Optical waveguides, their fabrication methods, devices, and vehicles

Abstract

This application provides an optical waveguide and its fabrication method, apparatus, and vehicle, comprising: a transparent substrate; a patterned layer disposed on one side of the transparent substrate and bonded to the transparent substrate; and a thickening substrate disposed on the side of the transparent substrate away from the patterned layer and bonded to the transparent substrate by a transparent optical adhesive, so that the overall thickness of the optical waveguide is greater than 5 mm. This application controls the thickness of the transparent substrate by setting a patterned layer on one side of the transparent substrate, enabling smooth fabrication of the optical waveguide. After the optical waveguide grating pattern is fabricated, i.e., after the patterned layer is fabricated on the transparent substrate, a thickening substrate used to increase the overall thickness is bonded to the other side of the transparent substrate using transparent optical adhesive, thereby forming an optical waveguide with a thickness meeting specific requirements. Ultimately, this increases the light transmission step length in the waveguide, reduces light loss, and improves luminous efficiency.

Description

Technical Field

[0001] This application relates to the field of surface imaging technology, and in particular to an optical waveguide and its fabrication method, apparatus and vehicle. Background Technology

[0002] In the current field of intelligent vehicle assistance, head-up displays (HUDs), also known as head-up display systems, project important driving information such as speed and navigation onto the windshield in front of the driver, allowing the driver to see it without looking down or turning their head. Currently, AR-HUD (Augmented Reality HUD) technology is increasingly becoming a focus of market attention.

[0003] AR-HUD technology is mainly based on optical waveguide technology. However, in current optical waveguide products, due to the limitations of imprinting equipment, the transparent substrate used for imprinting cannot be too thick, resulting in thin optical waveguide products. Consequently, the light transmission step size in the waveguide is too small, requiring multiple reflections, which leads to significant light loss and low light efficiency. Summary of the Invention

[0004] In view of this, this application proposes an optical waveguide and its fabrication method, apparatus and vehicle, thereby increasing the thickness of the optical waveguide, increasing the light propagation step length in the waveguide, reducing light loss and improving optical efficiency.

[0005] For the purposes described above, this application provides an optical waveguide, comprising:

[0006] Transparent substrate;

[0007] A patterned layer is disposed on one side of the transparent substrate and is adhered to the transparent substrate;

[0008] A thickened substrate is disposed on the side of the transparent substrate away from the pattern layer and bonded to the transparent substrate with transparent optical adhesive, so that the overall thickness of the optical waveguide is greater than 5 mm.

[0009] In some embodiments, the pattern layer includes: an input grating and an output grating, the input grating and the output grating being disposed on the side of the pattern layer away from the transparent substrate; the input grating and the output grating are spaced apart by a certain distance.

[0010] In some embodiments, the thickness of the thickened substrate ranges from 1 mm to 10 mm.

[0011] Based on the same concept, this application also provides a method for fabricating an optical waveguide as described in any of the preceding claims, comprising:

[0012] A transfer film is obtained, wherein an imprinted pattern corresponding to the pattern layer is provided on the transfer film;

[0013] An imprinting adhesive is coated on one side of a transparent substrate, and the transfer film is then covered with the imprinting adhesive to imprint a pattern, thereby generating the pattern layer on the transparent substrate.

[0014] A transparent optical adhesive is applied to the side of the transparent substrate away from the pattern layer. The transparent substrate is then moved to a thickened substrate that matches the transparent substrate, so that the transparent substrate and the thickened substrate are bonded together by the transparent optical adhesive.

[0015] In some embodiments, the transfer film further includes: a film body; the process of obtaining the transfer film includes:

[0016] At least one pattern template is fixed, template adhesive is applied to the pattern surface of the pattern template, and the soft film body is covered with the template adhesive;

[0017] The soft film body is pressed, and the template adhesive is cured to fix the pattern on the pattern template to the template adhesive, and the template adhesive is fixed to the soft film body to obtain the transfer soft film with the embossed pattern.

[0018] In some embodiments, before fixing at least one pattern template, the method further includes:

[0019] At least one side of a substrate silicon wafer is coated with electron beam resist; the substrate silicon wafer coated with electron beam resist is subjected to pattern exposure to generate a corresponding pattern on the electron beam resist;

[0020] The substrate silicon wafer is etched using the electron beam resist that forms a pattern after exposure;

[0021] After etching, the electron beam adhesive on the substrate silicon wafer is peeled off to obtain at least one of the pattern templates.

[0022] In some embodiments, fixing at least one pattern template includes:

[0023] The pattern template is placed on a fixed substrate; wherein, the fixed substrate is provided with a fixing fixture of the same height as the pattern template, and the fixing fixture is provided with a through hole corresponding to the pattern template; the pattern template is accommodated through the through hole of the fixing fixture to fix the pattern template.

[0024] In some embodiments, when there are at least two pattern templates, fixing at least one pattern template includes:

[0025] The pattern template is assembled according to a preset graphic, and the assembled pattern template is placed into the through hole of the fixing fixture to fix the assembled pattern template.

[0026] In some embodiments, before splicing the pattern template according to the preset graphic, the method further includes:

[0027] The pattern template is cut according to the required shape according to the preset splicing rules to form the pattern template of the preset shape.

[0028] In some embodiments, moving the transparent substrate onto a thickened substrate that matches the transparent substrate includes:

[0029] A sealing adhesive protruding from the pattern layer is provided around the periphery of the pattern layer on the transparent substrate;

[0030] The protruding portion of the sealing adhesive is used to bond with the transfer substrate, so that the transparent substrate can be moved by the transfer substrate;

[0031] The transparent substrate is moved onto the thickened substrate via the transfer substrate.

[0032] In some embodiments, after bonding the transparent substrate to the thickened substrate using the transparent optical adhesive, the method further includes:

[0033] Dissolve the sealing adhesive to make it flush with the pattern layer or to completely dissociate the sealing adhesive.

[0034] Remove the transfer substrate.

[0035] In some embodiments, moving the transparent substrate onto a thickened substrate that matches the transparent substrate includes:

[0036] Photoresist is coated on the patterned layer of the transparent substrate and cured to move the transparent substrate.

[0037] The transparent substrate is moved onto the thickened substrate using the cured photoresist.

[0038] In some embodiments, after bonding the transparent substrate to the thickened substrate using the transparent optical adhesive, the method further includes:

[0039] The photoresist is dissolved and removed.

[0040] Based on the same concept, this application also provides an apparatus for fabricating an optical waveguide, comprising:

[0041] The acquisition module is used to acquire the transfer soft film, on which an imprinted pattern corresponding to the pattern layer is provided;

[0042] A generation module is used to coat an imprinting adhesive on one side of a transparent substrate, cover the transfer soft film with the imprinting adhesive to imprint a pattern, so as to generate the pattern layer on the transparent substrate;

[0043] A thickening module is used to apply transparent optical adhesive to the side of the transparent substrate away from the pattern layer, and to move the transparent substrate to a thickening substrate that matches the transparent substrate, so as to bond the transparent substrate and the thickening substrate together by means of the transparent optical adhesive.

[0044] Based on the same concept, this application also provides a vehicle, including: an optical waveguide as described in any of the preceding claims.

[0045] As can be seen from the above description, this application provides an optical waveguide and its fabrication method, apparatus, and vehicle, comprising: a transparent substrate; a patterned layer disposed on one side of the transparent substrate and bonded to the transparent substrate; and a thickening substrate disposed on the side of the transparent substrate away from the patterned layer and bonded to the transparent substrate by a transparent optical adhesive, so that the overall thickness of the optical waveguide is greater than 5 mm. This application controls the thickness of the transparent substrate by setting a patterned layer on one side of the transparent substrate, enabling the smooth fabrication of the optical waveguide. After the optical waveguide grating pattern is fabricated, i.e., after the patterned layer is fabricated on the transparent substrate, a thickening substrate used to increase the overall thickness is bonded to the other side of the transparent substrate using transparent optical adhesive, thereby forming an optical waveguide with a thickness meeting specific requirements. Ultimately, this increases the light transmission step length in the waveguide, reduces light loss, and improves light efficiency. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A schematic diagram of the cross-sectional structure of an optical waveguide provided in an embodiment of this application;

[0048] Figure 2 A schematic diagram of a planar structure of a patterned layer in an optical waveguide, provided in an embodiment of this application;

[0049] Figure 3 This is a schematic diagram illustrating the effect of an optical waveguide applied to HUD imaging, as provided in an embodiment of this application.

[0050] Figure 4 A schematic flowchart illustrating a method for fabricating an optical waveguide according to an embodiment of this application;

[0051] Figure 5 A schematic diagram of the embossing structure when embossing a pattern layer as provided in the embodiments of this application;

[0052] Figure 6 A schematic diagram of the imprinting structure when imprinting a pattern onto a soft film provided in an embodiment of this application;

[0053] Figure 7a This is a schematic diagram of the structure of a silicon substrate wafer coated with electron beam adhesive according to an embodiment of this application;

[0054] Figure 7b This is a schematic diagram of the structure during electron beam photoresist exposure provided in an embodiment of this application;

[0055] Figure 7c This is a schematic diagram of the etched substrate silicon wafer provided in an embodiment of this application;

[0056] Figure 7d This is a schematic diagram of the arrangement of pattern templates on a fixed substrate according to an embodiment of this application;

[0057] Figure 8 This is a schematic diagram of a structure for moving a transparent substrate according to an embodiment of this application;

[0058] Figure 9 This is a schematic diagram of another movable transparent substrate provided in an embodiment of this application;

[0059] Figure 10 This is a schematic diagram of the fabrication apparatus for an optical waveguide provided in an embodiment of this application. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this specification clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0061] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element, object, or method step preceding the term covers the element, object, or method step listed after the term and its equivalents, without excluding other elements, objects, or method steps. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0062] As described in the background section, with the rapid development of 5G, cloud computing, and intelligent driving in recent years, automotive central control screens and instruments provide increasingly more information, causing drivers to frequently look down to check information while driving, posing serious safety hazards. This has led to the emergence of HUD technology. Currently, HUDs can be divided into three types: C-HUD (Combiner HUD), W-HUD (Windshield HUD), and AR-HUD. The first two types of HUD technology have extremely limited information capacity and cannot meet the ever-increasing demand for information prompts, making AR-HUD increasingly the focus of market attention. However, in order to achieve a larger field of view (FOV) and a greater virtual image distance (VID), the size of AR-HUD systems based on freeform surfaces increases rapidly with the optimization of these parameters, even exceeding the space available for the instrument panel. Therefore, to reduce the size of AR-HUD systems, there is increasing attention in this field on AR-HUDs based on optical waveguide technology.

[0063] There are three technical approaches to optical waveguides: geometric waveguides, volume holographic grating waveguides, and surface relief grating waveguides. Geometric waveguides are complex to manufacture, prone to interference from splicing boundaries, and require heavy composite mirrors. Volume holographic gratings, on the other hand, typically use dichromates, which are explosive and hazardous chemicals, causing environmental pollution. Surface relief gratings, with their manufacturing process compatible with semiconductor processes and capable of mass production when combined with nanoimprint lithography equipment, are currently a promising optical waveguide technology. However, the current bottleneck for surface relief grating waveguides lies in the limitations on the thickness of the material (such as glass) used in large-scale nanoimprint lithography equipment for displays during the grating process. The generally applicable thickness range is 0.3mm to 3mm; thicker materials cannot be transferred to the imprinting chamber by the robotic arm and may damage the rollers of the imprinting equipment. However, if the substrate thickness of the optical waveguide is insufficient (e.g., less than 5 mm), the light propagation step size in the waveguide will be too small, resulting in high energy loss in the coupling region due to excessive reflections, thus reducing the optical efficiency.

[0064] In light of the above-mentioned practical situation, this application proposes an optical waveguide solution. This application sets a pattern layer on one side of a transparent substrate to control the thickness of the transparent substrate itself, enabling the smooth fabrication of the optical waveguide. After the optical waveguide grating pattern is fabricated, i.e., after the pattern layer is fabricated on the transparent substrate, a thickened substrate used to increase the overall thickness is bonded to the other side of the transparent substrate using transparent optical adhesive, thereby forming an optical waveguide with a thickness that meets specific requirements. Ultimately, this increases the light transmission step length in the waveguide, reduces light loss, and improves light efficiency.

[0065] like Figure 1 The diagram shown is a schematic representation of an optical waveguide according to an embodiment of this application. Specifically, the optical waveguide of this embodiment includes:

[0066] Transparent substrate 110;

[0067] A pattern layer 120 is disposed on one side of the transparent substrate 110 and is bonded to the transparent substrate 110;

[0068] A thickened substrate 130 is disposed on the side of the transparent substrate 110 away from the pattern layer 120 and is bonded to the transparent substrate 110 by a transparent optical adhesive 140, so that the overall thickness of the optical waveguide is greater than 5mm.

[0069] In this embodiment, the transparent substrate 110, the thickened substrate 130, and the transparent optical adhesive 140, being components of the optical waveguide structure, are generally made of transparent materials and have minimal light restriction. The transparent substrate 110 and the thickened substrate 130 can typically be made of glass, while the transparent optical adhesive 140 can be OCA optical adhesive. OCA (Optically Clear Adhesive) is a special adhesive used to bond transparent optical components (such as lenses). It is required to be colorless and transparent, with a light transmittance of over 95%, good bonding strength, curing at room temperature or medium temperature, and low curing shrinkage. The pattern layer 120 then forms the grating portion of the optical waveguide used to refract light; it is a typical patterned area of ​​an optical waveguide and may include input and output gratings, etc.

[0070] In this embodiment, since the optical waveguide is divided into two parts by the transparent optical adhesive 140, during the imprinting process of the pattern layer 120, only the transparent substrate 110 needs to be placed in the imprinting equipment. Furthermore, the thickness of the transparent substrate 110 can be arbitrarily adjusted according to the requirements of the imprinting equipment, enabling the successful imprinting of the pattern layer 120. Subsequently, to meet the thickness requirements of optical waveguides in specific applications such as automotive, a thickening substrate 130 can be added to the side of the transparent substrate 110 away from the pattern layer 120 using the transparent optical adhesive 140. This thickening substrate 130 increases the overall thickness of the optical waveguide, ensuring that the final optical waveguide meets the requirements of various AR-HUD systems, satisfying various FOV and VID requirements. Generally, in current market demands, the overall thickness of the optical waveguide needs to be increased to greater than 5mm to meet the specific FOV and VID requirements of current AR-HUD systems. Simultaneously, the size of the thickening substrate 130 is generally comparable to the size of the transparent substrate 110.

[0071] In an optional embodiment, such as Figure 1 and Figure 2 As shown, the pattern layer 120 includes: an input grating 121 and an output grating 122, the input grating 121 and the output grating 122 being disposed on the side of the pattern layer 120 away from the transparent substrate 110; the input grating 121 and the output grating 122 are spaced apart by a certain distance.

[0072] In this embodiment, to realize the function of the optical waveguide, the pattern layer 120 generally includes an input grating 121 and an output grating 122. The input grating 121 is used for light introduction. An external light source directs light into the optical waveguide through the input grating 121. After multiple reflections in the optical waveguide, the light exits the optical waveguide through the output grating 122. When setting the input grating 121 and the output grating 122, or during the forming process of the pattern layer 120 (the pattern formed by the pattern layer 120 includes the input grating 121 and the output grating 122), the input grating 121 and the output grating 122 are generally placed on the side of the pattern layer 120 away from the transparent substrate 110. Subsequently, in order to realize the function of the optical waveguide and distinguish between the input grating 121 and the output grating 122, a certain distance can be spaced between the input grating 121 and the output grating 122. The size of the distance can be set according to the specific application scenario. Subsequently, the size and position of the coupling grating 121 generally correspond to the light source, and the size of the coupling grating 122 is generally related to the size of the image. Depending on the specific required image size, the larger the image, the larger the range of the coupling grating 122, and the smaller the image, the smaller the range of the coupling grating 122. The image size here can be understood as the size of the virtual image range seen by the observer (such as the operator of the vehicle system). In some embodiments, the height of each column of the coupling grating 121 and the coupling grating 122 can be set between 10 nm and 400 nm, the width can be set between 20 nm and 800 nm, and the spacing between adjacent gratings (the period of the grating) can be set between 100 nm and 1000 nm. By adjusting the height, width, and period of the gratings, the display parameters such as the clarity, contrast, and screen size of the HUD image can be adjusted. Setting the size of the gratings within the above range can make the image projected by the HUD more in line with the requirements of the vehicle's HUD display. The image projected at this size can provide the operator with clear image guidance without affecting the operator's observation of the external road conditions, thereby improving image quality, image size, and image richness while meeting the safety requirements of the vehicle's HUD. Of course, the above dimensions can be specifically set according to the specific HUD scenario.

[0073] In a specific embodiment, such as Figure 3 The diagram illustrates the effect of applying the optical waveguide of this embodiment to a current in-vehicle head-up display (HUD) system. The waveguide's coupling grating is positioned below the optical engine (for providing a light source) to guide light into the waveguide. The light then undergoes multiple reflections within the waveguide before exiting at the output grating. Both the coupling grating and the output grating are represented within a pattern layer and are part of the pattern on that layer. After exiting the output grating, the light illuminates the windshield of the vehicle's head-up display, and through reflection from the windshield, enters the operator's line of sight, leading the operator to perceive a virtual image formed by the waveguide as being located in front of the head-up display.

[0074] In one optional embodiment, the thickness of the thickened substrate 130 ranges from 1 mm to 10 mm. This is to meet the specific requirements for optical waveguide thickness in different application scenarios.

[0075] As described above, this application provides an optical waveguide comprising: a transparent substrate; a patterned layer disposed on one side of the transparent substrate and bonded to the transparent substrate; and a thickening substrate disposed on the side of the transparent substrate away from the patterned layer and bonded to the transparent substrate by a transparent optical adhesive, so that the overall thickness of the optical waveguide is greater than 5 mm. This application controls the thickness of the transparent substrate by setting a patterned layer on one side of the transparent substrate, enabling the smooth fabrication of the optical waveguide. After the optical waveguide grating pattern is fabricated, i.e., after the patterned layer is fabricated on the transparent substrate, a thickening substrate used to increase the overall thickness is bonded to the other side of the transparent substrate using transparent optical adhesive, thereby forming an optical waveguide with a thickness meeting specific requirements. Ultimately, this increases the light transmission step length in the waveguide, reduces light loss, and improves luminous efficiency.

[0076] Based on the same concept, this application also provides a method for fabricating an optical waveguide as described in any of the above embodiments, such as... Figure 4 As shown, it specifically includes:

[0077] Step 201: Obtain a transfer film, wherein the transfer film has an embossed pattern corresponding to the pattern layer.

[0078] In this embodiment, as Figure 5 , Figure 6 As shown, the transfer soft film 310 is a thin-film structure used to transfer the embossed pattern 311. It generally includes the embossed pattern 311 and a soft film body 312. The pattern can be embossed on the pattern template 320. A template adhesive or similar material can be applied to the pattern template 320, and then the soft film body 312 is covered. Imprinting and curing of the adhesive are then performed, ultimately curing the embossed pattern 311 on the soft film body 312. In a specific embodiment, the embossed pattern 311 has the opposite texture to the final pattern generated on the pattern layer 120. That is, the protruding parts of the embossed pattern 311 become recessed parts after being imprinted onto the pattern layer 120. Therefore, in some embodiments, the embossed pattern 311 is also referred to as the inverse of the pattern on the pattern layer 120. Of course, the pattern on the pattern layer 120 is generally consistent with the pattern on the pattern template.

[0079] Step 202: Apply an imprinting adhesive to one side of the transparent substrate, and cover the imprinting adhesive with the transfer film to imprint a pattern, thereby generating the pattern layer on the transparent substrate.

[0080] In this embodiment, as Figure 5 As shown, to form the pattern layer 120, a layer of imprinting adhesive is typically coated on the transparent substrate 110 before imprinting. After the imprinting adhesive cures and the pattern is retained, the pattern layer 120 is formed. The imprinting adhesive can be a common nano-imprinting adhesive used in surface relief grating waveguide processes, such as A2-100 imprinting adhesive. Spin coating can be used to apply the imprinting adhesive. Spin coating (or rotational coating) relies on the centrifugal force and gravity generated when the transparent substrate 110 rotates to evenly distribute the imprinting adhesive droplets falling on the transparent substrate 110 surface. Since the imprinting adhesive itself may have a high density, spin coating can achieve a more uniform thickness of the imprinting adhesive coating. Of course, in some real-time methods, brush coating or other methods can also be used to apply the imprinting adhesive. During spin coating, the rotation speed can range from 100 rpm to 3000 rpm, and the spin coating time can range from 10 s to 120 s.

[0081] After coating, a transfer film 310 bearing the embossing pattern 311 is placed on the embossing adhesive, followed by the embossing process, such as... Figure 5 As shown, rollers and other structures are used to move and press the transfer film 310 back and forth. Simultaneously, the printing adhesive is cured according to its curing requirements, such as by light curing (ultraviolet light, etc.), temperature curing, humidity curing, etc. This ensures that the printing adhesive retains the pattern corresponding to the printed pattern 311, ultimately forming the pattern layer 120.

[0082] Step 203: Apply transparent optical adhesive to the side of the transparent substrate away from the pattern layer, and move the transparent substrate to a thickened substrate that matches the transparent substrate, so as to bond the transparent substrate and the thickened substrate together by the transparent optical adhesive.

[0083] In this embodiment, as Figure 1 As shown, a transparent optical adhesive 140 is disposed on the side of the transparent substrate 110 away from the pattern layer 120. Since the previous imprinting process was performed in an imprinting device, the transparent substrate 110 can be removed from the imprinting device before the transparent optical adhesive 140 is applied. Then, the transparent substrate 110 coated with the transparent optical adhesive 140 is moved onto the thickened substrate 130 for adhesion. Finally, the transparent substrate 110 and the thickened substrate 130 are bonded together by the transparent optical adhesive 140, achieving overall thickening of the optical waveguide. Of course, in some embodiments, the transparent optical adhesive 140 can be applied to either the transparent substrate 110 or the thickened substrate 130.

[0084] The methods described in the above embodiments are applied to the fabrication of the corresponding optical waveguides in the foregoing embodiments. The specific contents of each step and the corresponding beneficial effects have been described in the foregoing embodiments of optical waveguides, so they will not be repeated in this embodiment.

[0085] In an optional embodiment, the transfer film further includes: a film body; obtaining the transfer film includes: fixing at least one pattern template, applying template adhesive to the pattern surface of the pattern template, covering the template adhesive with the film body; pressing the film body, curing the template adhesive to fix the pattern on the pattern template to the template adhesive, and fixing the template adhesive to the film body to obtain the transfer film with the embossed pattern.

[0086] In this embodiment, as Figure 6 As shown, the pattern template 320 is a main film template with a grating pattern engraved on it. During the fabrication of the optical waveguide, the pattern on the pattern template 320 needs to be imprinted using the flexible film body 312 and a layer of template adhesive (which forms an imprinted pattern 311 after imprinting and curing) coated on the flexible film body 312 or the pattern template 320, so that the pattern (or the inverse of the pattern) is retained on the imprinted pattern 311. Then, the pattern is transferred to the transparent substrate 110 and the template adhesive on it using the imprinted pattern 311 on the flexible film body 312. During the imprinting process, the pattern template 320 is first fixed to prevent it from shifting and causing the imprinted pattern to deviate. Then, a layer of template adhesive can be coated on the pattern template 320, and the flexible film body 312 can be covered on the template adhesive. The imprinting is performed using a roller, and the adhesive is cured using a curing method corresponding to the template adhesive, such as light curing (ultraviolet light, etc.), temperature curing, humidity curing, etc. A patterned template adhesive is cured onto the flexible film body 312 to form an imprinted pattern 311 on the flexible film body 312, thereby forming a transfer flexible film 310. The flexible film body 312 is a flexible thin-film structure with a certain degree of toughness. The template adhesive is similar to the imprinting adhesive and can be a general template adhesive used in surface relief grating waveguide processes, such as AS2 template adhesive. The template adhesive can be applied using a spin coating process, with a spin coating speed range of 500rpm-6000rpm and a spin coating time of 10s-120s.

[0087] In an optional embodiment, before fixing at least one pattern template, the method further includes: coating one side of at least one substrate silicon wafer with electron beam resist; patterning the substrate silicon wafer coated with the electron beam resist to generate a corresponding pattern on the electron beam resist; etching the substrate silicon wafer with the pattern formed by the electron beam resist after exposure; and after etching, peeling off the electron beam resist on the substrate silicon wafer to obtain at least one pattern template.

[0088] In this embodiment, as Figures 7a to 7c As shown, to create the pattern template 320, at least one substrate silicon wafer 321 is first required. The size of the substrate silicon wafer 321 can be from 3 inches to 12 inches. Then, an electron beam resist 322 is coated on it. After that, the photoresist is patterned by exposure and development using an electron beam (EB). The substrate silicon wafer is then etched according to the current pattern of the electron beam resist 322. After etching is completed, the electron beam resist 322 is peeled off, resulting in the etched substrate silicon wafer 321. Figure 7c This refers to the pattern template 320. In some specific applications, the substrate silicon wafer 321 can also be replaced with glass. In this embodiment, the substrate silicon wafer 321 is usually a circular thin-film structure, but it can also be a polygonal structure, such as a triangle, rectangle, trapezoid, parallelogram, hexagon, or other polygons. The substrate silicon wafer 321 itself can be one of these polygonal structures, or it can be a substrate silicon wafer 321 cut into the corresponding shape.

[0089] In an optional embodiment, fixing at least one pattern template includes: placing the pattern template on a fixing substrate; wherein the fixing substrate is provided with a fixing fixture of the same height as the pattern template, and the fixing fixture is provided with a through hole corresponding to the pattern template; the pattern template is accommodated through the through hole of the fixing fixture to fix the pattern template.

[0090] In this embodiment, as Figure 6 and Figure 7d As shown, to fix the pattern template 320, it can be placed on a fixing substrate 330. The fixing substrate 330 can be made of glass or other materials, and its thickness is not specifically required. Then, to fix the position of the pattern template 320 on the plane, a fixing fixture 340 can be provided on the fixing substrate 330. The height of the fixing fixture 340 is approximately the same as the height of the pattern template 320, and in specific applications, the error is less than 0.05mm. The fixing fixture 340 has several through holes (determined by the number of pattern templates 320) corresponding to the pattern templates 320. These through holes are used to accommodate the pattern templates 320, thereby fixing them.

[0091] In an optional embodiment, when there are at least two pattern templates, fixing at least one pattern template includes: splicing the pattern templates according to a preset pattern, and placing the spliced ​​pattern template into the through hole of the fixing fixture to fix the spliced ​​pattern template.

[0092] In this embodiment, as Figure 6 and Figure 7d As shown, in the design process of a HUD, in some embodiments, the parameter requirements of the HUD are relatively low (small FOV, close VID), so only one pattern template 320 is needed to generate the optical waveguide pattern to complete the entire HUD implementation. However, in other embodiments, the parameter requirements of the HUD are higher (larger FOV, farther VID), so the pattern of one pattern template 320 cannot meet the requirements of the entire HUD implementation. Therefore, it is necessary to segment the optical waveguide pattern and etch it using different pattern templates 320. After etching each pattern template 320, these pattern templates 320 need to be spliced ​​together according to the original pattern. Then, in the fixing fixture 340, the reserved through holes need to correspond to the pattern templates 320, and so on... Figure 7d As shown, to fix a plurality of pattern templates 320, the spliced ​​pattern templates 320 are placed in a fixing fixture 340. In specific implementations, the splicing seams between the pattern templates 320 are generally at the nanometer to micrometer level. In this embodiment, the pattern templates 320 are derived from a substrate silicon wafer 321. Since the substrate silicon wafer 321 itself can be circular or other shapes, splicing circular substrate silicon wafers 321 will leave a considerable star-shaped gap. Therefore, before splicing, the substrate silicon wafer 321 can be cut. According to a preset pattern design or splicing rules (e.g., splicing rules requiring rectangular or triangular splicing), the circular substrate can be cut into other shapes, such as triangles, rectangles, trapezoids, parallelograms, hexagons, or other polygons, before splicing. That is, before splicing the pattern templates according to the preset pattern, the process also includes: cutting the pattern templates according to the shape required by the preset splicing rules to form the pattern templates of the preset shape.

[0093] In an optional embodiment, moving the transparent substrate onto a thickened substrate that matches the transparent substrate includes: providing a sealing adhesive protruding from the pattern layer around the pattern layer of the transparent substrate; using the protruding portion of the sealing adhesive to adhere to a transfer substrate, so as to move the transparent substrate via the transfer substrate; and moving the transparent substrate onto the thickened substrate via the transfer substrate.

[0094] In this embodiment, as Figure 8 As shown, in order to move the transparent substrate 110 onto the thickened substrate 130, a sealing adhesive 350 can be formed around the pattern layer 120, and the height of the sealing adhesive 350 can be set higher than that of the pattern layer 120. The sealing adhesive 350 is then bonded to the transfer substrate 360, thereby using the transfer substrate 360 ​​to move the transparent substrate 110 onto the corresponding thickened substrate 130 via the sealing adhesive 350.

[0095] In an optional embodiment, after bonding the transparent substrate to the thickened substrate with the transparent optical adhesive, the method further includes: dissolving the sealing adhesive to make the sealing adhesive flush with the pattern layer or to completely detach the sealing adhesive; and removing the transfer substrate.

[0096] In this embodiment, after the bonding of the transparent substrate 110 and the thickened substrate 130 is completed, the sealant 350 and the transfer substrate 360 ​​can be peeled off using means such as laser or heating that can detach the sealant 350. In some embodiments, peeling off the sealant 350 may involve peeling off only the portion of the sealant 350 that extends beyond the pattern layer 120, so that the remaining sealant 350 remains at the same height as the pattern layer 120; alternatively, the sealant 350 may be completely peeled off. Since the sealant 350 itself covers a small area, even if it is completely peeled off, its impact on the optical waveguide itself is very small. Since the main functional areas of the optical waveguide are the coupling grating 121, the coupling grating 122, and the area between them, the transparent substrate 110 extending slightly beyond the pattern layer 120 at the edge will not affect the use of the optical waveguide. At the same time, since the sealant 350 only plays a transfer role, its application range or width is not very large, and the transfer task can be completed with a very small width. Therefore, whether the sealant 350 (even if the sealant 350 is not transparent) is left on the optical waveguide or the transparent substrate 110 extends slightly beyond the pattern layer 120, it will not affect the effect of the optical waveguide. Of course, if the transparent substrate 110 extends too far beyond the pattern layer 120, although it will not affect the coupling grating 121 and the coupling grating 122, the excessively large area will lead to lower space utilization and increased cost. Therefore, the transparent substrate 110 should not extend too far beyond the pattern layer 120.

[0097] In an optional embodiment, moving the transparent substrate onto a thickened substrate that matches the transparent substrate includes: coating a photoresist on the patterned layer of the transparent substrate, curing the photoresist to move the transparent substrate via the photoresist; and moving the transparent substrate onto the thickened substrate via the cured photoresist.

[0098] In this embodiment, as Figure 9 As shown, in order to move the transparent substrate 110 onto the thickened substrate 130, a layer of easily removable photoresist 370 can be coated on the pattern layer 120, and then the photoresist 370 can be cured. The cured photoresist 370 can then be used to move the transparent substrate 110 onto the corresponding thickened substrate 130.

[0099] In an optional embodiment, after bonding the transparent substrate to the thickened substrate with the transparent optical adhesive, the method further includes dissolving and removing the photoresist.

[0100] In this embodiment, after the bonding between the transparent substrate 110 and the thickened substrate 130 is completed, the photoresist 370 can be peeled off and dissolved by means of laser or heating that can dissociate the photoresist 370.

[0101] It should be noted that the method in this application embodiment can be executed by a single device, such as a computer or server. The method in this application embodiment can also be applied in a distributed scenario, where multiple devices cooperate to complete the process. In such a distributed scenario, one of these devices may execute only one or more steps of the method in this application embodiment, and the multiple devices will interact with each other to complete the method described.

[0102] It should be noted that the above description describes specific embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0103] Based on the same concept, corresponding to the methods of any of the above embodiments, this application also provides an apparatus for fabricating an optical waveguide.

[0104] refer to Figure 10 The fabrication apparatus for the optical waveguide includes:

[0105] The acquisition module 410 is used to acquire a transfer soft film, wherein the transfer soft film is provided with an imprinted pattern corresponding to the pattern layer;

[0106] The generation module 420 is used to coat an imprinting adhesive on one side of a transparent substrate, and to cover the imprinting adhesive with the transfer soft film to imprint a pattern, so as to generate the pattern layer on the transparent substrate.

[0107] The thickening module 430 is used to apply transparent optical adhesive to the side of the transparent substrate away from the pattern layer, move the transparent substrate to a thickening substrate that matches the transparent substrate, and bond the transparent substrate to the thickening substrate by the transparent optical adhesive.

[0108] For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing the embodiments of this application, the functions of each module can be implemented in one or more software and / or hardware.

[0109] The apparatus described above is used to implement the corresponding optical waveguide fabrication method in the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0110] In an optional embodiment, the transfer film further includes: a film body; the acquisition module 410 is further configured to:

[0111] At least one pattern template is fixed, template adhesive is applied to the pattern surface of the pattern template, and the soft film body is covered with the template adhesive;

[0112] The soft film body is pressed, and the template adhesive is cured to fix the pattern on the pattern template to the template adhesive, and the template adhesive is fixed to the soft film body to obtain the transfer soft film with the embossed pattern.

[0113] In an optional embodiment, the acquisition module 410 is further configured to:

[0114] At least one side of a substrate silicon wafer is coated with electron beam resist; the substrate silicon wafer coated with electron beam resist is subjected to pattern exposure to generate a corresponding pattern on the electron beam resist;

[0115] The substrate silicon wafer is etched using the electron beam resist that forms a pattern after exposure;

[0116] After etching, the electron beam adhesive on the substrate silicon wafer is peeled off to obtain at least one of the pattern templates.

[0117] In an optional embodiment, the acquisition module 410 is further configured to:

[0118] The pattern template is placed on a fixed substrate; wherein, the fixed substrate is provided with a fixing fixture of the same height as the pattern template, and the fixing fixture is provided with a through hole corresponding to the pattern template; the pattern template is accommodated through the through hole of the fixing fixture to fix the pattern template.

[0119] In an optional embodiment, when there are at least two pattern templates, the acquisition module 410 is further configured to:

[0120] The pattern template is assembled according to a preset graphic, and the assembled pattern template is placed into the through hole of the fixing fixture to fix the assembled pattern template.

[0121] In an optional embodiment, the acquisition module 410 is further configured to:

[0122] The pattern template is cut according to the required shape according to the preset splicing rules to form the pattern template of the preset shape.

[0123] In an optional embodiment, the thickening module 430 is further configured to:

[0124] A sealing adhesive protruding from the pattern layer is provided around the periphery of the pattern layer on the transparent substrate;

[0125] The protruding portion of the sealing adhesive is used to bond with the transfer substrate, so that the transparent substrate can be moved by the transfer substrate;

[0126] The transparent substrate is moved onto the thickened substrate via the transfer substrate.

[0127] In an optional embodiment, the thickening module 430 is further configured to:

[0128] Dissolve the sealing adhesive to make it flush with the pattern layer or to completely dissociate the sealing adhesive.

[0129] Remove the transfer substrate.

[0130] In an optional embodiment, the thickening module 430 is further configured to:

[0131] Photoresist is coated on the patterned layer of the transparent substrate and cured to move the transparent substrate.

[0132] The transparent substrate is moved onto the thickened substrate using the cured photoresist.

[0133] In an optional embodiment, the thickening module 430 is further configured to:

[0134] The photoresist is dissolved and removed.

[0135] Based on the same concept, corresponding to the methods of any of the above embodiments, this application also provides a vehicle, including: an optical waveguide as described in any of the foregoing embodiments.

[0136] The vehicles described above are used to apply the corresponding optical waveguides in the foregoing embodiments, and the beneficial effects of the embodiments with the corresponding optical waveguides will not be repeated here.

[0137] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0138] Additionally, to simplify the description and discussion, and to avoid obscuring the embodiments of this application, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring the embodiments of this application, and this also takes into account the fact that the details of the implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this application will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuits) have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that the embodiments of this application can be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0139] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0140] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. An optical waveguide, characterized in that, include: Transparent substrate; A patterned layer is disposed on one side of the transparent substrate and is adhered to the transparent substrate; A thickened substrate is disposed on the side of the transparent substrate away from the pattern layer and bonded to the transparent substrate with transparent optical adhesive, so that the overall thickness of the optical waveguide is greater than 5 mm. The transparent substrate has a sealing adhesive protruding from the pattern layer around the pattern layer. During the preparation process, the protruding part of the sealing adhesive is used to bond the transparent substrate to the transfer substrate. The transfer substrate moves the transparent substrate to the thickening substrate to bond the transparent substrate to the thickening substrate. When the sealing adhesive is peeled off, only the part that extends beyond the pattern layer is peeled off.

2. The optical waveguide according to claim 1, characterized in that, The pattern layer includes: an input grating and an output grating, wherein the input grating and the output grating are disposed on the side of the pattern layer away from the transparent substrate; the input grating and the output grating are spaced apart by a certain distance.

3. The optical waveguide according to claim 1, characterized in that, The thickness of the thickened substrate ranges from 1 mm to 10 mm.

4. A method for fabricating an optical waveguide as described in any one of claims 1 to 3, characterized in that, include: A transfer film is obtained, wherein an imprinted pattern corresponding to the pattern layer is provided on the transfer film; An imprinting adhesive is coated on one side of a transparent substrate, and the transfer film is then covered with the imprinting adhesive to imprint a pattern, thereby generating the pattern layer on the transparent substrate. A transparent optical adhesive is applied to the side of the transparent substrate away from the pattern layer. The transparent substrate is then moved to a thickened substrate that matches the transparent substrate, so that the transparent substrate and the thickened substrate are bonded together by the transparent optical adhesive.

5. The method according to claim 4, characterized in that, The transfer film further includes: a film body; the process of obtaining the transfer film includes: At least one pattern template is fixed, template adhesive is applied to the pattern surface of the pattern template, and the soft film body is covered with the template adhesive; The soft film body is pressed, and the template adhesive is cured to fix the pattern on the pattern template to the template adhesive, and the template adhesive is fixed to the soft film body to obtain the transfer soft film with the embossed pattern.

6. The method according to claim 5, characterized in that, Before fixing at least one pattern template, the method further includes: At least one side of a substrate silicon wafer is coated with electron beam resist; the substrate silicon wafer coated with electron beam resist is subjected to pattern exposure to generate a corresponding pattern on the electron beam resist; The substrate silicon wafer is etched using the electron beam resist that forms a pattern after exposure; After etching, the electron beam adhesive on the substrate silicon wafer is peeled off to obtain at least one of the pattern templates.

7. The method according to claim 5, characterized in that, The fixing of at least one pattern template includes: The pattern template is placed on a fixed substrate; wherein, the fixed substrate is provided with a fixing fixture of the same height as the pattern template, and the fixing fixture is provided with a through hole corresponding to the pattern template; the pattern template is accommodated through the through hole of the fixing fixture to fix the pattern template.

8. The method according to claim 7, characterized in that, When there are at least two pattern templates, fixing at least one pattern template includes: The pattern template is assembled according to a preset graphic, and the assembled pattern template is placed into the through hole of the fixing fixture to fix the assembled pattern template.

9. The method according to claim 8, characterized in that, Before splicing the pattern template according to the preset graphic, the method further includes: The pattern template is cut according to the required shape according to the preset splicing rules to form the pattern template of the preset shape.

10. The method according to claim 4, characterized in that, Moving the transparent substrate onto a thickened substrate that matches the transparent substrate includes: A sealing adhesive protruding from the pattern layer is provided around the periphery of the pattern layer on the transparent substrate; The protruding portion of the sealing adhesive is used to bond with the transfer substrate, so that the transparent substrate can be moved by the transfer substrate; The transparent substrate is moved onto the thickened substrate via the transfer substrate.

11. The method according to claim 10, characterized in that, After bonding the transparent substrate to the thickened substrate using the transparent optical adhesive, the process further includes: Dissolve the sealing adhesive to make it flush with the pattern layer; Remove the transfer substrate.

12. An apparatus for fabricating an optical waveguide as described in any one of claims 1 to 3, characterized in that, include: The acquisition module is used to acquire the transfer soft film, on which an imprinted pattern corresponding to the pattern layer is provided; A generation module is used to coat an imprinting adhesive on one side of a transparent substrate, cover the transfer soft film with the imprinting adhesive to imprint a pattern, so as to generate the pattern layer on the transparent substrate; A thickening module is used to apply transparent optical adhesive to the side of the transparent substrate away from the pattern layer, and to move the transparent substrate to a thickening substrate that matches the transparent substrate, so as to bond the transparent substrate and the thickening substrate together by means of the transparent optical adhesive.

13. A vehicle, characterized in that, include: The optical waveguide as described in any one of claims 1 to 3.

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