AR resin lens and preparation method thereof

Abstract

The application discloses an AR resin lens and a preparation method thereof. The AR resin lens comprises a shell and a waveguide substrate wrapped by the shell. The waveguide substrate is integrally provided with a grating structure. The grating structure has a coupling-in area and a coupling-out area. The shell and the waveguide substrate are both optical resin materials. The refractive index of the waveguide substrate is 1.74. The refractive index of the shell is lower than that of the waveguide substrate. The shell has an upper surface and a lower surface with a difference in curvature for correcting vision. The resin optical material has the advantages of small density, light weight, good wearing comfort, high safety, low production cost and the function of correcting vision. The method solves the problems that it is difficult to form a grating structure on other materials and it is difficult to directly form a grating structure by using a glass material for casting molding. The obtained waveguide substrate has good mechanical reliability, small density, light weight and good wearing comfort.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of AR glasses, and more particularly relates to an AR resin lens and a preparation method thereof. BACKGROUND

[0002] In recent years, augmented reality technology has a broad application prospect in the fields of education, security, health management, virtual training, medical research and electronic games. In order to meet such needs, near-eye display devices serving augmented reality technology need to be able to ensure that the light of the real world can directly pass through the device and be captured by the human eye on the basis of achieving good virtual image display effect. This requires the near-eye display device to meet various display performance indicators, including a larger field of view angle, good field of view uniformity, a larger eye movement range and higher display resolution. In addition, considering the wearable use requirements of users, the near-eye display device must also meet the characteristics of light weight, miniaturization and glasses-like form. However, the above requirements often conflict with each other, compete with each other and even contradict each other in actual design, so the design and manufacture of augmented display glasses with excellent performance still have great challenges.

[0003] The existing surface relief grating diffraction optical waveguide is generally made on a glass substrate, and the manufacturing process is: a grating template is prepared in advance, then a stamping glue is coated on the glass substrate, and the stamping glue is formed into a grating structure by using the grating template through a nano-imprinting process. However, since the glass substrate has a large density, the wearing weight is large, and the user experience is not friendly. Moreover, since the glass is brittle, the mechanical reliability of the glass substrate optical waveguide is poor, so it is very fragile when falling, and the glass fragments are sharp glass debris which is dangerous. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned shortcomings, and provide an AR resin lens and a preparation method thereof, which has a vision correction function and can reduce the weight of the optical waveguide lens and improve the wearing comfort of the AR glasses.

[0005] To achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0006] In a first aspect, the present application provides an AR resin lens, comprising a shell and a waveguide substrate wrapped thereby, wherein the waveguide substrate is integrally provided with a grating structure, and the grating structure has a coupling-in area and a coupling-out area; the shell and the waveguide substrate are both made of optical resin material, the refractive index of the waveguide substrate is 1.74, the refractive index of the shell is lower than that of the waveguide substrate, and the shell has an upper and lower surface curvature difference for vision correction function.

[0007] Further, the refractive index of the shell is 1.5-1.67, and the refractive index of the internal waveguide substrate is higher than that of the shell to meet the total reflection condition, so that it is suitable for AR smart glasses.

[0008] Further, the material of the shell can be an optical material commonly used in the art, which can be selected from at least one of CR-39, acrylate, and polyurethane, and the visible light transmittance is not less than 88%.

[0009] Further, the grating structure is protrudingly arranged on the surface of the waveguide substrate, and the grating structure comprises a plurality of sub-structures which are identical in shape and parallel to each other.

[0010] Further, the grating structure can be one of a binary grating, an inclined grating, a blazed grating, or a two-dimensional grating. Generally, the binary grating has a valley structure between the sub-structures, the inclined grating has a certain angle (for example, an angle of 10°-90°) between the sub-structures and the substrate, the blazed grating has a sawtooth-shaped cross section of the sub-structure, and the two-dimensional grating refers to a grating structure having periodic sub-structures in two orthogonal directions (for example, X-axis and Y-axis).

[0011] Further, the period of the grating structure is 150nm-900nm, preferably 300nm-800nm, for example, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, etc.; and the depth of the grating structure is not greater than 400nm, preferably not greater than 280nm, for example, 250nm, 200nm, 100nm, 50nm, 10nm, 1nm, etc.

[0012] Further, the thickness of the resin lens is 1mm-20mm, for example, 1mm, 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc., preferably 1mm-5mm.

[0013] In a second aspect, the present application also provides a preparation method of the waveguide substrate of the first aspect, comprising the following steps:

[0014] forming a grating structure on the first substrate to obtain a first template;

[0015] transferring the grating structure of the first template to the second substrate to obtain a second template having a structure complementary to the grating structure;

[0016] combining the second template and the first structure to form a casting mold, and injecting an optical resin raw material with a refractive index of 1.74 into the mold cavity of the casting mold;

[0017] curing and demolding to obtain the waveguide substrate.

[0018] Further, the method for forming the grating structure on the first substrate comprises coating photoresist on the first substrate, and performing exposure and development to form the grating structure.

[0019] Further, the thickness variation of the first substrate and / or the second substrate is not greater than 40 microns, and the surface roughness of the first substrate and / or the second substrate is not greater than 4 nanometers.

[0020] Further, the first template is made of glass, and the second template is made of metal.

[0021] Further, the second template and the first structure are detachably connected and surround the mold cavity, and the first structure is provided with a pouring hole communicated with the mold cavity.

[0022] In a third aspect, the application further provides a preparation method of the AR resin lens of the first aspect, comprising the following steps:

[0023] The waveguide substrate prepared by the preparation method of the second aspect is fixed in a glass mold for preparing the resin lens,

[0024] After the mold is closed, the shell raw material is poured;

[0025] After curing and forming, the mold is demolded, and the AR resin lens is obtained.

[0026] Further, the glass mold has an upper and lower surface curvature difference for correcting vision, so that the upper and lower surface curvature difference of the prepared AR resin lens meets the various degrees of correction of vision. According to needs, different shapes can also be formed by laser cutting.

[0027] Further, the waveguide substrate is fixed in the glass mold by a rubber ring.

[0028] Further, when the waveguide substrate is fixed in the glass mold, the grating structure is located on the side of the waveguide substrate away from the eye.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The AR resin lens of the application meets the total reflection condition by the refractive index of the shell and the waveguide substrate, is suitable for AR smart glasses, adopts resin optical material, has small density, light weight, good wearing comfort, is not easy to break when falling, high safety, low production cost, and has the function of correcting vision;

[0031] The waveguide substrate preparation method of the present invention solves the problem of not being able to form grating structures on other materials by transferring the first substrate and the second substrate, and also solves the problem of not being able to cast and mold the grating structure directly using glass. The waveguide substrate obtained by casting resin curing molding method has good mechanical reliability, low density, light weight and good wearing comfort. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of an AR resin lens provided in Example 1;

[0033] Figure 2 This is a schematic diagram illustrating the usage state of the AR resin lens described in Example 1;

[0034] Figure 3 This is a top view of the waveguide substrate described in Example 1;

[0035] Figure 4 This is a three-dimensional structural diagram of the waveguide substrate described in Example 1;

[0036] Figure 5 This is a schematic diagram of the casting mold for the waveguide substrate described in Example 2;

[0037] Figure 6 This is a cross-sectional view of the glass mold being closed as described in Example 3.

[0038] In the figure: 1-shell, 2-waveguide substrate, 21-grating structure, 22-coupled area, 23-coupled area, 3-first component, 4-second template, 5-pouring hole, 6-upper mold, 7-lower mold, 8-rubber ring. Detailed Implementation

[0039] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings and specific examples. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0040] Example 1

[0041] like Figures 1 to 3 An AR resin lens is shown, comprising a housing 1 and a waveguide substrate 2 encased therein. The waveguide substrate 2 is integrally provided with a grating structure 21, which has a coupling-in region 22 and a coupling-out region 23. Both the housing 1 and the waveguide substrate 2 are made of optical resin. The refractive index of the waveguide substrate 2 is 1.74, and the refractive index of the housing 1 is lower than that of the waveguide substrate 2. The housing 1 has a difference in curvature between its upper and lower surfaces for vision correction.

[0042] The refractive index of the shell 1 is 1.5-1.67, and the refractive index of the internal waveguide substrate 2 is higher than that of the shell to meet the condition of total reflection, so that it is suitable for AR smart glasses. The material of the shell 1 can be an optical material commonly used in the art, which can be selected from at least one of CR-39, acrylate, and polyurethane, and the visible light transmittance is not less than 88%.

[0043] As shown in Figure 4 The grating structure 21 of the present embodiment is protrudingly arranged on the surface of the waveguide substrate 2, and the grating structure 21 includes a plurality of sub-structures which are the same in shape and parallel to each other, and is generally arranged on the side of the waveguide substrate 2 away from the eye, as shown in Figure 2 .

[0044] The specific structure of the grating structure 21 is not particularly limited, and in some embodiments of the present application, the grating structure 21 can be one of a binary grating, an inclined grating, a blazed grating, or a two-dimensional grating. Generally, there is a valley structure between the sub-structures of the binary grating, there is a certain angle (for example, an angle of 10°-90°) between the sub-structures of the inclined grating and the substrate, the cross section of the sub-structure of the blazed grating is sawtooth-shaped, and the two-dimensional grating refers to a grating structure having periodic sub-structures in two orthogonal directions (for example, X-axis and Y-axis).

[0045] In some embodiments of the present application, the period of the grating structure 21 can be 300-800 nm, for example, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, etc.; the depth of the grating structure 21 is not more than 280 nm, for example, 250 nm, 200 nm, 100 nm, 50 nm, 10 nm, 1 nm, etc.

[0046] In some embodiments of the present application, the thickness of the resin lens is 1-20 mm, for example, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., preferably 1-5 mm.

[0047] Example 2

[0048] The present embodiment provides a preparation method of the waveguide substrate of Example 1, comprising the following steps:

[0049] forming a grating structure on the first substrate to obtain a first template;

[0050] transferring the grating structure of the first template to the second substrate to obtain a second template 4 having a structure complementary to the grating structure;

[0051] The second template 4 and the first structural member 3 are combined to form a casting mold, and an optical resin raw material with a refractive index of 1.74 is injected into a mold cavity of the casting mold;

[0052] Curing and demolding to obtain the waveguide substrate.

[0053] The specific method for forming the grating structure on the first substrate in this embodiment is to coat photoresist on the first substrate and perform exposure and development to form the grating structure. The first substrate is pre-cleaned. It should be noted that the specific operation conditions, parameters, etc. for forming the grating structure are not particularly limited and can be determined according to the actual required grating structure.

[0054] The transfer of the grating structure of the first template to the second substrate in this embodiment is realized by an electroforming process. The grating structure is transferred to the second substrate to obtain a complementary structure to the original grating structure on the first substrate on the second substrate. Then, the second template 4 is used for casting to obtain a waveguide substrate with the original grating structure.

[0055] In order to further improve the flatness of the surface of the prepared waveguide substrate and thus improve the optical performance of the entire AR lens, the thickness variation of the first substrate and / or the second substrate is not greater than 40 pm, and the surface roughness of the first substrate and / or the second substrate is not greater than 4 nm. By controlling the first substrate and / or the second substrate to meet the above conditions, the flatness of the surface of the prepared waveguide substrate is better.

[0056] The first substrate in this embodiment is of glass material, and the second substrate is of metal material. Because the glass substrate surface is easy to be photoetched to form a grating structure, but considering that the first substrate is composed of glass and photoresist, the photoresist is not resistant to high temperature and is easy to be damaged, it is difficult to meet the casting and curing requirements, and therefore the complementary structure of the grating structure is transferred to the metal substrate to facilitate subsequent casting to obtain an optical waveguide lens product with the original grating structure.

[0057] The second template 4 and the first structural member 3 in this embodiment are detachably connected and surround the mold cavity; the first structural member 3 is provided with a casting hole 5 communicating with the mold cavity.

[0058] Embodiment 3

[0059] This embodiment provides a preparation method of the AR resin lens of embodiment 1, comprising the following steps:

[0060] The waveguide substrate 2 prepared in embodiment 2 is fixed in a glass mold for preparing a resin lens by a rubber ring 8, so that the grating structure 21 is located on the side of the waveguide substrate 2 away from the eye, as shown in Figure 6 The upper mold 6 and the lower mold 7 of the glass mold have a curvature difference for correcting vision function,

[0061] After the mold is closed, the pouring shell raw material is poured;

[0062] After curing and molding, the mold is removed;

[0063] After opening the mold, cleaning is performed, and the desired shape is obtained by laser cutting.

[0064] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; 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 communication between the two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0065] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; 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 communication between the two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0066] The above has described the embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and technical principles of the described embodiments, and these modifications and changes should be considered as the protection scope of the present application.

Claims

1. An AR resin lens, characterized by, The application relates to an AR resin lens, which comprises a shell and a waveguide substrate wrapped by the shell, wherein a grating structure is integrally arranged on the waveguide substrate, the grating structure is provided with a coupling-in area and a coupling-out area, the grating structure is located on the side of the waveguide substrate far from the eyes, the shell and the waveguide substrate are made of optical resin, the refractive index of the waveguide substrate is 1.74, the refractive index of the shell is lower than that of the waveguide substrate, and the upper and lower surfaces of the shell have a curvature difference for correcting vision. The refractive index of the shell is 1.5-1.67; the material of the shell is selected from at least one of CR-39, acrylate and polyurethane, and the visible light transmittance is not lower than 88%.

2. The AR resin lens of claim 1, wherein, The grating structure is protrudingly arranged on the surface of the waveguide substrate, and the grating structure comprises a plurality of substructures which are identical in shape and parallel to each other.

3. The AR resin lens of claim 1, wherein, The grating structure is one of a binary grating, an inclined grating, a blazed grating or a two-dimensional grating.

4. The AR resin lens of claim 1, wherein, The period of the grating structure is 150nm-900nm, and the depth of the grating structure is not greater than 400nm.

5. The AR resin lens of claim 1, wherein, The thickness of the AR resin lens is 1mm-20mm.

6. A method of producing the AR resin lens according to any one of claims 1 to 5, characterized by, The application further discloses a preparation method of the AR resin lens, which comprises the following steps: The waveguide substrate is fixed in a glass mold for preparing the AR resin lens, so that the grating structure is located on the side of the waveguide substrate far from the eyes; After the mold is closed, the shell raw material is poured; After curing and forming, the mold is demolded, and the AR resin lens is obtained; The preparation method of the waveguide substrate comprises the following steps: A grating structure is formed on a first substrate to obtain a first template; The grating structure of the first template is transferred to a second substrate to obtain a second template with a structure complementary to the grating structure; The second template and a first structural member are combined to form a pouring mold, and an optical resin raw material with a refractive index of 1.74 is injected into a mold cavity of the pouring mold; Curing and demolding are performed to obtain the waveguide substrate.

7. The production method according to claim 6, wherein The method for forming the grating structure on the first substrate comprises the following steps: coating photoresist on the first substrate, and performing exposure and development to form the grating structure.

8. The preparation method according to claim 6, characterized in that, The thickness variation of the first substrate and / or the second substrate is not greater than 40mu m, and the surface roughness of the first substrate and / or the second substrate is not greater than 4nm.

9. The preparation method according to claim 6, characterized in that, The first template is made of glass, and the second template is made of metal.

10. The method of claim 6, wherein, The second template and the first structural member are detachably connected and surround the mold cavity; and the first structural member is provided with a pouring hole which is communicated with the mold cavity.

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