens module is formed as shown in the figure, the low-refractive layer 4 covers the entire light propagation path of the substrate 1 to avoid the generation of ghost images. Further, the optical waveguide 5 is suspended at a specific position in the mold, and the coupling-out center of the substrate 1 is aligned with the center of the mold, as shown in the figure. The second prescription lens 6 is formed on the ambient side of the optical waveguide 5 by injection molding, so as to form the semi-finished product B of the lens module. Then, the first prescription lens 7 is injection molded or glued, so as to form the semi-finished product C of the lens module as shown in the figure. Finally, different embodiments shown in the figure are processed by CNC. Figure 2 Figure 3 Figure 5 Figures 6 to 9

[0062] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not conflict, they should be considered within the scope of the present application.

[0063] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the utility model patent should be subject to the appended claims.​​​​

Claims

1. A lens module, characterized by, The application relates to an optical waveguide, a first prescription lens and a second prescription lens. The optical waveguide comprises a substrate, a filling layer and a low-refractive layer, the substrate is provided with a diffraction grating, the filling layer fills the diffraction grating, the low-refractive layer covers the filling layer, the refractive index of the low-refractive layer is different from that of the filling layer, and the viscosity of the filling layer is smaller than that of the low-refractive layer. The first prescription lens is attached to the eye side of the optical waveguide. The second prescription lens is attached to the environment side of the optical waveguide. The refractive indexes of the filling layer, the low-refractive layer, the first prescription lens and the second prescription lens are all smaller than the refractive index of the substrate.

2. The lens module of claim 1, wherein, The refractive index of the filling layer ranges from 1.0 to 1.4, and the refractive index of the first prescription lens is smaller than or equal to 1.

75.

3. The lens module of claim 1, wherein, The first prescription lens has optical power; and / or The second prescription lens has optical power.

4. The lens module of claim 1, wherein, The second prescription lens has a first covering part attached to the environment side of the optical waveguide and a second covering part attached to the circumferential side of the optical waveguide.

5. The lens module of claim 4, wherein, The optical power of the first covering part is positive, and the distance between the side, away from the optical waveguide, of the first covering part and the environment side of the optical waveguide is greater than or equal to 0.1 mm.

6. The lens module of claim 4, wherein, The distance between the side, away from the optical waveguide, of the second covering part and the circumferential side of the optical waveguide is greater than or equal to 0.1 mm.

7. The lens module according to any one of claims 1 to 6, characterized in that, The eye side of the optical waveguide has a coupling-in surface, and the first prescription lens has a first accommodation step corresponding to the coupling-in surface.

8. The lens module according to any one of claims 1 to 6, characterized in that, The size of the first prescription lens is smaller than that of the optical waveguide to form a first inwardly-retracted step.

9. The lens module according to any one of claims 1 to 3, characterized in that, The second prescription lens has a second accommodation step on the edge.

10. The lens module according to any one of claims 1 to 3, characterized in that, The size of the second prescription lens is smaller than that of the optical waveguide to form a second inwardly-retracted step.

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