Waveguide and preparation parameter determination method thereof, preparation method and head-up display equipment

Abstract

The invention relates to a waveguide, a method for determining preparation parameters of the waveguide, a preparation method of the waveguide and head-up display equipment. The waveguide comprises a coupling-out unit. The out-coupling unit comprises a plurality of out-coupling gratings, and the outlines of the out-coupling gratings are trapezoidal. The coupling-out grating comprises periodically arranged line-shaped structures, the extension direction of the line-shaped structures is parallel to the extension direction of the bottom edges of the trapezoids, the arrangement direction of the line-shaped structures is perpendicular to the extension direction of the bottom edges of the trapezoids, and the fitting error between the geometric gravity centers of the trapezoids and the target fitting curve is smaller than 10-4 mm; the target fitting curve is a quadratic fitting curve of geometric gravity centers of a plurality of trapezoids. The waveguide provided by the invention has stronger line focusing capability, and can improve the problem of light deflection, thereby reducing aberration and improving imaging quality. And light deflection can be avoided without adding an additional phase compensation sheet or setting an additional phase compensation mechanism, so that the preparation cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of waveguide application to head-up display, and in particular to a method for determining waveguide and preparation parameters thereof, a preparation method, and a head-up display device. Background Art

[0002] In the field of Head-Up Display (HUD) technology, display information is usually projected into the user's field of view via a waveguide.

[0003] The waveguide projects light from the light source to the windshield, which then transmits the light to the user's field of view. Since the curved windshield causes light to bend, a typical HUD places a free-form surface on the last element that emits light to correct this deflection.

[0004] However, there is no correction mechanism for the light emitted by the general grating waveguide, which leads to the generation of aberrations. Summary of the invention

[0005] Based on this, it is necessary to provide a waveguide that can improve the aberration caused by light deflection, a method for determining its preparation parameters, a preparation method and a head-up display device in order to address the above technical problems.

[0006] In a first aspect, the present application provides a waveguide, the waveguide comprising an outcoupling unit; the outcoupling unit comprises a plurality of outcoupling gratings, and the outer contour of the outcoupling gratings is a trapezoid;

[0007] The outcoupling grating comprises a periodically arranged linear structure, wherein the extension direction of the linear structure is parallel to the extension direction of the bottom side of the trapezoid, and the arrangement direction of the linear structure is perpendicular to the extension direction of the bottom side of the trapezoid;

[0008] The fitting error between the geometric center of gravity of the multiple trapezoids and the target fitting curve is less than 10 -4 mm, the target fitting curve is a quadratic fitting curve of the geometric centroids of the multiple trapezoids, the upper bases of the multiple trapezoids are located on the same side of the quadratic fitting curve, and the upper base is the longer of the two bases of the trapezoid.

[0009] In one embodiment, the tangent angle corresponding to the difference between the curvature of the quadratic fitting curve and the target curvature is less than 0.3 degrees.

[0010] In one embodiment, at least two adjacent outcoupling gratings have a gap with a gradually varying width.

[0011] In one embodiment, the width of the gap on a side close to the upper base of the trapezoid is smaller than the width of the gap on a side close to the lower base of the trapezoid.

[0012] In a second aspect, the present application provides a method for determining waveguide preparation parameters, which is used to determine the preparation parameters of the waveguide as described above; the waveguide includes an outcoupling unit provided with a plurality of outcoupling gratings; the method for determining the waveguide preparation parameters includes:

[0013] Acquire a corresponding mathematical model according to the propagation characteristics of the light transmitted through the waveguide to the target position;

[0014] The number of the out-coupling gratings is determined as a target number according to the mathematical model and the size of the preset master mold; and the outer contour of the out-coupling grating is a trapezoid.

[0015] In one embodiment, the waveguide further includes a coupling unit; the step of obtaining a corresponding mathematical model according to the propagation characteristics of the light transmitted through the waveguide to the target position includes:

[0016] Acquire first light information of the light on the plane where the coupling unit is located;

[0017] Obtaining second light information on the plane where the light is located at the target position;

[0018] The mathematical model is acquired according to the first light information and the second light information.

[0019] In one embodiment, the mathematical model is:

[0020] U=A(1)+A(2)X+A(3)Y+A(4)XY+A(5)X 2 +A(6)Y 2 ;

[0021] V=B(1)+B(2)X+B(3)Y+B(4)XY+B(5)X 2 +B(6)Y 2 ;

[0022] Wherein, U and V are the first light information of the light in the plane where the coupling-in unit is located; X and Y are the second light information of the light coupled out by the coupling-out unit in the plane where the target position is located; A(1) is a preset basic displacement item corresponding to the position information in the U direction in the first light information; A(2) and A(3) are preset slope items corresponding to the position information in the U direction in the first light information; A(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the U direction in the first light information; A(5) and A(6) are preset slope change items corresponding to the position information in the U direction in the first light information; B(1) is a preset basic displacement item corresponding to the position information in the V direction in the first light information; B(2) and B(3) are preset slope items corresponding to the position information in the V direction in the first light information; B(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the V direction in the first light information; B(5) and B(6) are preset slope change items corresponding to the position information in the V direction in the first light information.

[0023] In one embodiment, the target number includes the number of the outcoupling gratings in the first direction and the number of the outcoupling gratings in the second direction; the second direction is perpendicular to the second direction; the formula for determining the number of the outcoupling gratings as the target number according to the mathematical model and the size of the preset master mold is:

[0024] D1=floor(2*(B(5)+B(6))*W / h);

[0025] D2=floor(2*(A(5)+A(6))*W / h);

[0026] Wherein, D1 is the number of the outcoupling gratings in the first direction; D2 is the number of the outcoupling gratings in the second direction; W is the target size of the outcoupling unit in the first direction; h is the target size of the outcoupling unit in the second direction and the size of the preset master mold in the second direction; floor is an unconditional carry operation function symbol.

[0027] In one embodiment, the waveguide further includes a coupling unit and a spreading unit; and the method for determining the waveguide preparation parameters further includes:

[0028] The relative position parameters between the out-coupling unit, the spreading unit and the coupling-in unit are obtained according to the prepared out-coupling unit, so that the coupling-in unit receives the light at a target angle and transmits the light to the spreading unit, and the spreading unit projects the received light to the target position in at least part of the out-coupling grating.

[0029] In a third aspect, the present application provides a method for preparing a waveguide, wherein the waveguide is the waveguide as described above; the waveguide includes an outcoupling unit, and the outcoupling unit includes a plurality of outcoupling gratings; the method for preparing the waveguide includes:

[0030] Reprinting a preset master mold according to the preparation parameters determined by the above-mentioned method for determining waveguide preparation parameters to obtain a coupling-out master mold containing a target number of the coupling-out gratings;

[0031] The waveguide is prepared based on the decoupled master mold.

[0032] In one embodiment, the step of preparing the waveguide based on the out-coupling master mold comprises:

[0033] Acquire a waveguide master mold based on the outcoupled master mold;

[0034] Performing plate-building and mold-expanding on the waveguide master mold to obtain a waveguide plate-building;

[0035] Transfer printing the waveguide imposition plate to obtain a plurality of working molds;

[0036] A plurality of the working molds are cut and assembled to obtain the waveguide.

[0037] In a fourth aspect, the present application provides a head-up display device, comprising a waveguide as described above; or, comprising a waveguide as described above.

[0038] The waveguide and the method for determining the preparation parameters thereof, the preparation method and the head-up display device, the waveguide includes a coupling unit; the coupling unit includes a plurality of coupling gratings, the outer contour of the coupling grating is a trapezoid; the coupling grating includes a periodically arranged linear structure, the extension direction of the linear structure is parallel to the extension direction of the bottom side of the trapezoid, and the arrangement direction of the linear structure is perpendicular to the extension direction of the bottom side of the trapezoid, and the fitting error between the geometric center of gravity of the plurality of trapezoids and the target fitting curve is less than 10 -4 mm, the target fitting curve is a quadratic fitting curve of the geometric center of gravity of multiple trapezoids. In the present application, the outer contour of the outcoupling grating is a trapezoid, and multiple outcoupling gratings form an outcoupling unit, which means that the outcoupling unit can form an ideal parabolic light reflection structure, can focus parallel light rays to one point, has a stronger line focusing ability, can improve the problem of light deflection, thereby reducing aberrations and improving imaging quality. And the present application can avoid light deflection without adding additional phase compensation plates or setting additional phase compensation mechanisms, thereby reducing the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions 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 related drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 is a schematic structural diagram of a coupling-out unit in an embodiment of the present application;

[0041] Figure 2 is a schematic diagram of a quadratic fitting curve of the geometrical centroids of a plurality of outcoupling gratings in an embodiment of the present application;

[0042] Figure 3 Schematic diagram of a flow chart of a method for determining waveguide preparation parameters in an embodiment of the present application;

[0043] Figure 4 It is a transmission simulation schematic diagram of light transmitted to a target position through a waveguide in one embodiment of the present application;

[0044] Figure 5 A schematic diagram of a simulation of light distribution on a plane where a coupling unit is located in an embodiment of the present application;

[0045] Figure 6 is a schematic diagram of the structure of a waveguide in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of a process of replicating a preset master mold to obtain a coupling-out master mold containing a target number of coupling-out gratings in one embodiment of the present application;

[0047] Figure 8 This is one of the schematic diagrams of the process of preparing a waveguide based on a coupled-out mother mold in one embodiment of the present application;

[0048] Fig. 9 This is the second schematic diagram of the process of preparing a waveguide based on a coupled-out mother mold in one embodiment of the present application.

[0049] Description of Figure Numbers:

[0050] 100: waveguide; 110: decoupling unit; 111: decoupling grating; 1111: preset master mold; 1112: decoupling master mold; 120: coupling unit; 130: dimension expansion unit; 200: windshield; 901: waveguide master mold; 902: waveguide panel; 903: replica mold; 904: working mold. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0052] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] See also Figures 1-2 , Figure 1 FIG. 1 shows a schematic diagram of the structure of the coupling-out unit 110 in an embodiment of the present application. Figure 2 FIG. 1 shows a schematic diagram of a quadratic fitting curve of the geometric center of gravity G of multiple outcoupling gratings 111 in an embodiment of the present application, wherein FIG. Figure 1 and attached Figure 2The number of outcoupling gratings 111 is 4 for illustration. An embodiment of the present application provides a waveguide, which includes an outcoupling unit 110. The outcoupling unit 110 includes a plurality of outcoupling gratings 111, and the outer contour of the outcoupling gratings 111 is a trapezoid. The outcoupling gratings 111 include periodically arranged linear structures, the extension direction of the linear structures is parallel to the extension direction of the bottom side of the trapezoid, and the arrangement direction of the linear structures is perpendicular to the extension direction of the bottom side of the trapezoid.

[0056] Among them, the fitting error between the geometric center of gravity G of multiple trapezoids and the target fitting curve is less than 10 -4 mm, the target fitting curve is a quadratic fitting curve of the geometric centroid G of the multiple trapezoids, the upper bases of the multiple trapezoids are located on the same side of the quadratic fitting curve, and the upper base is the longer of the two bases of the trapezoids.

[0057] The outcoupling unit 110 of the waveguide is used to transmit the light to a target location along a specific path, for example, to a windshield, so that the windshield further projects the light into the user's field of vision.

[0058] The number of out-coupling gratings 111 in the waveguide can be determined according to the propagation characteristics of the light transmitted to the target position through the waveguide. The number of out-coupling gratings 111 is related to the curvature of the quadratic fitting curve of the geometrical centroid G of the plurality of trapezoids. The out-coupling gratings 111 in the embodiment of the present application include a periodically arranged linear structure, the extension direction of the linear structure is parallel to the extension direction of the bottom side of the trapezoid, and the arrangement direction of the linear structure is perpendicular to the extension direction of the bottom side of the trapezoid, and the fitting error between the geometrical centroid G of the plurality of trapezoids and the target fitting curve is less than 10 -4 mm, thus ensuring that the outcoupling unit 110 in the embodiment of the present application can form an ideal parabolic light reflection structure, can focus parallel light rays to one point, has a stronger line focusing ability, can improve the light deflection problem, thereby reducing aberrations and improving imaging quality. And it is possible to avoid light polarization without adding an additional phase compensation plate or setting an additional phase compensation mechanism, thereby reducing the manufacturing cost.

[0059] In addition, the coupling unit 110 in the embodiment of the present application is composed of a plurality of coupling gratings 111 with a trapezoidal outer contour. During preparation, there is no need to demold and emboss the coupling unit 110 with a large volume or a large area, which reduces the production difficulty and improves the preparation efficiency.

[0060] In one embodiment, a tangent angle corresponding to a difference between the curvature of the quadratic fitting curve and the target curvature is less than 0.3 degrees.

[0061] The relationship between the curvature difference and the angle can be converted by the formula Δκ=dθ1 / ds-dθ2 / ds=d(θ1-θ2) / ds. Where d is the differential calculation symbol, s is the arc length parameter of the curve, (θ1-θ2) is the tangent angle difference between the two curves, and Δκ is the difference between the curvature of the quadratic fitting curve and the target curvature.

[0062] In this embodiment, the target curvature is associated with the propagation characteristics of light transmitted through the waveguide to the target position. The tangent angle corresponding to the difference between the curvature of the quadratic fitting curve and the target curvature is less than 0.3 degrees, which can ensure that the structure of the coupling unit 110 is consistent with the propagation characteristics of light transmitted through the waveguide to the target position. At this time, the light propagation performance of the coupling unit 110 is relatively high, which can improve the problem of light deflection.

[0063] In one embodiment, at least two adjacent outcoupling gratings have a gap with a gradually varying width therebetween.

[0064] In this embodiment, there are gaps with gradually varying widths between adjacent outcoupling gratings, which can improve the adjustment accuracy of the quadratic fitting curve fitted by the geometrical centroids of the multiple trapezoids, and ensure that the fitting error between the geometrical centroids of the multiple trapezoids and the target fitting curve is less than 10 -4 mm.

[0065] In one embodiment, the width of the gap on a side close to the upper base of the trapezoid is smaller than the width of the gap on a side close to the lower base of the trapezoid.

[0066] In this embodiment, the width of the gap close to the upper base of the trapezoid is smaller than the width of the gap close to the lower base of the trapezoid, which can ensure that most of the light can be received by the outcoupling unit and that the outcoupling unit can project the light to the target position according to the preset trajectory.

[0067] In one embodiment, the present application also provides a method for determining waveguide preparation parameters, see the attached Figure 3 and attached Figure 4 , attached Figure 3 A schematic diagram of a process for determining waveguide preparation parameters in an embodiment of the present application is shown in FIG. Figure 4 A transmission simulation schematic diagram of light r being transmitted through a waveguide to a target position is shown. The method for determining the waveguide preparation parameters in this embodiment can be used to determine the preparation parameters of the waveguide in any of the aforementioned embodiments in this application. The waveguide includes an outcoupling unit having a plurality of outcoupling gratings.

[0068] The method for determining the waveguide preparation parameters in this embodiment includes the following steps S301 to S302.

[0069] Step S301, obtaining a corresponding mathematical model according to the propagation characteristics of the light transmitted through the waveguide to the target position.

[0070] The propagation characteristics of the light transmitted to the target position through the waveguide may be the corresponding relationship between the projection of the light on the plane where the waveguide receives the light and the projection information of the light on the plane where the target position is located. The target position may be the position where the user receives the image information. Figure 4 It shows that the light r projected by the waveguide is transmitted to the windshield 200, and the windshield 200 projects the light to the plane P0 where the target position is located.

[0071] Step S302, determining the number of out-coupling gratings as a target number according to the mathematical model and the size of the preset master mold; the outer contour of the out-coupling grating is a trapezoid.

[0072] The outer contour of the preset master mold is the same as the outer contour of the outcoupling grating, both of which are trapezoidal. According to the mathematical model and the size of the preset master mold, the number of outcoupling gratings is determined as the target number, and the outcoupling unit can be obtained by arranging and designing the outcoupling gratings of the target number. When arranging and designing the outcoupling gratings of the target number, it is necessary to ensure that the fitting error between the geometric center of gravity of the outcoupling grating after arrangement and the target fitting curve is less than 10 -4 mm, the target fitting curve is a quadratic fitting curve of the geometrical centroids of the plurality of trapezoids. The tangent angle corresponding to the difference between the curvature of the quadratic fitting curve of the geometrical centroid of the arranged outcoupling grating and the target curvature is less than 0.3 degrees.

[0073] In this embodiment, a corresponding mathematical model is obtained according to the propagation characteristics of light transmitted through a waveguide to a target position, and the number of out-coupling gratings is determined as a target number based on the mathematical model and the size of a preset master mold. This ensures that the out-coupling unit composed of the target number of out-coupling gratings can meet the requirements for light propagation characteristics and improve the problem of light deflection.

[0074] In one embodiment, the waveguide also includes a coupling unit; obtaining a corresponding mathematical model based on the propagation characteristics of the light transmitted through the waveguide to the target position includes: obtaining first light information of the light in the plane where the coupling unit is located; obtaining second light information of the light in the plane where the target position is located; and obtaining a mathematical model based on the first light information and the second light information.

[0075] For example, the propagation characteristics of light transmitted through a waveguide to a target position may be recorded by a Polynomial function to obtain a corresponding mathematical model.

[0076] See attached Figure 5 , attached Figure 5 A schematic diagram of a light distribution simulation on the plane P1 where the coupling unit 120 is located is shown. The first light information may refer to the projection point information of the light on the plane P1 where the coupling unit 120 is located.

[0077] The second light information may refer to the projection point information of the plane where the target position of the light is located, for example, it may be the projection point information of the light on the user's field of view.

[0078] In this embodiment, a mathematical model is obtained based on the first light information and the second light information. The mathematical model can accurately characterize the propagation characteristics of the light. The preparation parameters of the waveguide are obtained based on the mathematical model, so that the waveguide prepared based on the preparation parameters can accurately transmit the light to the target position in the application scenario, thereby improving the light deflection.

[0079] In one embodiment, the mathematical model is:

[0080] U=A(1)+A(2)X+A(3)Y+A(4)XY+A(5)X 2 +A(6)Y 2 ;

[0081] V=B(1)+B(2)X+B(3)Y+B(4)XY+B(5)X 2 +B(6)Y 2 ;

[0082] Wherein, U and V are the first light information of the light in the plane where the coupling-in unit is located; X and Y are the second light information of the light coupled out by the coupling-out unit in the plane where the target position is located; A(1) is a preset basic displacement item corresponding to the position information in the U direction in the first light information; A(2) and A(3) are preset slope items corresponding to the position information in the U direction in the first light information; A(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the U direction in the first light information; A(5) and A(6) are preset slope change items corresponding to the position information in the U direction in the first light information; B(1) is a preset basic displacement item corresponding to the position information in the V direction in the first light information; B(2) and B(3) are preset slope items corresponding to the position information in the V direction in the first light information; B(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the V direction in the first light information; B(5) and B(6) are preset slope change items corresponding to the position information in the V direction in the first light information.

[0083] Wherein, the value of A(1) can be adjusted according to the target size and setting position of the waveguide. The value of A(2) is between 0.8 and 0.97, for example, it can be 0.8, 0.82, 0.85, 0.88, 0.90, 0.92, 0.95, 0.97, etc., but not limited to this. The value of A(3) is between 0.25 and 0.5, for example, it can be 0.25, 0.28, 0.30, 0.32, 0.35, 0.38, 0.41, 0.44, 0.46, 0.48, 0.5, etc., but not limited to this. The value of B(2) is between 0.25 and 0.5, for example, it can be 0.25, 0.28, 0.30, 0.32, 0.35, 0.38, 0.41, 0.44, 0.46, 0.48, 0.5, etc., but not limited to this. The value of B(3) is between 0.8 and 0.97, for example, it can be 0.8, 0.82, 0.85, 0.88, 0.90, 0.92, 0.95, 0.97, etc., but not limited to this. The values ​​of A(4) and B(4) are less than 0.3, for example, they can be 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.29, etc., but not limited to this. The value of A(5) is between 0 and 0.5, for example, it can be 0, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.30, 0.32, 0.35, 0.38, 0.41, 0.44, 0.46, 0.48, 0.5, etc., but not limited to this. The value of A(6) is between 0 and 0.2, for example, it can be 0, 0.1, 0.12, 0.15, 0.18, 0.2, etc., but not limited to this. The value of B(5) is between 0 and 0.2, for example, it can be 0, 0.1, 0.12, 0.15, 0.18, 0.2, etc., but not limited to this. The value of B(6) is between 0 and 0.5, for example, it can be 0, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.30, 0.32, 0.35, 0.38, 0.41, 0.44, 0.46, 0.48, 0.5, etc., but not limited to this.

[0084] In one embodiment, the target number includes the number of out-coupling gratings in the first direction and the number of out-coupling gratings in the second direction; the second direction is perpendicular to the second direction; and the formula for determining the number of out-coupling gratings as the target number according to the mathematical model and the size of the preset master mold is:

[0085] D1=floor(2*(B(5)+B(6))*W / h);

[0086] D2=floor(2*(A(5)+A(6))*W / h);

[0087] Wherein, D1 is the number of out-coupling gratings in the first direction; D2 is the number of out-coupling gratings in the second direction; W is the target size of the out-coupling unit in the first direction; h is the target size of the out-coupling unit in the second direction and the size of the preset master mold in the second direction; floor is an unconditional carry operation function symbol.

[0088] In this embodiment, the size of the outcoupling unit in the second direction may be 1, that is, D2 may be 1.

[0089] In this embodiment, the number of outcoupling gratings in the first direction and the second direction is determined according to the mathematical model and the size of the preset master mold, which can improve the uniformity of the light output brightness of the outcoupling unit and ensure the display quality.

[0090] In one embodiment, see the attached Figure 6 , attached Figure 6 A schematic diagram of the structure of a waveguide 100 in an embodiment of the present application is shown, and the waveguide 100 in this embodiment also includes a coupling unit 120 and a spreading unit 130; the method for determining the waveguide preparation parameters also includes: obtaining the relative position parameters between the coupling unit 110, the spreading unit 130 and the coupling unit 120 according to the prepared coupling unit 110, so that the coupling unit 120 can access the light at a target angle and transmit the light to the spreading unit 130, and the spreading unit 130 projects the accessed light to the target position in at least part of the coupling grating 111.

[0091] Exemplarily, the coupling unit 120 receives light, the spreading unit 130 is used to adjust the distribution of the electromagnetic field in the waveguide 100, and the coupling unit 110 projects the light transmitted by the spreading unit 130 to the windshield. After the coupling unit 110 is prepared, the coupling unit 120 and the spreading unit 130 are first randomly set, and ray tracing is performed based on the propagation of light in the coupling unit 120, the spreading unit 130 and the coupling unit 110. According to the ray tracing results, the relative position parameters between the coupling unit 110, the spreading unit 130 and the coupling unit 120 are adaptively adjusted, so that the coupling unit 120 receives the light at a target angle and transmits the light to the spreading unit 130, and the spreading unit 130 projects the received light to the target position in at least part of the coupling grating 111, ensuring that the light is propagated as required.

[0092] In one embodiment, the present application further provides a waveguide preparation method, and the waveguide prepared by the waveguide preparation method can be the waveguide in any of the aforementioned embodiments of the present application. The waveguide includes an outcoupling unit, and the outcoupling unit includes a plurality of outcoupling gratings 111 .

[0093] The waveguide preparation method in this embodiment includes: reprinting a preset master mold 1111 according to the preparation parameters determined by the method for determining waveguide preparation parameters in any of the aforementioned embodiments of the present application to obtain a coupling master mold 1112 containing a target number of coupling gratings 111; and preparing a waveguide based on the coupling master mold 1112.

[0094] For example, taking the target number as 3, see the attached Figure 7 , attached Figure 7 A schematic diagram of a process of reprinting a preset master mold 1111 in an embodiment of the present application to obtain a coupling master mold 1112 containing a target number of coupling gratings 111. In this embodiment, compared with a complete coupling unit, the size of the preset master mold 1111 is much smaller than that of the coupling unit, and reprinting the preset master mold 1111 to obtain a coupling master mold 1112 containing a target number of coupling gratings 111 can simplify the difficulty of stamping and demolding, reduce the difficulty of manufacturing the coupling master mold 1112, and improve the demolding success rate and production efficiency.

[0095] In one embodiment, see the attached Figures 8-9 , attached Figure 8 FIG. 1 shows one of the flow diagrams of preparing a waveguide 100 based on a coupled-out mother mold in an embodiment of the present application, and FIG. Fig. 9 The second schematic diagram of the process of preparing the waveguide 100 based on the decoupling master mold in one embodiment of the present application is shown. In this embodiment, the process of preparing the waveguide 100 based on the decoupling master mold includes the following steps S801 to S804.

[0096] Step S801, obtaining a waveguide master mold 901 based on the decoupled master mold.

[0097] Step S802 , performing panel expansion on the waveguide master mold 901 to obtain a waveguide panel 902 .

[0098] For example, a 12-inch wafer glass can be exposed and developed by a spin coater, so as to obtain a waveguide master mold 901 based on the coupled master mold. After the accuracy of the slit coater is measured and calibrated, the waveguide master mold 901 can be spliced ​​and expanded by the slit coater and the splicing machine. A waveguide splicing 902 can include multiple waveguide master molds 901. For example, Figure 8 The example shows a waveguide panel 902 including three waveguide master molds 901 .

[0099] Step S803 , transferring the waveguide plate 902 to obtain a plurality of working molds 904 .

[0100] For example, the waveguide imposition plate 902 may be transferred once to obtain the replica mold 903, and then the replica mold 903 may be transferred twice to obtain the working mold 904. The waveguide imposition plate 902 may be transferred once to achieve at least 100 times for each waveguide imposition plate 902, and the replica mold 903 may be transferred twice to achieve at least 100 times for each replica mold 903, thereby reducing the preparation cost.

[0101] Step S804 , cutting and assembling the plurality of working molds 904 to obtain the waveguide 100 .

[0102] After each preparation process, a random inspection may be performed to ensure the preparation quality of the preparation process. After executing step S804, the waveguide 100 may be optically inspected to further ensure the quality of the finally prepared waveguide 100.

[0103] In this embodiment, the waveguide 100 is prepared through steps S801 to S804, which can improve production efficiency. In the waveguide 100 prepared in the embodiment of the present application, the outer contour of the outcoupling grating is a trapezoid, and multiple outcoupling gratings form an outcoupling unit, which means that the outcoupling unit can form an ideal parabolic light reflection structure, can focus parallel light rays to one point, has a stronger line focusing ability, can improve the light deflection problem, thereby reducing aberrations and improving imaging quality. And light deflection can be avoided without adding an additional phase compensation plate or setting an additional phase compensation mechanism, which reduces the preparation cost.

[0104] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0105] In one embodiment, the present application further provides a head-up display device, comprising a waveguide as in any of the foregoing embodiments of the present application; or, comprising a waveguide as in any of the foregoing embodiments of the present application.

[0106] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0107] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the application. It should be noted that, for a person of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A waveguide, characterized in that: The waveguide comprises an outcoupling unit; the outcoupling unit comprises a plurality of outcoupling gratings, and the outer contour of the outcoupling gratings is a trapezoid; The outcoupling grating comprises a periodically arranged linear structure, wherein the extension direction of the linear structure is parallel to the extension direction of the bottom side of the trapezoid, and the arrangement direction of the linear structure is perpendicular to the extension direction of the bottom side of the trapezoid; The fitting error between the geometric center of gravity of the multiple trapezoids and the target fitting curve is less than 10 -4 mm, the target fitting curve is a quadratic fitting curve of the geometric centroids of the multiple trapezoids, the upper bases of the multiple trapezoids are located on the same side of the quadratic fitting curve, and the upper base is the longer of the two bases of the trapezoid.

2. The waveguide according to claim 1, characterized in that The tangent angle corresponding to the difference between the curvature of the quadratic fitting curve and the target curvature is less than 0.3 degrees.

3. The waveguide according to claim 1, characterized in that A gap with a gradually changing width is provided between at least two adjacent outcoupling gratings.

4. The waveguide according to claim 3, characterized in that The width of the gap on a side close to the upper base of the trapezoid is smaller than the width of the gap on a side close to the lower base of the trapezoid.

5. A method for determining waveguide preparation parameters, characterized in that: Used to determine the preparation parameters of the waveguide according to any one of claims 1 to 4; the waveguide includes a coupling unit provided with a plurality of coupling gratings; the method for determining the waveguide preparation parameters includes: Acquire a corresponding mathematical model according to the propagation characteristics of the light transmitted through the waveguide to the target position; The number of the out-coupling gratings is determined as a target number according to the mathematical model and the size of the preset master mold; and the outer contour of the out-coupling grating is a trapezoid.

6. The method for determining waveguide preparation parameters according to claim 5, characterized in that: The waveguide further includes a coupling unit; the corresponding mathematical model is obtained according to the propagation characteristics of the light transmitted through the waveguide to the target position, including: Acquire first light information of the light on the plane where the coupling unit is located; Obtaining second light information on the plane where the light is located at the target position; The mathematical model is acquired according to the first light information and the second light information.

7. The method for determining waveguide preparation parameters according to claim 6, characterized in that: The mathematical model is: U=A(1)+A(2)X+A(3)Y+A(4)XY+A(5)X 2 +A(6)Y 2 ; V=B(1)+B(2)X+B(3)Y+B(4)XY+B(5)X 2 +B(6)Y 2 ; Wherein, U and V are the first light information of the light in the plane where the coupling-in unit is located; X and Y are the second light information of the light coupled out by the coupling-out unit in the plane where the target position is located; A(1) is a preset basic displacement item corresponding to the position information in the U direction in the first light information; A(2) and A(3) are preset slope items corresponding to the position information in the U direction in the first light information; A(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the U direction in the first light information; A(5) and A(6) are preset slope change items corresponding to the position information in the U direction in the first light information; B(1) is a preset basic displacement item corresponding to the position information in the V direction in the first light information; B(2) and B(3) are preset slope items corresponding to the position information in the V direction in the first light information; B(4) is a preset spatial coordinate dependence coefficient corresponding to the position information in the V direction in the first light information; B(5) and B(6) are preset slope change items corresponding to the position information in the V direction in the first light information.

8. The method for determining waveguide preparation parameters according to claim 7, characterized in that: The target number includes the number of the out-coupling gratings in the first direction and the number of the out-coupling gratings in the second direction; the second direction is perpendicular to the second direction; the formula for determining the number of the out-coupling gratings as the target number according to the mathematical model and the size of the preset master mold is: D1=floor(2*(B(5)+B(6))*W / h); D2=floor(2*(A(5)+A(6))*W / h); Wherein, D1 is the number of the outcoupling gratings in the first direction; D2 is the number of the outcoupling gratings in the second direction; W is the target size of the outcoupling unit in the first direction; h is the target size of the outcoupling unit in the second direction and the size of the preset master mold in the second direction; floor is an unconditional carry operation function symbol.

9. The method for determining waveguide preparation parameters according to claim 5, characterized in that: The waveguide further includes a coupling unit and a spreading unit; the method for determining the waveguide preparation parameters further includes: The relative position parameters between the out-coupling unit, the spreading unit and the coupling-in unit are obtained according to the prepared out-coupling unit, so that the coupling-in unit receives the light at a target angle and transmits the light to the spreading unit, and the spreading unit projects the received light to the target position in at least part of the out-coupling grating.

10. A waveguide preparation method, characterized in that: The waveguide is a waveguide as claimed in any one of claims 1 to 4; the waveguide comprises an outcoupling unit, and the outcoupling unit comprises a plurality of outcoupling gratings; the waveguide preparation method comprises: Reprinting a preset master mold according to the preparation parameters determined by the method for determining waveguide preparation parameters according to any one of claims 5 to 9 to obtain a coupling-out master mold containing a target number of the coupling-out gratings; The waveguide is prepared based on the decoupled master mold.

11. The waveguide preparation method according to claim 10, characterized in that: The step of preparing the waveguide based on the out-coupling master mold comprises: Acquire a waveguide master mold based on the outcoupled master mold; Performing plate-building and mold-expanding on the waveguide master mold to obtain a waveguide plate-building; Transfer printing the waveguide imposition plate to obtain a plurality of working molds; A plurality of the working molds are cut and assembled to obtain the waveguide.

12. A head-up display device, characterized in that: comprising a waveguide as claimed in any one of claims 1 to 4; or, Comprising a waveguide as claimed in any one of claims 5 to 10.

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