Preparation method of light guide element master mask and light guide element master mask

Abstract

The embodiment of the invention discloses a preparation method of a light guide element master mask and the light guide element master mask. The preparation method comprises the following steps: providing at least two imprinting master masks, wherein the imprinting master masks comprise a plurality of first grating partitions with set optical functions; the imprinting mother set is adopted for imprinting, so that the multiple first grating subareas on the imprinting mother set are imprinted on an imprinting sheet, the imprinting sheet is segmented to form multiple independent second grating subareas, and patterns of the multiple second grating subareas correspond to patterns of the multiple first grating subareas in a one-to-one mode; and a plurality of second grating partitions are selected and combined together to form the first light guide element master mask.

Description

Technical Field

[0001] The present invention relates to the field of optical technologies, and more particularly, to a method for preparing a master mold of a light guiding element and a master mold of a light guiding element. Background Art

[0002] Light guiding elements, such as optical waveguides, are one of the mainstream solutions for current AR glasses. The preparation method thereof is as follows: First, grating parameters need to be determined through design simulation. Secondly, an optical waveguide master mold is prepared through processes such as photolithography, laser direct writing, and etching. Finally, an optical waveguide product is produced by using nanoimprint technology. The current mainstream master mold processing solution is to process an input grating, an output grating, or an input grating, a turning grating, and an output grating on one master mold according to the design to prepare a one-dimensional optical waveguide master mold or a two-dimensional optical waveguide master mold. The master mold processing process is difficult and time-consuming. Summary of the Invention

[0003] An object of the present invention is to provide a new technical solution for a method for preparing a master mold of a light guiding element.

[0004] According to one aspect of the present invention, there is provided a method for preparing a master mold of a light guiding element. The preparation method includes:

[0005] Providing at least two imprint master molds, where the imprint master molds include a plurality of first grating partitions having set optical functions;

[0006] Performing imprinting by using the imprint master molds to imprint the plurality of first grating partitions on the imprint master molds onto an imprint sheet, and dividing the imprint sheet to form a plurality of independent second grating partitions, where the patterns of the plurality of second grating partitions correspond one-to-one to the patterns of the plurality of first grating partitions;

[0007] Selecting a plurality of the second grating partitions and combining them together to form a first master mold of a light guiding element.

[0008] Optionally, the step of performing imprinting by using the imprint master molds to imprint the plurality of first grating partitions on the imprint master molds onto an imprint sheet, and dividing the imprint sheet to form a plurality of independent second grating partitions, where the patterns of the plurality of second grating partitions correspond one-to-one to the patterns of the plurality of first grating partitions includes:

[0009] Coating a first sub-film adhesive on the imprint master mold;

[0010] Performing imprinting on the first sub-film adhesive to obtain a first working soft film;

[0011] Providing a first substrate coated with an imprint adhesive, and using the first working soft film to imprint the imprint adhesive on the first substrate to form the imprint sheet.

[0012] Optionally, before the step of coating the first sub-film adhesive on the imprint master, the method further includes: performing an anti-sticking treatment on the imprint master.

[0013] Optionally, positioning marks are provided on the imprint master.

[0014] Optionally, the step of selecting a plurality of the second grating partitions and combining them together to form a first master light guide element includes:

[0015] Determining the rotation angle of the grating partition according to the grating orientation of the grating partition.

[0016] Optionally, the step of selecting a plurality of the second grating partitions and combining them together to form a first master light guide element includes:

[0017] Providing a bottom plate, the bottom plate being adapted to carry each of the second grating partitions;

[0018] Coating an adhesive on the surface of the bottom plate;

[0019] Bonding each of the second grating partitions to the adhesive and splicing each of the second grating partitions;

[0020] Curing the adhesive so that each of the second grating partitions is fixed on the bottom plate.

[0021] Optionally, the method further includes filling the gaps between the plurality of second grating partitions.

[0022] Optionally, the filling process includes:

[0023] Coating a filling adhesive on the plurality of second grating partitions, the filling adhesive filling the gaps;

[0024] Curing the filling adhesive;

[0025] Removing the filling adhesive on the side of the plurality of second grating partitions away from the bottom plate.

[0026] Optionally, before the step of curing the filling adhesive, the method includes:

[0027] Pressing the filling adhesive.

[0028] Optionally, the filling adhesive includes a second sub-film adhesive.

[0029] Optionally, the thickness of the bottom plate is 0.5 mm - 2 mm, and the coating thickness of the adhesive is less than or equal to 5 μm.

[0030] Optionally, the viscosity of the filling adhesive is less than or equal to 10 cPs, and / or

[0031] The hardness of the cured filling adhesive is less than or equal to 50D.

[0032] Optionally, it further includes:

[0033] Using the first master light guide element to imprint a second working soft film;

[0034] Providing a second substrate, and disposing an imprinting adhesive in each area of the second substrate corresponding to the pattern of each second grating partition of the first master light guide element;

[0035] Using the second working soft film to imprint the imprinting adhesive and curing the imprinting adhesive to form a second master light guide element.

[0036] Optionally, the step of selecting and combining a plurality of the second grating partitions together to form a first master light guide element includes:

[0037] Providing a blank sheet;

[0038] Combining the blank sheet with each of the second grating partitions to form the first master light guide element having a regular geometric shape.

[0039] According to another aspect of the present invention, there is provided a master light guide element prepared by the preparation method of the master light guide element according to any one of the above.

[0040] In the embodiment of the present invention, the preparation method of the master light guide element utilizes two or more imprinting master plates, divides a plurality of second grating partitions of an imprinting sheet prepared by the imprinting master plate, extracts the divided and independent plurality of second grating partitions, and forms a grating partition library; according to the design requirements of the master light guide element, selects appropriate second grating partitions in the grating partition library and recombines them into a first master light guide element. In this way, the second grating partitions of the newly designed first master light guide element can be found in the grating partition library, and can be directly combined and used, greatly simplifying the preparation process of the master light guide element, reducing the processing difficulty of the master light guide element, reducing the processing time, improving the yield rate, and also reducing the processing cost of the master light guide element.

[0041] Through the following detailed description of the exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings incorporated in and constituting a part of this specification illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0043] Figure 1It is a flowchart of a method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0044] Figure 2 It is a schematic diagram of a method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0045] Figure 3 It is a schematic diagram of another method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0046] Figure 4 It is a schematic diagram of yet another method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0047] Figure 5 It is a schematic diagram of angle adjustment for grating partitioning of a method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0048] Figure 6 It is a schematic diagram of a fourth method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0049] Figure 7 It is a schematic diagram of a fifth method for preparing a master mold of a light guide element according to an embodiment of the present invention.

[0050] Explanation of reference numerals

[0051] 10, slit; 20, filling glue; 30, pressing plate; 40, pressing roller; 50, positioning mark; 60, blank sheet. Detailed implementation manners

[0052] Now, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention.

[0053] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present invention or its application or use.

[0054] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification.

[0055] In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0056] It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0057] An embodiment of the present invention provides a method for preparing a master mold of a light guiding element. A light guiding element, for example, an optical waveguide, is a structure for guiding and transmitting light waves and is usually used in augmented reality devices. The following takes an optical waveguide as an example for illustration. The master mold of the light guiding element is, for example, a master mold of an optical waveguide.

[0058] The optical waveguide includes a one-dimensional optical waveguide and a two-dimensional optical waveguide. Among them, the grating partition of the one-dimensional optical waveguide includes an input grating and an output grating. The grating partition of the two-dimensional optical waveguide includes an input grating, an output grating, and a turning grating.

[0059] For the design of an optical waveguide, usually, each grating structure is designed on the same plane at the beginning of the design of the master mold of the light guiding element, and the positions of each grating structure are fixed. In the related art, the preparation process of the optical waveguide is as follows: First, use processes such as photolithography, laser direct writing, and etching to prepare the master mold of the light guiding element; then, transfer the grating structure on the master mold of the light guiding element to another medium, so as to obtain a working soft film with an uneven structure opposite to that of the grating structure of the master mold of the light guiding element; finally, use the working soft film to perform imprinting through nanoimprinting technology, and the required optical waveguide can be obtained. The structure of the master mold of the light guiding element is consistent with the grating structure of the optical waveguide. The preparation process for preparing the master mold of the light guiding element by processes such as photolithography, laser direct writing, and etching is complex, time-consuming, and has a low yield rate.

[0060] For a newly designed master mold of a light guiding element, there are cases where some grating partitions of the input grating, the turning grating, and the output grating are consistent with some grating partitions of the existing processed master mold. In this regard, an embodiment of the present invention provides a method for preparing a master mold of a light guiding element, which can extract the input grating, the turning grating, and the output grating on two or more existing processed master molds of the light guiding element to form a grating partition library, and when preparing a newly designed master mold of the light guiding element, select the required grating partitions from the grating partition library and recombine them into the required master mold of the light guiding element.

[0061] The following will Figures 1 to 7 describe in detail the method for preparing the master mold of the light guiding element according to the embodiment of the present invention.

[0062] According to an embodiment of the present invention, a method for preparing a master mold of a light guiding element is provided. As Figure 1 、 Figure 2 shown, the preparation method includes:

[0063] Providing at least two imprinting master molds, the imprinting master molds including a plurality of first grating partitions having set optical functions;

[0064] Perform imprinting using the imprint master to imprint multiple first grating partitions on the imprint master onto an imprint sheet, and divide the imprint sheet to form multiple independent second grating partitions. The patterns of the multiple second grating partitions correspond one-to-one with the patterns of the multiple first grating partitions;

[0065] Select multiple independent grating partitions and combine them together to form a master for a first light guiding element.

[0066] Specifically, the imprint master is a master formed by processes such as photolithography, laser direct writing, and etching. The material of the imprint master is glass, silicon, etc. The imprint master is used to imprint and form a first base soft film.

[0067] The imprint sheet is formed by imprinting a first working soft film using the imprint master and then imprinting an imprinting adhesive using the first working soft film. The imprint sheet generally includes a substrate and an imprinting adhesive bonded to the substrate. The first working soft film has a pattern that is a mirror image of the patterns of the multiple first grating partitions of the imprint master. By imprinting the imprinting adhesive using the first working soft film, a pattern identical to the patterns of the multiple first grating partitions of the imprint master is formed on the imprint sheet. In the embodiments of the present invention, the imprint sheet can be fabricated using the first working soft film, and the processing technology is simple and the processing difficulty is small. The imprint sheet is divided to form multiple independent second grating partitions. The multiple second grating partitions are respectively identical to the patterns of the multiple first grating partitions. This method can not only meet the optical requirements of the master for the first light guiding element, but also meet the convenience of the source of the second grating partitions.

[0068] Such as Figure 2As shown, in this example, the preparation method includes two imprint masters, namely the first imprint master and the second imprint master. The first grating partition of the first imprint master includes a first coupling grating a1 and a first output grating c1. The first grating partition of the second imprint master includes a second coupling grating a2, a turning grating b2, and a second output grating c2. According to the design requirements of the optical waveguide master, the patterns of the grating partitions of the first light guiding element master are respectively the same as the patterns of the first coupling grating a1, the turning grating b2, and the first output grating c1. The pattern has the ability to process light waves. Accordingly, two imprint sheets are prepared. In this way, the two imprint sheets are divided to form multiple independent second grating partitions. For example, the independent second grating partitions after division include a first coupling grating a1, a first output grating c1, a second coupling grating a2, a turning grating b2, and a second output grating c2. Then, according to the design requirements of the light guiding element master and the requirements for the positions and grating orientations of the respective grating partitions in the light guiding element master, the first coupling grating a1, the turning grating b2, and the first output grating c1 are spliced together to form the first light guiding element master. The first light guiding element master is used to prepare imprint sheet products. For example, the overall shape of the light guiding element master is circular. The spliced first light guiding element master is also circular. Among them, the grating orientation refers to the direction of the grating lines or the periodic structure. The grating orientation can be a horizontal orientation, a vertical orientation, or an inclined orientation.

[0069] In a specific embodiment of the present invention, a simulation software is used to determine the positions, shapes, and sizes of different grating partitions of the light guiding element master, so as to facilitate the cutting device to cut the imprint sheet to form second grating partitions with set shapes and sizes.

[0070] The simulation software is, for example, CAD software, CAXA software, etc. For example, CAD software is used to draw the imprint sheet and determine the shapes, positions, and sizes of the respective second grating partitions. Then, the drawn imprint sheet is imported into the dividing device and programmed. The dividing device is used to divide the imprint sheet to form multiple independent second grating partitions. In this way, it can effectively ensure that the size accuracy of each second grating partition after division is high. Optionally, the cutting device can be, but is not limited to, a CNC cutting device, a laser cutting device, etc.

[0071] In other examples, the second grating partitions having the same grating structure as the first light guiding element master include a first coupling grating a1 and a second output grating c2; or a first coupling grating a1, a turning grating b2, and a second output grating c2. During preparation, select the first coupling grating a1 and the second output grating c2 for splicing; or the first coupling grating a1, the turning grating b2, and the second output grating c2 for splicing.

[0072] Of course, the number of imprint masters and imprint sheets is not limited to two, and may also be three, four, five, or more. The first grating partition and the second grating partition are not limited to the above embodiments. In specific implementation, the second grating partitions of multiple imprint sheets can be divided, and the grating structures, dimensions, etc. of each second grating partition can be marked to form a grating partition library. When preparing the master of the light guide element, a suitable second grating partition can be selected from the grating partition library according to the design requirements of the master of the light guide element and spliced. The shape of the first master of the light guide element is not limited to a circle, and may also be a rectangle, trapezoid, rhombus, triangle, ellipse, semi-circle, etc. The shape of the grating partition is a rectangle, trapezoid, rhombus, triangle, ellipse, semi-circle, etc. Those skilled in the art can make a choice according to actual needs.

[0073] In a specific embodiment of the present invention, as Figure 3 shown, in this preparation method, first, according to the design requirements of the first master of the light guide element, the distances between the geometric centers of the first coupling grating a1, the turning grating b2, and the first output grating c1 are determined, that is, the distance L1 between the geometric centers of the first coupling grating a1 and the turning grating b2, the distance L2 between the geometric centers of the turning grating b2 and the first output grating c1, the distance L3 between the geometric centers of the first coupling grating a1 and the first output grating c1, and the included angles between the grating orientations of the three, that is, the included angle θ1 between the grating orientations of the first coupling grating a1 and the turning grating b2, the included angle θ2 between the grating orientations of the first coupling grating a1 and the first output grating c1, and the included angle θ3 between the grating orientations of the turning grating b2 and the first output grating c1; then, the first coupling grating a1, the turning grating b2, and the first output grating c1 are spliced together. This splicing method can make the positioning of each grating partition of the first master of the light guide element accurate, and the processing accuracy of the first master of the light guide element is high.

[0074] In the embodiment of the present invention, the preparation method of the master of the light guide element uses two or more imprint masters, divides the multiple second grating partitions of the imprint sheets prepared by the imprint masters, and extracts the divided and independent multiple second grating partitions to form a grating partition library; according to the design requirements of the master of the light guide element, a suitable second grating partition is selected from the grating partition library and recombined into the first master of the light guide element. In this way, the second grating partition of the newly designed first master of the light guide element can be found in the grating partition library, and the second grating partition can be directly combined and used, which greatly simplifies the preparation process of the master of the light guide element, reduces the processing difficulty of the master of the light guide element, reduces the processing time, improves the yield rate, and also reduces the processing cost of the master of the light guide element.

[0075] In one embodiment of the present invention, the step of performing imprinting using the imprint master to imprint a plurality of the first grating partitions on the imprint master onto an imprint sheet, and then dividing the imprint sheet to form a plurality of independent second grating partitions, where the patterns of the plurality of second grating partitions correspond one-to-one to the patterns of the plurality of first grating partitions, includes:

[0076] Coat a first sub-film adhesive on the imprint master;

[0077] Perform imprinting on the first sub-film adhesive to obtain a first working soft film;

[0078] Provide a first substrate coated with an imprinting adhesive, and use the first working soft film to imprint the imprinting adhesive on the first substrate to form the imprint sheet.

[0079] Specifically, during preparation, first, use processing techniques such as spin coating, spraying, and drop coating to coat the first sub-film adhesive onto the imprint master; then, use a nanoimprinting device to imprint the pattern on the imprint master onto the first sub-film adhesive. In this way, a pattern mirroring the pattern on the imprint master is formed on the first sub-film adhesive, and the first sub-film adhesive is cured to form a first working soft film. The first working soft film has a pattern mirroring the pattern on the imprint master; finally, use the first working soft film to imprint the imprinting adhesive to form the imprint sheet.

[0080] In this example, the first substrate is a hard material such as silicon, glass, or resin. When preparing the imprint sheet, first, coat the imprinting adhesive on the first substrate using processing techniques such as spin coating, spraying, and drop coating; then, use a nanoimprinting device to imprint the first working soft film on the imprinting adhesive; finally, cure the imprinting adhesive to form the imprint sheet. The imprint sheet has the same pattern as the pattern on the imprint master. That is, the patterns of the plurality of second grating partitions on the imprint sheet correspond one-to-one to the patterns of the plurality of first grating partitions on the imprint master.

[0081] When dividing the imprint sheet, place the imprint sheet in a cutting device and cut each second grating partition. The cutting device can be, for example, a laser cutting device, a CNC cutting device, etc. Optionally, positioning marks 50 are provided on the imprint sheet, and the cutting device positions the imprint sheet through the positioning marks 50 and then performs cutting. This setting method can effectively improve the division accuracy of the second grating partitions.

[0082] In one embodiment of the present invention, before the step of coating the first sub-film adhesive on the imprint master, it further includes: performing an anti-sticking treatment on the imprint master.

[0083] Specifically, processes such as spin coating, evaporation coating, and ion sputtering are used to perform anti - sticking treatment on the imprint master, and the effect of the anti - sticking treatment is judged by the water contact angle test. The anti - sticking treatment can effectively reduce the adhesion between the first sub - film glue and the imprint master, making the demolding of the first working soft film easier.

[0084] Of course, the method of anti - sticking treatment is not limited to the above - mentioned embodiments, and those skilled in the art can select according to actual needs.

[0085] In an embodiment of the present invention, positioning marks 50 are provided on the imprint master.

[0086] For example, positioning marks 50 are provided on the imprint master. After imprinting, positioning marks 50 with the same position and shape are formed on the imprinted sheet. The positioning marks 50 can be, but are not limited to, dots, rings, crosses, L - shapes, etc. The positioning marks 50 can be one or more. Optionally, the positioning marks 50 are three. The connection lines of the three positioning marks 50 form a right - angled triangle. This setting method can make the positioning of the grating partition in the cutting device more accurate.

[0087] Of course, the positioning marks 50 are not limited to the above - mentioned embodiments, and those skilled in the art can select according to actual needs.

[0088] In an embodiment of the present invention, the step of combining multiple second grating partitions together to form the master of the first light - guiding element includes:

[0089] Determining the rotation angle of the grating partition according to the grating orientation of the grating partition.

[0090] In this example, as Figure 5 shown, taking the first coupling grating a1 as an example for illustration. The first coupling grating a1 is rectangular. The grating orientation of the grating partition of the designed master of the first light - guiding element rotates clockwise by θ relative to the first grating partition with the same grating structure on the imprint master. Then, when preparing the master of the first light - guiding element, the second grating partition needs to be rotated by θ. If it is necessary to rotate the divided first coupling grating a1 clockwise by θ, then when dividing the imprinted sheet, the whole of the first coupling grating a1 needs to be rotated counterclockwise by θ to ensure that after rotating clockwise by θ during splicing, the rectangular first coupling grating a1 is placed in the correct orientation. The correct - orientation placement makes the splicing of each second grating partition regular, not prone to skew, and the gap 10 between adjacent second grating partitions is regular.

[0091] Of course, the magnitude of the rotation angle θ is not limited herein, and those skilled in the art can select according to actual needs.

[0092] In one embodiment of the present invention, the step of selecting and combining multiple of the second grating partitions together to form a master template of the first light guiding element includes:

[0093] Providing a bottom plate, the bottom plate being adapted to carry each of the second grating partitions;

[0094] Coating an adhesive on the surface of the bottom plate;

[0095] Bonding each of the second grating partitions on the adhesive and splicing each of the second grating partitions;

[0096] Curing the adhesive to fix each of the second grating partitions on the bottom plate.

[0097] In this example, as Figure 6 shown, the material of the bottom plate is a hard material such as glass, silicon, resin, etc. The shape of the bottom plate is circular, rectangular, trapezoidal, elliptical, triangular, semi-circular, etc. The bottom plate is used to carry each second grating partition. The adhesive is, for example, a UV adhesive or a thermosetting adhesive. In order to ensure the uniformity of the adhesive coating, the spin coating or spraying method is used to coat the surface of the bottom plate. Then, each of the second grating partitions is sequentially attached to the adhesive. For example, the CCD recognition system and the manipulator of the bonding equipment are used to place multiple second grating partitions on the carrier plate of the bonding equipment, and they are recognized through the software recognition system of the bonding equipment. Then, the manipulator is used to sequentially grab the second grating partitions and place them on the bottom plate for splicing; next, the adhesive is cured by UV irradiation or heating to fix each of the second grating partitions on the bottom plate. Finally, the spliced master template of the first light guiding element is formed.

[0098] In one embodiment of the present invention, the preparation method further includes a filling process for the gap 10 between multiple of the second grating partitions.

[0099] The gap 10 between multiple second grating partitions will form a raised structure on the working soft film during embossing. When using the working soft film to emboss the embossing sheet, a pit will be formed at the position corresponding to the raised structure, resulting in an uneven surface of the embossing sheet. This pit affects the optical effect of the optical waveguide and causes poor appearance. Through the filling process, the gap 10 can be effectively filled, so that the surface between the second grating partitions adjacent to the pattern side of the master template of the first light guiding element is flat, improving the optical effect and maintaining good appearance.

[0100] In one embodiment of the present invention, the filling process includes:

[0101] Coating a filling adhesive 20 on multiple of the second grating partitions, and the filling adhesive 20 fills the gap 10;

[0102] Cure the filling glue 20.

[0103] Remove the filling glue 20 on the side of the multiple second grating partitions facing away from the bottom plate.

[0104] In this example, the filling glue 20 is coated on the surfaces of the multiple second grating partitions. The filling glue 20 can fill the gaps 10 and cover the surfaces of the multiple second grating partitions. The filling glue 20 is, for example, UV glue, thermosetting glue, etc. The filling glue 20 is cured by means such as UV irradiation, heating, etc. The filling glue 20 covering the surfaces of the multiple second grating partitions is removed, and the filling glue 20 located in the gaps 10 is retained. The gaps 10 can be effectively filled by the filling glue 20, so that the surfaces between the second grating partitions adjacent to the patterned side of the first light guide element master are flat. The filling glue 20 can be bonded to the adjacent second grating partitions, improving the structural strength of the first optical waveguide structure.

[0105] The process of this filling treatment is simple, easy to operate, and the filling effect of the gaps 10 is good.

[0106] Of course, the filling treatment is not limited to the above embodiments, and those skilled in the art can make selections according to actual needs.

[0107] In an embodiment of the present invention, before the step of curing the filling glue 20, it includes:

[0108] Press the filling glue 20.

[0109] In this example, as Figure 6 shown, first, the filling glue 20 is coated on the multiple second grating partitions by means of spin coating or spraying. Then, the pressing plate 30 is covered on the filling glue 20, and a pressing roller 40 is used to roll from one side of the pressing plate 30 to the other side. The rolling makes the filling glue 20 more effectively fill the gaps 10, avoiding the phenomenon of lack of glue in the gaps 10.

[0110] Of course, the pressing method is not limited to rolling, and those skilled in the art can make selections according to actual needs.

[0111] In an embodiment of the present invention, the filling glue 20 includes a second sub-film glue.

[0112] The second sub-film glue is used to prepare a working soft film. In this example, the second sub-film glue can be, but is not limited to, polydimethylsiloxane, acrylic glue, silica gel, epoxy resin glue, etc. The second sub-film glue has a wide source and is easy to prepare. The working soft film after the filling glue 20 is separated from the second grating partition can also be used to prepare an imprinting sheet.

[0113] In an embodiment of the present invention, the thickness of the bottom plate is 0.5 mm - 2 mm, and the coating thickness of the adhesive is less than or equal to 5 μm.

[0114] In this example, a bottom plate with a thickness range of 0.5 mm - 2 mm is selected to carry the second grating partition. If the thickness of the bottom plate is too small, the structural strength is too low and it is easy to break; if the thickness is too large, the weight of the master plate of the first light guide element is too large, which is not convenient for imprinting. Within the above thickness range, the bottom plate has high structural strength and the weight of the prepared master plate of the first light guide element is moderate. Optionally, the thickness of the bottom plate is 0.5 mm, 0.7 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc.

[0115] When coating the adhesive, control its thickness to be less than or equal to 5 μm. If the thickness of the adhesive is too large, it is easy to cause poor thickness uniformity of the adhesive, and the thickness of each part is inconsistent. When the thickness of the adhesive is less than or equal to 5 μm, the adhesive is easy to maintain uniform thickness, so that the flatness of multiple second grating partitions is high. Optionally, the thickness of the adhesive is 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, etc.

[0116] In an embodiment of the present invention, the viscosity of the filling glue 20 is less than or equal to 10 cPs, and / or

[0117] The hardness of the cured filling glue 20 is less than or equal to 50 D.

[0118] In this example, the filling glue 20 is the second sub-film glue. The viscosity of the second sub-film glue is less than or equal to 10 cPs. If the viscosity of the second sub-film glue is too high, the fluidity becomes poor, and it is easy to cause the phenomenon of lack of glue in the gap 10. When the viscosity of the second sub-film glue is less than or equal to 10 cPs, the viscosity of the second sub-film glue is moderate and the bonding force is strong. Optionally, the viscosity of the second sub-film glue is 1 cPs, 2 cPs, 4 cPs, 5 cPs, 8 cPs, 10 cPs, etc.

[0119] The hardness of the cured second sub-film glue is less than or equal to 50 D. If the hardness of the second sub-film glue is too high, when the cured second sub-film glue is separated from multiple second grating partitions, it is easy to take out the second sub-film glue filled in the gap 10 together, so that it cannot be retained in the gap 10. When the hardness of the cured filling glue 20 is less than or equal to 50 D, during separation, the cured second sub-film glue can be disconnected from the sub-film glue in the gap 10, so that the second sub-film glue can be effectively retained in the gap 10.

[0120] Of course, the filling glue 20 is not limited to the second sub-membrane glue, and can also be melamine formaldehyde resin glue, furan resin glue, phenolic resin glue, etc. Those skilled in the art can refer to the above numerical range and make a selection according to actual needs.

[0121] In one embodiment of the present invention, the preparation method further comprises:

[0122] Using the first light guide element master to emboss and form a second working soft film;

[0123] Providing a second substrate, and disposing embossing glue in each area of ​​the second substrate corresponding to each pattern of the second grating subareas of the first light guide element master;

[0124] The embossing adhesive is embossed with the second working soft film, and the embossing adhesive is cured to form a second light guide element master.

[0125] In this example, if Figure 7 As shown, in order to reduce the adverse effects of the gap 10 of the first light guide element master, an inkjet dispensing process is used for secondary processing. First, the third sub-film glue is coated on the multiple second grating partitions of the first light guide element master, and a second working soft film is formed by a nano-imprinting process. The second working soft film has a pattern that is a mirror image of the pattern of the first light guide element master. The third sub-film glue can be made of the same material as the first sub-film glue.

[0126] Then, embossed glue is arranged on the second substrate. The material of the second substrate is the same as that of the first substrate. The position, shape and size of the embossed glue are the same as the position, shape and size of the pattern area of ​​each second grating partition of the first light guide element master. In order to improve the coating accuracy of the embossed glue, the embossed glue is arranged on the second substrate by using an inkjet dispensing process. The number of embossed glue is the same as the number of second grating partitions of the first light guide element master. After inkjet dispensing, the embossed glue can cover the pattern of the second grating partition without covering the edge area around the pattern.

[0127] Next, a nanoimprint device is used to imprint the pattern of the second working soft film on the imprint adhesive, and the imprint adhesive is cured. The cured imprint adhesive is fixed to the second substrate, and a grating structure identical to the pattern of the first light guide element master is formed on the side away from the second substrate. The second substrate and the cured imprint adhesive together constitute the second light guide element master.

[0128] The second light guide element master has no edge outside the pattern of the grating area, so that the gap 10 is formed due to the edge during embossing. In this way, the defect of pits between the grating areas formed by the first light guide element master with the gap 10 during embossing is effectively solved.

[0129] In one embodiment of the present invention, the step of selecting and combining a plurality of the second grating partitions together to form a master mold of a first light guiding element includes:

[0130] Providing a blank sheet 60;

[0131] Combining the blank sheet 60 with each of the grating partitions to form the master mold of the first light guiding element having a regular geometric shape.

[0132] In this example, in order to ensure that the overall surface of the grating side of the master mold of the first light guiding element is uniform and the thickness of the imprinting adhesive remains uniform during imprinting, in addition to splicing a plurality of second grating partitions, it is also necessary that a plurality of grating regions form a regular shape after splicing, such as a circle, a rectangle, an isosceles trapezoid, an ellipse, a regular hexagon, a regular octagon, etc. To achieve the above technical effects, during the splitting, a plurality of second grating partitions can be split into regular shapes such as rectangles, semi - circles, etc. The above - mentioned shapes are convenient for splicing into regular shapes. In addition, a blank sheet 60 is provided at the vacancy after splicing a plurality of second grating partitions. The blank sheet 60 can fill the vacancy, thereby making the whole of the second grating partitions regular. The shape of the blank sheet 60 can be, but is not limited to, a rectangle, a circle, a trapezoid, a semi - circle, a triangle, etc.

[0133] As Figure 4 shown, the first coupling grating a1, the turning grating b2, and the first output grating are all rectangles. After splicing, a vacancy is formed in the upper right corner. As Figure 6 shown, a blank sheet 60 is provided at this vacancy. The thickness of the blank sheet 60 is the same as that of the first coupling grating a1, the turning grating b2, and the first output grating, thereby filling this vacancy. Finally, a regular rectangular grating structure is formed. In this example, by providing the blank sheet 60, the grating structure can be made regular, so that the surface of the grating structure is uniform and the thickness of the imprinting adhesive is uniform during imprinting.

[0134] According to the second embodiment of the present invention, a master mold of a light guiding element is provided. The master mold of the light guiding element is prepared by the preparation method of the master mold of the light guiding element provided by the present invention.

[0135] The master mold of the light guiding element is, for example, a master mold of an optical waveguide. The master mold of the light guiding element has the characteristics of simple processing technology and high yield.

[0136] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration purposes and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for preparing a light guide element master, characterized in that: include: providing at least two imprint masters, the imprint masters comprising a plurality of first grating divisions having a set optical function; Using the imprint master to perform imprinting, so as to imprint the plurality of first grating divisions on the imprint master onto an imprint sheet, and dividing the imprint sheet to form a plurality of independent second grating divisions, wherein the patterns of the plurality of second grating divisions correspond one to one to the patterns of the plurality of first grating divisions; A plurality of the second grating divisions are selected and combined together to form a first light guide element master.

2. The method for preparing a light guide element master according to claim 1, characterized in that: The step of using the imprint master to perform imprinting to imprint the plurality of first grating divisions on the imprint master onto an imprint sheet, dividing the imprint sheet to form a plurality of independent second grating divisions, wherein the patterns of the plurality of second grating divisions correspond one-to-one to the patterns of the plurality of first grating divisions comprises: Coating a first sub-film glue on the imprint master; embossing the first sub-film to obtain a first working soft film; A first substrate is provided, wherein an embossing adhesive is coated on the first substrate, and the embossing adhesive on the first substrate is embossed with the first working soft film to form the embossed sheet.

3. The method for preparing a light guide element master according to claim 2, characterized in that: Before the step of coating the first sub-film glue on the imprint master, the method further includes: performing anti-sticking treatment on the imprint master.

4. The method for preparing a light guide element master according to claim 1, characterized in that: A positioning mark is arranged on the imprint master.

5. The method for preparing a light guide element master according to claim 1, characterized in that: The step of selecting a plurality of the second grating partitions and combining them together to form a first light guide element master comprises: The rotation angle of the grating subregion is determined as a function of the grating course of the grating subregion.

6. The method for preparing a light guide element master according to claim 1, characterized in that: The step of selecting a plurality of the second grating partitions and combining them together to form a first light guide element master comprises: Providing a base plate, the base plate being suitable for carrying each of the second grating sub-areas; Applying adhesive on the surface of the base plate; Adhere each of the second grating sub-areas to the adhesive, and splice each of the second grating sub-areas; The adhesive is cured to fix each of the second grating subareas on the base plate.

7. The method for preparing a light guide element master according to claim 6, characterized in that: The method also includes filling gaps between the plurality of second grating partitions.

8. The method for preparing a light guide element master according to claim 7, characterized in that: The filling process includes: Applying a filling glue on the plurality of second grating subareas, wherein the filling glue fills the gaps; curing the filling glue; The filling glue located on a side of the plurality of second grating partitions away from the bottom plate is removed.

9. The method for preparing a light guide element master according to claim 8, characterized in that: Before the step of curing the filling glue, the method includes: The filling glue is pressed.

10. The method for preparing a light guide element master according to claim 8, characterized in that: The filling glue includes a second sub-film glue.

11. The method for preparing a light guide element master according to claim 6, characterized in that: The thickness of the bottom plate is 0.5 mm-2 mm, and the coating thickness of the adhesive is less than or equal to 5 μm.

12. The method for preparing a light guide element master according to claim 8, characterized in that: The viscosity of the filling glue is less than or equal to 10 cPs, and / or The hardness of the filling glue after curing is less than or equal to 50D.

13. The method for preparing a light guide element master according to claim 1, characterized in that: Also includes: Using the first light guide element master to emboss and form a second working soft film; Providing a second substrate, and disposing embossing glue on each area of ​​the second substrate corresponding to each pattern of the second grating subareas of the first light guide element master; The embossing adhesive is embossed with the second working soft film, and the embossing adhesive is cured to form a second light guide element master.

14. The method for preparing a light guide element master according to claim 1, characterized in that: The step of selecting a plurality of the second grating partitions and combining them together to form a first light guide element master comprises: Provide blank sheets; The blank sheet is combined with each of the second grating divisions to form the first light guide element master having a regular geometric shape.

15. A light guide element motherboard, characterized in that: The light guide element master is prepared according to the method for preparing the light guide element master as described in any one of claims 1 to 14.

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