Manufacturing method of diffraction optical waveguide, diffraction optical waveguide and near-to-eye display device

Abstract

The invention discloses a manufacturing method of a diffraction optical waveguide, the diffraction optical waveguide and a near-to-eye display device. The manufacturing method of the diffraction optical waveguide comprises the following steps: forming a liquid bonding layer on a first surface of a covering layer; the liquid bonding layer is pre-cured, so that the liquid bonding layer is converted into a pre-cured layer; patterning the pre-cured layer, and forming a groove in the surface, deviating from the covering layer, of the pre-cured layer; a first optical waveguide layer with an optical grating is attached to the covering layer through a pre-curing layer, the second surface, provided with the optical grating, of the first optical waveguide layer is arranged opposite to the first surface, and the optical grating corresponds to the groove in position; and curing the pre-cured layer so that the pre-cured layer is converted into a solid bonding layer and the first optical waveguide layer is bonded with the covering layer. According to the manufacturing method of the diffraction optical waveguide, the relative deformation between the middle-layer structures of the diffraction optical waveguide can be reduced, so that the stability of the display effect is improved.

Description

Technical Field

[0001] The present application relates to the field of near-eye display, and in particular to a method for manufacturing a diffractive optical waveguide, a diffractive optical waveguide and a near-eye display device. Background Art

[0002] An augmented reality (AR) near-eye display device generally includes an optical machine and a diffractive optical waveguide, wherein the diffractive optical waveguide includes several optical waveguide layers and at least one protective layer, and a grating is provided on one side of the optical waveguide layer. Taking the diffractive optical waveguide including an optical waveguide layer and a protective layer as an example, in the prior art, after the optical waveguide layer and the protective layer are assembled, there is a gap layer between the optical waveguide layer and the protective layer when no external force is applied. When the air pressure of the gap layer is lower than the external air pressure or the diffractive optical waveguide is subjected to an external force, the optical waveguide layer and the protective layer may be relatively deformed, resulting in the stability of the display effect being affected. Summary of the invention

[0003] The present application provides a method for manufacturing a diffractive optical waveguide, a diffractive optical waveguide and a near-eye display device, which can reduce the relative deformation between layer structures in the diffractive optical waveguide to improve the stability of the display effect.

[0004] In a first aspect, an embodiment of the present application provides a method for manufacturing a diffractive optical waveguide, comprising: forming a liquid adhesive layer on a first surface of a covering layer; pre-curing the liquid adhesive layer so that the liquid adhesive layer is transformed into a pre-cured layer; patterning the pre-cured layer to form a groove on a surface of the pre-cured layer away from the covering layer; bonding a first optical waveguide layer having a grating to the covering layer through the pre-cured layer, wherein a second surface of the first optical waveguide layer having the grating is arranged opposite to the first surface, and the grating corresponds to the position of the groove; curing the pre-cured layer so that the pre-cured layer is transformed into a solid adhesive layer and the first optical waveguide layer is bonded to the covering layer.

[0005] According to any of the aforementioned embodiments of the first aspect of the present application, forming a liquid adhesive layer on the first surface of the covering layer includes: forming a liquid adhesive layer of uniform thickness on the first surface of the covering layer by electrostatic adsorption coating, electromagnetic adsorption coating or centrifugal force coating.

[0006] According to any of the aforementioned embodiments of the first aspect of the present application, pre-curing the liquid adhesive layer to transform the liquid adhesive layer into a pre-cured layer includes: performing a viscosity-enhancing treatment on the liquid adhesive layer to obtain a pre-cured layer that can maintain its shape unchanged under external forces within a preset range.

[0007] According to any of the aforementioned embodiments of the first aspect of the present application, patterning the pre-cured layer to form a groove on the surface of the pre-cured layer away from the covering layer includes: setting a patterned mask on the side of the pre-cured layer away from the covering layer, the patterned mask having a mask opening; etching the pre-cured layer using the patterned mask to form a groove in the area of ​​the pre-cured layer corresponding to the mask opening; and peeling off the patterned mask.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the etching depth of the pre-cured layer is less than 200 nm, so that the depth of the groove is less than 200 nm.

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, in the step of bonding the first optical waveguide layer having the grating to the cover layer through the pre-cured layer, the bonding pressure and bonding time are controlled so that the thickness of the pre-cured layer varies within 200 nm.

[0010] According to any of the aforementioned implementations of the first aspect of the present application, the covering layer is a protective layer; or the covering layer is a second optical waveguide layer.

[0011] In a second aspect, an embodiment of the present application provides a diffractive optical waveguide, which is obtained by a method for manufacturing a diffractive optical waveguide according to any of the aforementioned embodiments of the first aspect of the present application.

[0012] In a third aspect, an embodiment of the present application provides a diffractive optical waveguide, comprising: a covering layer having a first surface; a first optical waveguide layer having a second surface, the first optical waveguide layer having a grating on the second surface; an adhesive layer, the first optical waveguide layer is bonded and adhered to the covering layer through the adhesive layer, the second surface is arranged opposite to the first surface, the adhesive layer is arranged between the first optical waveguide layer and the covering layer or on the peripheral surface of the area where the first optical waveguide layer and the covering layer are connected, the adhesive layer is used to bond the first optical waveguide layer and the covering layer in a vacuum environment and eliminate air in the bonding surface of the first optical waveguide layer and the covering layer.

[0013] In a fourth aspect, an embodiment of the present application provides a diffractive optical waveguide, comprising: a covering layer having a first surface; a first optical waveguide layer having a second surface, the first optical waveguide layer having a grating on the second surface; an adhesive layer, the first optical waveguide layer being attached and bonded to the covering layer through the adhesive layer, the second surface being arranged opposite to the first surface, the adhesive layer being arranged between the first optical waveguide layer and the covering layer, the surface of the adhesive layer facing away from the covering layer having a groove, the grating corresponding to the position of the groove, so that there is a gap between the grating and the surface of the adhesive layer.

[0014] According to the aforementioned implementation of the fourth aspect of the present application, the depth of the groove is 0 to 200 nm.

[0015] According to any of the aforementioned implementations of the fourth aspect of the present application, the covering layer is a second optical waveguide layer.

[0016] According to any of the aforementioned implementations of the fourth aspect of the present application, a first alignment mark is provided on the cover layer, and a second alignment mark corresponding to the first alignment mark is provided on the first optical waveguide layer.

[0017] In a fifth aspect, an embodiment of the present application provides a diffractive optical waveguide, comprising: a covering layer having a first surface; a first optical waveguide layer having a second surface, the first optical waveguide layer having a grating on the second surface; an adhesive layer, the first optical waveguide layer being bonded and adhered to the covering layer through the adhesive layer, the second surface being arranged opposite to the first surface, the adhesive layer being arranged at the peripheral edge of the region where the first optical waveguide layer and the covering layer are in contact, the adhesive layer being used to bond the first optical waveguide layer and the covering layer in a vacuum environment and to eliminate air in the bonding surface between the first optical waveguide layer and the covering layer.

[0018] According to the aforementioned embodiment of the fifth aspect of the present application, the adhesive layer is provided at the peripheral edge and the peripheral side area of ​​the area where the first optical waveguide layer and the cover layer are in contact.

[0019] In a sixth aspect, an embodiment of the present application provides a near-eye display device, comprising: an optical machine for emitting signal light; and a diffraction optical waveguide according to any of the foregoing embodiments of the present application, for transmitting the signal light.

[0020] According to the method for manufacturing a diffractive optical waveguide of an embodiment of the present application, a diffractive optical waveguide with a specific structure can be provided, wherein a solid adhesive layer fully bonds the first optical waveguide layer to the covering layer, and when the diffractive optical waveguide is subjected to an external force, the relative deformation between the first optical waveguide layer and the covering layer is reduced, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide transmits signal light. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 A flow chart of an embodiment of a method for manufacturing a diffractive optical waveguide according to the present invention;

[0023] Figure 2 It is a schematic structural diagram of forming a liquid adhesive layer on the first surface of the cover layer in one embodiment of the method for manufacturing a diffractive optical waveguide of the present invention;

[0024] Figure 3 It is a schematic structural diagram of pre-curing the liquid adhesive layer in an embodiment of the method for manufacturing a diffractive optical waveguide of the present invention, so that the liquid adhesive layer is transformed into a pre-cured layer;

[0025] Figure 4 It is a schematic structural diagram of patterning a pre-cured layer in an embodiment of a method for manufacturing a diffractive optical waveguide of the present invention, and forming grooves on a surface of the pre-cured layer away from the cover layer;

[0026] Figure 5 It is a structural schematic diagram of laminating a first optical waveguide layer having a grating to a cover layer through a pre-cured layer in an embodiment of a method for manufacturing a diffractive optical waveguide of the present invention;

[0027] Figure 6 It is a schematic structural diagram of curing the pre-cured layer in an embodiment of the method for manufacturing a diffractive optical waveguide of the present invention, so that the pre-cured layer is transformed into a solid adhesive layer and the first optical waveguide layer is bonded to the cover layer;

[0028] Figure 7 It is a schematic structural diagram of an embodiment of a diffractive optical waveguide of the present invention;

[0029] Figure 8 is a schematic structural diagram of another embodiment of a diffractive optical waveguide of the present invention;

[0030] Fig. 9 It is a structural schematic diagram of another embodiment of the diffractive optical waveguide of the present invention;

[0031] Fig.10 FIG. 4 is a schematic cross-sectional structural diagram of an embodiment of a near-eye display device of the present invention.

[0032] The purpose, features and advantages of this application will be further described in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] It should be noted that all directional indications in the embodiments of the present application, such as up, down, left, right, front, back, etc., are only used to explain the relative position relationship, movement, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly. When describing the structure of a component, when a layer or an area is referred to as being "above" or "above" another layer or another area, it may refer to being directly above another layer or another area, or containing other layers or areas between it and another layer or another area. Furthermore, if the component is turned over, the layer or the area will be "below" or "below" another layer or another area.

[0035] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by this application.

[0036] Diffractive optical waveguides can be used in augmented reality (AR) display devices, such as AR glasses. Diffractive optical waveguides can be used to transmit signal light emitted by an optical machine.

[0037] In the related art, taking the diffraction optical waveguide including a layer of optical waveguide layer and a layer of protective layer as an example, after the optical waveguide layer and the protective layer are assembled, there is a gap layer between the optical waveguide layer and the protective layer when no external force is applied. When the air pressure of the gap layer is lower than the external air pressure or the diffraction optical waveguide is subjected to external force, the optical waveguide layer and the protective layer may produce relative deformation. After deformation, some areas of the diffraction optical waveguide are prone to interference, resulting in Newton rings, which affects the observation effect of the user. The stability of the display effect of the diffraction optical waveguide needs to be improved. In order to avoid the generation of Newton rings, in the related art, a glue layer is also filled between the optical waveguide layer and the protective layer. In the process of filling the glue layer, the glue layer is also filled into the grating microstructure, so that the optical performance of the waveguide will be reduced and the display effect is poor.

[0038] The embodiments of the present application provide a method for manufacturing a diffractive optical waveguide and a diffractive optical waveguide manufactured according to the method for manufacturing a diffractive optical waveguide.

[0039] Figure 1 FIG. 1 is a flow chart of an embodiment of a method for manufacturing a diffractive optical waveguide according to the present invention. The method for manufacturing a diffractive optical waveguide includes steps S110 to S160.

[0040] In step S110 , a cover layer is provided.

[0041] In some embodiments, the covering layer is a protective layer, and the material of the protective layer can be resin, glass, or silicon wafer.

[0042] In some embodiments, the cover layer is a second optical waveguide layer, that is, the diffractive optical waveguide may include two or more optical waveguide layers, and the cover layer is another optical waveguide layer different from the first optical waveguide layer.

[0043] In this embodiment, the cover layer is used as the protective layer, and the diffraction optical waveguide includes a waveguide layer and a protective layer. In other embodiments, the diffraction optical waveguide may include other numbers of waveguide layers, or may include multiple protective layers.

[0044] In step S120 , a liquid adhesive layer is formed on the first surface of the cover layer. Figure 2 The structure schematic diagram of forming a liquid adhesive layer on the first surface of the cover layer in one embodiment of the method for manufacturing a diffractive optical waveguide of the present invention. In this embodiment, liquid adhesive is applied on the first surface of the cover layer to form the liquid adhesive layer.

[0045] In some embodiments, the step S120 of forming the liquid adhesive layer 120a on the first surface S1 of the cover layer 110 includes: forming a liquid adhesive layer 120a with uniform thickness on the first surface S1 of the cover layer 110 by electrostatic adsorption coating, electromagnetic adsorption coating or centrifugal force coating.

[0046] In step S130 , the liquid adhesive layer 120 a is pre-cured, so that the liquid adhesive layer 120 a is transformed into a pre-cured layer 120 b . Figure 3 It is a structural schematic diagram of pre-curing the liquid adhesive layer 120a in one embodiment of the method for manufacturing a diffractive optical waveguide of the present invention, so that the liquid adhesive layer 120a is transformed into a pre-cured layer 120b.

[0047] In some embodiments, the above-mentioned step S130 of pre-curing the liquid adhesive layer 120a so that the liquid adhesive layer 120a is transformed into a pre-cured layer 120b includes: performing a viscosity-enhancing treatment on the liquid adhesive layer 120a to obtain a pre-cured layer 120b that can maintain its shape unchanged under a preset range of external forces. The specific method of performing a viscosity-enhancing treatment on the liquid adhesive layer 120a can be determined according to the physical properties of the liquid adhesive layer. For different types of glue (liquid adhesive layer 120a) such as temperature-sensitive glue, humidity-curing glue, and photosensitive glue, the corresponding type of glue can be pre-cured by adjusting the temperature, humidity, light, etc. For example, for a UV-sensitive liquid adhesive layer 120a, UV light irradiation under a preset time length is performed to pre-cure the liquid adhesive layer 120a, so that the pre-cured glue can also be formed when subjected to external forces.

[0048] In step S140 , the pre-cured layer 120 b is patterned to form grooves on a surface of the pre-cured layer 120 b facing away from the cover layer 110 . Figure 4 1 is a schematic structural diagram of patterning the pre-cured layer 120 b and forming grooves on the surface of the pre-cured layer 120 b away from the cover layer 110 in an embodiment of the method for manufacturing a diffractive optical waveguide of the present invention.

[0049] In some embodiments, the above-mentioned patterned pre-cured layer 120b, step S140 of forming a groove 121 on the surface of the pre-cured layer 120b away from the covering layer 110 includes: setting a patterned mask on the side of the pre-cured layer 120b away from the covering layer 110, and the patterned mask has a mask opening; using the patterned mask to etch the pre-cured layer 120b to form a groove 121 in the area of ​​the pre-cured layer 120b corresponding to the mask opening; peeling off the patterned mask.

[0050] In one example, the patterned mask is a patterned photoresist layer. Therefore, the process of forming the patterned mask is, for example: spin coating a positive photoresist layer or a negative photoresist layer on the side of the pre-cured layer 120b facing away from the covering layer 110, and then exposing and developing the positive photoresist layer or the negative photoresist layer under the mask, so that the glue layer in a specific area of ​​the positive photoresist layer or the negative photoresist layer is removed to form a mask opening, that is, a patterned mask with a mask opening is obtained.

[0051] In step S150 , the first optical waveguide layer 130 having the grating 131 is bonded to the cover layer 110 via the pre-cured layer 120 b , wherein the second surface S2 of the first optical waveguide layer 130 having the grating 131 faces the first surface S1 of the cover layer 110 , and the grating 131 corresponds to the groove 121 . Figure 5 It is a structural schematic diagram of laminating the first optical waveguide layer 130 having the grating 131 to the cover layer 110 via the pre-cured layer 120b in one embodiment of the manufacturing method of the diffraction optical waveguide of the present invention.

[0052] In some embodiments, the grating 131 includes an in-coupling grating 131a and an out-coupling grating 131b that are spaced apart from each other. The in-coupling grating 131a is used to couple the signal light emitted by the optical machine (or light engine) into the first optical waveguide layer 130 and cause total reflection. The signal light is transmitted to the out-coupling grating 131b after total reflection in the first optical waveguide layer 130. The out-coupling grating 131b diffracts the signal light in the first optical waveguide layer 130 into free space. The signal light diffracted into the free space enters the human eye and forms a virtual image to be displayed on the retina.

[0053] In some embodiments, the pre-cured layer 120 b is etched to a depth of less than 200 nm, so that the depth of the groove 121 is less than 200 nm.

[0054] In the above embodiment, a groove 121 is formed on the surface of the pre-cured layer 120b away from the cover layer 110. The groove 121 corresponds to the position of the grating 131 on the first waveguide layer 130 after the first waveguide layer 130 is attached to the cover layer 110. The groove 121 allows a gap between the grating 131 and the pre-cured layer 120b or between the grating 131 and the surface of the solid adhesive layer. After the diffraction waveguide is manufactured, the gap forms a thin gap space between the grating 131 and the surface of the solid adhesive layer. According to the Newton ring formation condition, when the gap space thickness d<λ / 2≈200nm (where λ is the minimum wavelength of visible light, λ≈400nm), no light and dark Newton rings can be seen in appearance. In the method for manufacturing the diffraction optical waveguide of the present embodiment, the etching depth of the pre-cured layer 120b is less than 200nm, so that the depth of the groove 121 is less than 200nm, which can ensure that the glue layer (pre-cured layer 120b or solid adhesive layer) does not penetrate into the grating 131 and avoid the generation of Newton rings. Therefore, when using any glue layer, it is possible to ensure the display light effect and avoid the generation of Newton rings.

[0055] In some embodiments, the step of laminating the first optical waveguide layer 130 having the grating 131 to the cover layer 110 through the pre-cured layer 120 b may include laminating the first optical waveguide layer 130 having the grating 131 to the cover layer 110 through the pre-cured layer 120 b in a vacuum environment.

[0056] In the above embodiment, the first optical waveguide layer 130 and the cover layer 110 are bonded under a vacuum environment (vacuum degree <30pa), and the first optical waveguide layer 130 and the cover layer 110 are bonded by mechanical pressure. After the bonding is completed, the first optical waveguide layer 130 and the cover layer 110 are tightly bonded under the action of atmospheric pressure to obtain a diffractive optical waveguide component. This bonding method can reduce or even eliminate the air in the gap of the grating 131, improve the bonding force and optical performance between the first optical waveguide layer 130 and the cover layer 110, and make the first optical waveguide layer 130 and the cover layer 110 have lower warpage after bonding, thereby improving the display yield of the diffractive optical waveguide.

[0057] In some embodiments, the cover layer 110 is provided with a first alignment mark, and the first optical waveguide layer 130 is provided with a second alignment mark. The above-mentioned step of bonding the first optical waveguide layer 130 having the grating 131 to the cover layer 110 through the pre-cured layer 120b may include: identifying the position of the first alignment mark and the position of the second alignment mark through the image acquisition module, and obtaining the position deviation between the second alignment mark and the first alignment mark; and compensating the relative position of the first optical waveguide layer 130 and the cover layer 110 based on the position deviation until the second alignment mark coincides with the first alignment mark. By using the image acquisition module to identify the first alignment mark and the second alignment mark, the position of the first optical waveguide layer 130 and the cover layer 110 can be accurately calibrated to ensure the alignment accuracy of the bonding of the first optical waveguide layer 130 and the cover layer 110.

[0058] In step S160 , the pre-cured layer 120 b is cured, so that the pre-cured layer 120 b is transformed into a solid adhesive layer 120 c and bonds the first optical waveguide layer 130 to the cover layer 110 . Figure 6 It is a schematic structural diagram of curing the pre-cured layer 120 b in an embodiment of the method for manufacturing a diffractive optical waveguide of the present invention, so that the pre-cured layer 120 b is transformed into a solid adhesive layer 120 c and the first optical waveguide layer 130 is bonded to the cover layer 110 .

[0059] In an exemplary solution, a UV-sensitive liquid adhesive layer 120a is used. Accordingly, the step of curing the pre-cured layer 120b is, for example, specifically: degassing the bonded diffractive optical waveguide (i.e., the assembly obtained by bonding the first optical waveguide layer 130 with the cover layer 110 through the pre-cured layer 120b) under high temperature and high pressure conditions, and then exposing it under UV light conditions, so that the pre-cured layer 120b is converted into a solid adhesive layer 120c, thereby achieving the curing of the liquid adhesive between the first optical waveguide layer 130 and the cover layer 110. The above treatment can increase the bonding strength between the first optical waveguide layer 130 and the cover layer 110, and increase the stability of the diffractive optical waveguide and the lens assembly.

[0060] In some embodiments, in the step S160 of laminating the first optical waveguide layer 130 having the grating 131 to the cover layer 110 through the pre-cured layer 120 b , the laminating pressure and laminating time are controlled so that the thickness of the pre-cured layer 120 b varies within 200 nm.

[0061] According to the manufacturing method of the diffractive optical waveguide of the embodiment of the present application and the diffractive optical waveguide obtained by the manufacturing method, the solid adhesive layer 120c fully bonds the first optical waveguide layer 130 and the cover layer 110, and most of the area between the first optical waveguide layer 130 and the cover layer 110 is filled by the solid adhesive layer 120c, eliminating most of the gap between the first optical waveguide layer 130 and the cover layer 110. Therefore, even if the diffractive optical waveguide is subjected to external force, the relative deformation between the first optical waveguide layer 130 and the cover layer 110 is smaller due to the filling effect of the solid adhesive layer 120c, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide transmits the signal light. In the manufacturing process of the diffractive optical waveguide, by pre-curing the liquid adhesive layer 120a, the pre-cured layer 120b obtained by the transformation can be patterned. By patterning the pre-cured layer 120b, a groove 121 can be formed on the surface of the pre-cured layer 120b away from the cover layer 110. The groove 121 corresponds to the position of the grating 131 on the first optical waveguide layer 130 after the first optical waveguide layer 130 is bonded to the cover layer 110. The groove 121 allows a gap to exist between the grating 131 and the pre-cured layer 120b or between the grating 131 and the surface of the solid adhesive layer 120c. In this way, during the manufacturing process of the diffraction optical waveguide, the glue layer (pre-cured layer 120b or solid adhesive layer 120c) will not penetrate into the grating 131 on the first optical waveguide layer 130, thereby avoiding the influence of the glue layer penetrating into the grating 131 on the grating 131, and the duty cycle of the grating 131 can be kept consistent with the designed value. Since the pre-cured layer 120 b will not penetrate into the grating 131 , the refractive index of the liquid adhesive layer 120 a is no longer restricted when selecting the material, thereby reducing the material requirements for the liquid adhesive layer 120 a .

[0062] The present application also provides a diffraction optical waveguide, such as Figure 7 or Figure 8 or Fig. 9 The diffraction optical waveguide 100 includes a cover layer 110, a first optical waveguide layer 130, and an adhesive layer 120x. The cover layer 110 has a first surface S1. The first optical waveguide layer 130 has a second surface S2, and the first optical waveguide layer 130 has a grating 131 on the second surface S2. The first optical waveguide layer 130 is attached and bonded to the cover layer 110 through the adhesive layer 120x, and the second surface S2 is arranged opposite to the first surface S1. The adhesive layer 120x is arranged between the first optical waveguide layer 130 and the cover layer 110 or on the outer peripheral surface of the area where the first optical waveguide layer 130 and the cover layer 110 are connected. The adhesive layer 120x is used to bond the first optical waveguide layer 130 and the cover layer 110 in a vacuum environment and eliminate the air in the bonding surface of the first optical waveguide layer 130 and the cover layer 110.

[0063] like Figure 7 In some embodiments, the adhesive layer 120x is disposed between the first optical waveguide layer 130 and the cover layer 110. The surface of the adhesive layer 120x facing away from the cover layer 110 has a groove 121, and the grating 131 corresponds to the position of the groove 121, so that there is a gap between the grating 131 and the surface of the adhesive layer 120x. In some embodiments, the depth of the groove 121 is less than 200nm. At the same time, the diffraction optical waveguide component is designed to achieve close bonding by laminating the first optical waveguide layer 130 and the cover layer 110 under a vacuum environment (vacuum degree <30pa) through mechanical pressure, which can eliminate the air in the gap of the grating 131, improve the bonding force and optical performance between the first optical waveguide layer 130 and the cover layer 110, reduce the warping after the two are laminated, and improve the display yield of the diffraction optical waveguide.

[0064] The embodiment of the present application also provides a diffractive optical waveguide, Figure 7 Schematic diagram of the structure of an embodiment of the diffraction optical waveguide of the present invention. The diffraction optical waveguide 100 includes a covering layer 110, a first optical waveguide layer 130, and an adhesive layer 120x. The covering layer 110 has a first surface S1. The first optical waveguide layer 130 has a second surface S2. The first optical waveguide layer 130 has a grating 131 on the second surface S2. The first optical waveguide layer 130 is attached and bonded to the covering layer 110 through the adhesive layer 120x. The second surface S2 is arranged opposite to the first surface S1. The surface of the adhesive layer 120x facing away from the covering layer 110 has a groove 121, and the grating 131 corresponds to the position of the groove 121, so that there is a gap between the grating 131 and the surface of the adhesive layer 120x. In this embodiment, the adhesive layer 120x is a solid adhesive layer, which is obtained by curing a liquid adhesive layer.

[0065] According to the diffractive optical waveguide 100 of the embodiment of the present application, the adhesive layer 120x fully bonds the first optical waveguide layer 130 and the cover layer 110, and most of the area between the first optical waveguide layer 130 and the cover layer 110 is filled by the adhesive layer 120x, thereby eliminating most of the gap between the first optical waveguide layer 130 and the cover layer 110. Therefore, even if the diffractive optical waveguide 100 is subjected to an external force, the relative deformation between the first optical waveguide layer 130 and the cover layer 110 is smaller due to the filling effect of the adhesive layer 120x, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide 100 transmits the signal light. There is a gap between the grating 131 and the surface of the adhesive layer 120x, so that during the manufacturing process of the diffraction optical waveguide 100, the adhesive layer used to form the adhesive layer 120x will not penetrate into the grating 131 on the first optical waveguide layer 130, thereby avoiding the influence of the adhesive layer penetrating into the grating 131 on the grating 131, and the duty cycle of the grating 131 can be kept consistent with the design value. Since the adhesive layer will not penetrate into the grating 131, the refractive index of the adhesive layer is no longer restricted when selecting the material, thereby reducing the material requirements for the adhesive layer.

[0066] In some embodiments, the depth of the groove 121 is 0 to 200 nm, that is, the depth of the groove 121 is less than 200 nm. In the above embodiments, the groove 121 allows a gap between the grating 131 and the pre-cured layer 120b or between the grating 131 and the surface of the adhesive layer 120x, and the gap is equivalent to a thin gap space retained between the grating 131 and the surface of the adhesive layer 120x. According to the Newton ring formation conditions, when the gap space thickness d<λ / 2≈200nm (where λ is the minimum wavelength of visible light, λ≈400nm), the light and dark Newton rings cannot be seen in appearance. Since the depth of the groove 121 is less than 200nm, it can ensure that the glue layer will not penetrate into the grating 131, and at the same time avoid the generation of Newton rings.

[0067] like Figure 8 In some other embodiments, the adhesive layer 120x is disposed at the peripheral edge of the region where the first optical waveguide layer 130 and the cover layer 110 are connected. The adhesive layer 120x is used to bond the first optical waveguide layer 130 and the cover layer 110 in a vacuum environment and eliminate air in the bonding surface of the first optical waveguide layer 130 and the cover layer 110.

[0068] Specifically, the diffraction optical waveguide 100 includes a cover layer 110, a first optical waveguide layer 130, and an adhesive layer 120x. The cover layer 110 has a first surface S1. The first optical waveguide layer 130 has a second surface S2, and the first optical waveguide layer 130 has a grating 131 on the second surface S2. The first optical waveguide layer 130 is attached and bonded to the cover layer 110 through the adhesive layer 120x, and the second surface S2 is arranged opposite to the first surface S1. The adhesive layer 120x is arranged at the outer peripheral edge of the area where the first optical waveguide layer 130 and the cover layer 110 are connected. The adhesive layer 120x is used to bond the first optical waveguide layer 130 and the cover layer 110 in a vacuum environment and eliminate the air in the bonding surface of the first optical waveguide layer 130 and the cover layer 110.

[0069] In the above another embodiment, the adhesive layer 120 x is not disposed or filled between the first optical waveguide layer 130 and the cover layer 110 , and the first optical waveguide layer 130 and the cover layer 110 may be directly bonded together in a vacuum environment.

[0070] Specifically, the first optical waveguide layer 130 and the cover layer 110 are directly bonded under high vacuum conditions (vacuum degree <30pa), and no adhesive is used on the bonding surface, so that the first optical waveguide layer 130 and the cover layer 110 are in close contact, and the position of the grating 131 is not filled with an adhesive layer, thereby not affecting the optical properties. After the bonding is completed, the edges of the assembly obtained by bonding are bonded using an adhesive layer 120x under a vacuum state to ensure that no gas will penetrate between the first optical waveguide layer 130 and the cover layer 110.

[0071] The manufacturing process of the diffractive optical waveguide in the above embodiment may further include a bonding step, a gluing step and a curing step.

[0072] In the bonding step: under high vacuum conditions (vacuum degree <30 Pa), the first optical waveguide layer 130 and the cover layer 110 are bonded by mechanical pressure. After the bonding is completed, the first optical waveguide layer 130 and the cover layer 110 are tightly bonded under the action of atmospheric pressure to obtain a diffractive optical waveguide component. The bonding environment is a high vacuum environment, for example, a high vacuum environment of less than -10 Pa, and the bonding surface of the first optical waveguide layer 130 and the cover layer 110 has a relatively low surface roughness.

[0073] In the glue coating step: after the lens assembly is bonded, the peripheral edge of the area where the first light waveguide layer 130 and the cover layer 110 meet is sealed using a bonding layer 120X formed by liquid adhesive in a vacuum environment to ensure that air does not penetrate between the first light waveguide layer 130 and the cover layer 110, thereby preventing the lens assembly from cracking.

[0074] In the curing step: the lens assembly coated with liquid adhesive is cured by UV and / or heating to obtain an adhesive layer 120x disposed at the peripheral edge of the area where the first optical waveguide layer 130 and the cover layer 110 are connected, thereby increasing the reliability of the diffractive optical waveguide and the lens assembly.

[0075] like Fig. 9 In some other embodiments, the adhesive layer 120x is disposed at the peripheral edge and peripheral side area of ​​the area where the first light waveguide layer 130 and the cover layer 110 are connected. The adhesive layer 120x is used to bond the first light waveguide layer 130 and the cover layer 110 in a vacuum environment and eliminate the air in the bonding surface of the first light waveguide layer 130 and the cover layer 110.

[0076] According to the diffractive optical waveguide 100 of the embodiment of the present application, the adhesive layer 120x fully bonds the first optical waveguide layer 130 to the cover layer 110. Therefore, when the diffractive optical waveguide 100 is subjected to an external force, the relative deformation between the first optical waveguide layer 130 and the cover layer 110 is smaller, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide 100 transmits the signal light.

[0077] In the above-mentioned embodiment, the cover layer 110 is a protective layer, and the material of the protective layer can be resin, glass, or silicon wafer.

[0078] In the above embodiment, the cover layer 110 is the second optical waveguide layer, that is, the diffraction optical waveguide may include two or more optical waveguide layers, and the cover layer 110 is another optical waveguide layer different from the first optical waveguide layer 130 .

[0079] In the above embodiment, a first alignment mark is provided on the cover layer 110, and a second alignment mark corresponding to the first alignment mark is provided on the first optical waveguide layer 130. When the first optical waveguide layer 130 and the cover layer 110 are bonded together, the position of the first alignment mark and the position of the second alignment mark are identified by the image acquisition module, and the position deviation between the second alignment mark and the first alignment mark is obtained; based on the position deviation, the relative position of the first optical waveguide layer 130 and the cover layer 110 is compensated until the second alignment mark coincides with the first alignment mark. By using the image acquisition module to identify the first alignment mark and the second alignment mark, the position of the first optical waveguide layer 130 and the cover layer 110 can be accurately calibrated to ensure the alignment accuracy of the bonding of the first optical waveguide layer 130 and the cover layer 110.

[0080] The embodiment of the present application also provides a diffractive optical waveguide, Fig. 9Schematic diagram of the structure of another embodiment of the diffractive optical waveguide of the present invention. The diffractive optical waveguide 100 includes a covering layer 110, a first optical waveguide layer 130, and an adhesive layer 120x. The covering layer 110 has a first surface S1. The first optical waveguide layer 130 has a second surface S2, and the first optical waveguide layer 130 has a grating 131 on the second surface S2. The first optical waveguide layer 130 is attached and bonded to the covering layer 110 through the adhesive layer 120x, and the second surface S2 is arranged opposite to the first surface S1. The adhesive layer 120x is arranged at the outer peripheral edge of the area where the first optical waveguide layer 130 and the covering layer 110 are connected. The adhesive layer 120x is used to bond the first optical waveguide layer 130 and the covering layer 110 in a vacuum environment and eliminate the air in the bonding surface of the first optical waveguide layer 130 and the covering layer 110.

[0081] like Fig. 9 In this embodiment, the adhesive layer 120x is disposed at the peripheral edge and the peripheral side area of ​​the area where the first light waveguide layer 130 and the cover layer 110 are connected. In some embodiments, the first light waveguide layer 130 and the cover layer 110 have the same outer contour shape and size, and the adhesive layer 120x is disposed at the peripheral edge and the peripheral side area of ​​the area where the first light waveguide layer 130 and the cover layer 110 are connected, which can further improve the sealing between the first light waveguide layer 130 and the cover layer 110, and improve the bonding strength of the obtained lens assembly.

[0082] The present application also provides a near-eye display device. Fig.10 Schematic diagram of the cross-sectional structure of an embodiment of a near-eye display device of the present invention. The near-eye display device comprises an optical engine 200 and a diffractive optical waveguide 100 of any of the above-mentioned embodiments. The optical engine 200 is used to emit signal light. The diffractive optical waveguide 100 is used to transmit signal light.

[0083] In one example, the diffractive optical waveguide 100 includes a cover layer 110, a first optical waveguide layer 130, and an adhesive layer 120x. The cover layer 110 has a first surface S1. The first optical waveguide layer 130 has a second surface S2. The first optical waveguide is formed with a grating 131 on the second surface S2. The first optical waveguide layer 130 is attached and bonded to the cover layer 110 through the adhesive layer 120x. The second surface S2 is arranged opposite to the first surface S1. The surface of the adhesive layer 120x facing away from the cover layer 110 has a groove 121, and the grating 131 corresponds to the position of the groove 121, so that there is a gap between the grating 131 and the surface of the adhesive layer 120x.

[0084] The near-eye display device is, for example, augmented reality (AR) glasses or a part of AR glasses.

[0085] According to the near-eye display device of the embodiment of the present application, it includes a diffractive optical waveguide 100, wherein the adhesive layer 120x fully bonds the first optical waveguide layer 130 to the cover layer 110. Therefore, when the diffractive optical waveguide 100 is subjected to an external force, the relative deformation between the first optical waveguide layer 130 and the cover layer 110 is smaller, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide 100 transmits the signal light.

[0086] According to the near-eye display device of the above example, the adhesive layer 120x of the diffractive optical waveguide 100 fully bonds the first optical waveguide layer 130 and the cover layer 110, and most of the area between the first optical waveguide layer 130 and the cover layer 110 is filled by the adhesive layer 120x, thereby eliminating most of the gap between the first optical waveguide layer 130 and the cover layer 110. Therefore, even if the diffractive optical waveguide 100 is subjected to an external force, the relative deformation between the first optical waveguide layer 130 and the cover layer 110 is smaller due to the filling effect of the adhesive layer 120x, thereby improving the stability and reliability of the display effect after the diffractive optical waveguide 100 transmits the signal light. There is a gap between the grating 131 and the surface of the adhesive layer 120x, so that during the manufacturing process of the diffraction optical waveguide 100, the adhesive layer used to form the adhesive layer 120x will not penetrate into the grating 131 on the first optical waveguide layer 130, thereby preventing the adhesive layer from penetrating into the grating 131 and affecting the grating 131. Since the adhesive layer will not penetrate into the grating 131, the refractive index of the adhesive layer is no longer restricted when selecting the material, thereby reducing the material requirements for the adhesive layer.

[0087] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made under the concept of the present application using the contents of the present application specification and drawings, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a diffractive optical waveguide, characterized in that: include: forming a liquid adhesive layer on the first surface of the cover layer; pre-curing the liquid adhesive layer so that the liquid adhesive layer is transformed into a pre-cured layer; patterning the pre-cured layer to form a groove on a surface of the pre-cured layer facing away from the cover layer; Laminating a first optical waveguide layer having a grating to the cover layer through the pre-cured layer, wherein a second surface of the first optical waveguide layer having the grating is arranged opposite to the first surface, and the grating corresponds to the position of the groove; The pre-cured layer is cured so that the pre-cured layer is transformed into a solid adhesive layer and bonds the first optical waveguide layer to the cover layer.

2. The method for manufacturing a diffractive optical waveguide according to claim 1, wherein: The forming of a liquid adhesive layer on the first surface of the cover layer comprises: A liquid adhesive layer with uniform thickness is formed on the first surface of the covering layer by electrostatic adsorption coating, electromagnetic adsorption coating or centrifugal force coating.

3. The method for manufacturing a diffractive optical waveguide according to claim 1, characterized in that: The pre-curing of the liquid adhesive layer so that the liquid adhesive layer is transformed into a pre-cured layer comprises: The liquid adhesive layer is subjected to a viscosity-enhancing treatment to obtain a pre-cured layer capable of maintaining a constant shape under an external force within a preset range.

4. The method for manufacturing a diffractive optical waveguide according to claim 1, wherein: The patterning of the pre-cured layer to form a groove on a surface of the pre-cured layer away from the cover layer comprises: Disposing a patterned mask on a side of the pre-cured layer away from the cover layer, wherein the patterned mask has a mask opening; Etching the pre-cured layer using the patterned mask to form a groove in a region of the pre-cured layer corresponding to the mask opening; The patterned mask is peeled off.

5. The method for manufacturing a diffractive optical waveguide according to claim 4, characterized in that: The etching depth of the pre-cured layer is 200 nm or less, so that the depth of the groove is 200 nm or less.

6. The method for manufacturing a diffractive optical waveguide according to claim 1, wherein: In the step of laminating the first optical waveguide layer having the grating to the cover layer through the pre-cured layer, the laminating pressure and laminating time are controlled so that the thickness of the pre-cured layer varies within 200 nm.

7. The method for manufacturing a diffractive optical waveguide according to claim 1, wherein: The covering layer is a protective layer; or The cover layer is a second optical waveguide layer.

8. A diffractive optical waveguide, characterized in that: The method for manufacturing a diffractive optical waveguide is obtained by the method according to any one of claims 1 to 7.

9. A diffractive optical waveguide, characterized in that: include: a cover layer having a first surface; A first optical waveguide layer having a second surface, wherein the first optical waveguide layer has a grating on the second surface; an adhesive layer, wherein the first optical waveguide layer is bonded to the cover layer through the adhesive layer, the second surface is arranged to face the first surface, the adhesive layer is arranged between the first optical waveguide layer and the cover layer or on the outer peripheral surface of the area where the first optical waveguide layer and the cover layer are in contact, and the adhesive layer is used to bond the first optical waveguide layer and the cover layer in a vacuum environment and eliminate air in the bonding surface of the first optical waveguide layer and the cover layer.

10. A diffractive optical waveguide, characterized in that: include: a cover layer having a first surface; A first optical waveguide layer having a second surface, wherein the first optical waveguide layer has a grating on the second surface; an adhesive layer, wherein the first optical waveguide layer is attached and bonded to the cover layer through the adhesive layer, the second surface is arranged to face the first surface, the adhesive layer is arranged between the first optical waveguide layer and the cover layer, a surface of the adhesive layer facing away from the cover layer has a groove, the grating corresponds to the position of the groove, so that there is a gap between the grating and the surface of the adhesive layer.

11. The diffractive optical waveguide according to claim 10, characterized in that: The depth of the groove is 0 to 200 nm.

12. The diffractive optical waveguide according to claim 10, characterized in that: The cover layer is a second optical waveguide layer.

13. The diffractive optical waveguide according to claim 10, wherein: A first alignment mark is disposed on the cover layer, and a second alignment mark corresponding to the first alignment mark is disposed on the first optical waveguide layer.

14. A diffractive optical waveguide, characterized in that: include: a cover layer having a first surface; A first optical waveguide layer having a second surface, wherein the first optical waveguide layer has a grating on the second surface; an adhesive layer, wherein the first optical waveguide layer is bonded to the cover layer through the adhesive layer, the second surface is arranged to face the first surface, the adhesive layer is arranged at the peripheral edge of the area where the first optical waveguide layer and the cover layer are connected, and the adhesive layer is used to bond the first optical waveguide layer and the cover layer in a vacuum environment and eliminate air in the bonding surface of the first optical waveguide layer and the cover layer.

15. The diffractive optical waveguide according to claim 14, characterized in that: The adhesive layer is provided at the outer peripheral edge and the outer peripheral side region of the region where the first optical waveguide layer and the cover layer are in contact.

16. A near-eye display device, characterized in that: include: An optical machine, used for transmitting signal light; as well as The diffractive optical waveguide according to any one of claims 8 to 15, used for transmitting the signal light.

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