Plastic plate and extrusion forming device thereof, waveguide plate module and augmented reality equipment

Abstract

The invention relates to the field of augmented reality equipment, in particular to a plastic plate and an extrusion forming device thereof, a waveguide plate module and augmented reality equipment. The extrusion forming device for the plastic plate comprises an extrusion mechanism and a roller mechanism, the roller wheel mechanism comprises a first roller wheel and an extrusion part which are arranged in parallel at an interval, the first roller wheel and the extrusion part are used for being matched with each other so that a plastic blank extruded from the extrusion mechanism can be formed into a plastic plate, and a gap between the first roller wheel and the extrusion part is smaller than the thickness of the plastic blank; grooves are formed in the surface of the first roller in the circumferential direction, and the grooves are used for forming supporting protrusions for preventing the plastic plate from sinking due to the fact that part of the plastic plate is suspended in the air. The problem that the plastic plate is sunken in the suspended area can be solved.

Description

Technical Field

[0001] The present application relates to the field of augmented reality devices, and particularly to a plastic sheet, an extrusion forming device thereof, a waveguide sheet module, and an augmented reality device. Background Art

[0002] Plastic sheets are characterized by being lightweight and can replace traditional sheets in many occasions where weight reduction is required. For example, in a waveguide sheet module, a plastic sheet can be used as a protective cover plate to protect the waveguide sheet with a grating structure. At this time, the plastic sheet is generally connected to the waveguide sheet by glue around the perimeter. However, when some areas of the plastic sheet are connected to other components and other areas are suspended, due to the poor stiffness of the plastic sheet, depressions are likely to occur in the suspended areas, affecting the product performance. For example, in a waveguide sheet module, after the plastic sheet is connected to the waveguide sheet by glue around the perimeter, the middle area of the plastic sheet is suspended, and depressions from the periphery to the center are likely to occur, and even Newton's rings and adhesion phenomena occur between the waveguide sheet and the plastic sheet, affecting the user experience. Summary of the Invention

[0003] Based on this, the present application provides a plastic sheet, an extrusion forming device thereof, a waveguide sheet module, and an augmented reality device to solve the problem of depressions occurring in the suspended areas of the plastic sheet.

[0004] The first aspect of the present application provides an extrusion forming device for a plastic sheet, and its technical solution is as follows:

[0005] An extrusion forming device for a plastic sheet includes an extrusion mechanism and a roller mechanism; the roller mechanism includes a first roller and an extrusion member arranged in parallel and at intervals; the first roller and the extrusion member are used to cooperate with each other to form a plastic blank extruded from the extrusion mechanism into a plastic sheet, and the gap between the first roller and the extrusion member is smaller than the thickness of the plastic blank; grooves are arranged on the surface of the first roller along the circumferential direction, and the grooves are used to form support protrusions to prevent the plastic sheet from generating depressions due to some areas being suspended.

[0006] The second aspect of the present application provides a plastic sheet, and its technical solution is as follows:

[0007] A plastic sheet includes a sheet body and support protrusions located on the surface of the sheet body and integrally formed with the sheet body, and the plastic sheet is prepared by the extrusion forming device as described above.

[0008] The third aspect of the present application provides a waveguide sheet module, and its technical solution is as follows:

[0009] A waveguide sheet module, comprising a waveguide sheet, a first plastic sheet and a first connecting member; the waveguide sheet comprises a light-conducting layer and a grating structure located on the surface of the light-conducting layer; the first plastic sheet is as described above; the first plastic sheet comprises a first sheet body and a first supporting protrusion located on the surface of the first sheet body and integrally formed with the first sheet body, the first sheet body is located on the side of the grating structure away from the light-conducting layer, the first supporting protrusion faces the waveguide sheet and abuts against the light-conducting layer or the grating structure; the first connecting member is located between the first plastic sheet and the waveguide sheet to connect the two and surround the grating structure.

[0010] The fourth aspect of the present application provides an augmented reality device, and its technical solution is as follows:

[0011] An augmented reality device, comprising a projection optical machine and the waveguide module as described above;

[0012] The projection optical machine is used to project a light signal, and the light signal includes image information;

[0013] The waveguide module is used to transmit the optical signal.

[0014] This application has the following beneficial effects:

[0015] The extrusion molding device of the present application includes an extrusion mechanism and a roller mechanism. The extrusion mechanism can extrude a plastic blank, and the extruded plastic blank can be formed into a plastic plate under the extrusion of the roller mechanism. Among them, the surface of the first roller in the roller mechanism is provided with grooves along the circumferential direction. When the relatively thick plastic blank enters the gap between the first roller and the extrusion member with a relatively small gap, it is extruded by the first roller and the extrusion member, and a part of the plastic blank enters the groove of the first roller. After molding, a plastic plate with a supporting protrusion can be obtained. The formed supporting protrusion can prevent the occurrence of depressions due to the suspension of part of the plastic plate, thereby avoiding the influence of the depression on the product performance. The plastic plate prepared by the extrusion molding device of the present application can be used as a protective cover in fields such as waveguide modules to avoid the generation of Newton rings and adhesion between the waveguide and the plastic plate, and provide a good user experience. At the same time, the cost of preparing the plastic sheet by the extrusion molding device of the present application is low, and when preparing the plastic sheet, the supporting protrusion can be formed in an integrated manner, which has an integrated visual effect, and the supporting protrusion is not easy to fall off or lose. Brief Description of the Figures

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application and more comprehensively understand the present application and its beneficial effects, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 Schematic structural diagram of a waveguide sheet module of a comparative implementation manner;

[0018] Figure 2 For Figure 1 Schematic structural diagram of the depression generated by the waveguide sheet module of the comparative implementation manner shown;

[0019] Figure 3 For Figure 1 Actual situation diagram of Newton's rings and adhesion generated by the waveguide sheet module of the comparative implementation manner shown;

[0020] Figure 4 Schematic structural diagram of an extrusion forming device for a plastic sheet of an implementation manner;

[0021] Figure 5 Schematic structural diagram of the first roller of Example 1;

[0022] Figure 6 For Figure 5 Cross-sectional view of the first roller shown along the A-A' section;

[0023] Figure 7 For Figure 6 Enlarged view of the dashed-line B area shown;

[0024] Figure 8 Schematic structural diagram of the first roller of Example 2;

[0025] Figure 9 For Figure 8 Cross-sectional view of the first roller shown along the A-A' section;

[0026] Figure 10 For Figure 9 Enlarged view of the dashed-line C area shown;

[0027] Figure 11 Schematic structural diagram of an extrusion mechanism;

[0028] Figure 12 Schematic flow diagram of a preparation method for a plastic sheet of a comparative implementation manner;

[0029] Figure 13 Actual situation diagram of Newton's rings generated by a waveguide sheet module due to the absence or detachment of some support protrusions;

[0030] Figure 14 Schematic structural diagram of a plastic sheet in an embodiment;

[0031] Figure 15 is Figure 14 Top view of the plastic sheet;

[0032] Figure 16 is Figure 14 Enlarged view of the dotted line D area shown in;

[0033] Figure 17 Schematic structural diagram of a waveguide sheet module in an embodiment. Specific embodiments

[0034] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0036] The term

[0037] Unless otherwise stated or there is a contradiction, the terms or phrases used in this application have the following meanings:

[0038] In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined. In this application, "several" means at least one, such as one, two, etc., unless otherwise specifically defined.

[0039] In this application, the terms "optionally", "optional", "option" mean that it may or may not be present, that is, it refers to any one of two alternative schemes of "present" or "absent". If the term "optional" appears multiple times in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction relationship, each "optional" is independent of each other.

[0040] In this application, in relation to "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumerative description and should be understood not to constitute a closed limitation on quantity.

[0041] In this application, when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. It should also be understood that when interpreting the connection relationship or positional relationship of elements, although not explicitly described, the connection relationship and positional relationship are interpreted to include an error range, and this error range should be within the acceptable deviation range of a specific value determined by those skilled in the art.

[0042] Currently, the concept of the metaverse is becoming increasingly popular, and the related industries have also started to develop rapidly. The metaverse provides an immersive experience based on extended reality technology, generates a mirror image of the real world based on digital twin technology, builds an economic system based on blockchain technology, closely integrates the virtual world and the real world in the economic system, social system, and identity system, and allows each user to produce content and edit the world. Among them, extended reality technology (XR) is the foundation of the metaverse, including virtual reality technology (VR), augmented reality technology (AR), and mixed reality technology (MR), etc.

[0043] The above technologies can be experienced through smart wearable devices. For example, AR technology can be experienced through augmented reality (AR) devices. The waveguide module is an important component of an AR device, which is used to transmit the optical signal incident on the waveguide module and perform one-dimensional pupil expansion or two-dimensional pupil expansion on the image information in the optical signal.

[0044] In a comparative embodiment, a waveguide module is provided. Please refer to Figure 1, the waveguide sheet module 100 includes a waveguide sheet 11, a protective cover plate 12, and an adhesive layer 13. The waveguide sheet 11 includes a light conduction layer 111 and a grating structure 112 located on the surface of the light conduction layer 111. The protective cover plate 12 is disposed at an interval on the side of the grating structure 112 facing away from the light conduction layer 111. The adhesive layer 13 is located between the waveguide sheet 11 and the protective cover plate 12, connecting the peripheries of the waveguide sheet 11 and the protective cover plate 12 and surrounding the grating structure 112 therein. At this time, the middle area of the protective cover plate 12 is suspended, and the grating structure 112 is located in a completely sealed space. Since the protective cover plate 12 is usually attached at room temperature, when the waveguide sheet module 100 is in a low-temperature environment, due to the thermal expansion and contraction effect of the gas, the air pressure in the sealed space where the grating structure 112 is located decreases. If the protective cover plate 12 is made of a material with good rigidity such as glass or sapphire, the suspended protective cover plate 12 is not easily recessed. However, if the protective cover plate 12 is a plastic sheet, due to the poor rigidity of the plastic sheet, the suspended plastic sheet is prone to generate a depression from the periphery to the center. In addition, when there is dirt on the surface of the waveguide sheet module 100 and the surface of the waveguide sheet module 100 is wiped, if the protective cover plate 12 is a plastic sheet, due to the poor rigidity of the plastic sheet, the suspended protective cover plate 12 will be bent by the force and also generate a depression. Please refer to Figure 2 , Figure 2 FIG. Figure 2 is a schematic structural diagram of the waveguide sheet module 100 generating a depression when the protective cover plate 12 is made of a plastic material. When the distance between the protective cover plate 12 and the waveguide sheet 11 is very small or they are attached, Newton's rings and adhesion phenomena will occur between the protective cover plate 12 and the waveguide sheet 11. Among them, the principle of the generation of Newton's rings is as follows: When the protective cover plate 12 is recessed and attached to the waveguide sheet 11, a nano-scale air film will be generated around the attachment area of the protective cover plate 12 and the waveguide sheet 11. When ambient light is incident, part of the light will be directly reflected by the surface of the protective cover plate 12, and another part of the light will pass through the protective cover plate 12 and irradiate on the waveguide sheet 11 and be reflected by the surface of the waveguide sheet; since light has wave properties, when the thickness of the air film is 1 / 4 of the wavelength of light, at this time, the light reflected by the surface of the waveguide sheet and the light reflected by the surface of the protective cover plate 12 have a phase difference of 1 / 2 wavelength. Also, since these two beams of light are the same incident light and are coherent light, when the phase difference between these two beams of light is 1 / 2 wavelength, they will cancel each other out. In addition, since the incident ambient light is mixed light and different colors of light have different wavelengths, for example, when the thickness of the air film is 1 / 4 of the wavelength of green light, at this time, the green light part in these two beams of light in this area cancels each other out, leaving only the mixed light of the remaining visible light, showing a colored ring; similarly, when the thickness of the air film is 1 / 4 of the wavelength of other colors of light, other colors will be shown; in summary, around the attachment area, Newton's rings of respective colors will appear. Please refer to Figure 3 , Figure 3This is a live picture of Newton's rings 1 and adhesion 2 generated by the waveguide sheet module when a plastic material is used as the protective cover plate 12. From Figure 3 As can be seen, Newton's rings 1 are a series of colored rings. The appearance of Newton's rings will seriously affect the transmittance of the waveguide sheet module 100, causing great interference to users when using AR devices.

[0045] In addition to the problem that the plastic sheet will sag due to suspension when used as the protective cover plate in the above-mentioned waveguide sheet module, when it is applied in other fields and connected to other components in some areas, there is also a problem that the plastic sheet in other areas sags due to suspension, affecting the product performance. And because the plastic sheet has the characteristic of light weight, it has great potential for weight reduction. Therefore, it is necessary to solve the problem of sagging of the plastic sheet in the suspended area.

[0046] The first aspect of this application provides an extrusion forming device for a plastic sheet. Please refer to Figure 4 , in one embodiment, the extrusion forming device 200 for a plastic sheet includes an extrusion mechanism 21 and a roller mechanism 22; the roller mechanism 22 includes a first roller 221 and a second roller 222 that are parallel and spaced apart. The first roller 221 and the second roller 222 are used to cooperate with each other to form the plastic blank 31 extruded from the extrusion mechanism 21 into a plastic sheet 30, and the gap between the first roller 221 and the second roller 222 is smaller than the thickness of the plastic blank 31; a groove is provided on the surface of the first roller 221 along the circumferential direction, and the groove is used to form a support protrusion for preventing the plastic sheet 30 from sagging due to the suspension of some areas.

[0047] The extrusion forming device 200 of this embodiment includes an extrusion mechanism 21 and a roller mechanism 22. The extrusion mechanism 21 can extrude the plastic blank 31, and the extruded plastic blank 31 can be formed into a plastic sheet 30 under the extrusion of the roller mechanism 22. Among them, a groove is provided on the surface of the first roller 221 in the roller mechanism 22 along the circumferential direction. When the relatively thick plastic blank 31 enters the gap between the first roller 221 and the second roller 222 with a relatively small gap, under the extrusion of the first roller 221 and the second roller 222, a part of the plastic blank 31 enters the groove of the first roller 221, and after forming, a plastic sheet 30 with support protrusions can be obtained. The formed support protrusions can prevent the plastic sheet from sagging due to the suspension of some areas and avoid the influence of the appearance of sagging on the product performance.

[0048] Optionally, the depth of the groove is equal to the overhang of the plastic sheet corresponding to its area. The number of grooves can be multiple, and the depth of each groove can be set according to the overhang of the plastic sheet corresponding to it, which can better prevent the suspended area of the plastic sheet from being sunken under low temperature or external force. It can be understood that the overhang refers to the distance between the bottom surface of the plastic sheet in the suspended area and the surface of other components connected to the plastic sheet in the suspended area.

[0049] The plastic sheet 30 prepared by the extrusion forming device 200 of the present application can be used as a protective cover plate in fields such as waveguide sheet modules, which can avoid the generation of Newton's rings and adhesion phenomena between the waveguide sheet and the plastic sheet 30, and the user experience is good.

[0050] In Example 1, please refer to Figures 5 to 7 , a plurality of grooves 2211 are arranged on the surface of the first roller 221 along the circumferential direction. The number of the grooves 2211 is multiple, and the multiple grooves 2211 are arranged in an array, and the multiple grooves 2211 are used to form supporting protrusions that abut against the light conduction layer. The multiple grooves 2211 arranged in an array can correspondingly form supporting protrusions arranged in an array, which is beneficial to make the supporting force distribution of the plastic sheet more uniform, and can prevent the plastic sheet from being sunken when the plastic sheet is subjected to external forces such as atmospheric pressure or wiping.

[0051] Figure 5 In the structure shown, the multiple grooves 2211 are periodically distributed, and the periodically distributed multiple grooves 2211 can form correspondingly periodically distributed supporting protrusions. Optionally, the multiple grooves are at least arranged in an array at a position close to the center on the circumferential surface of the first roller 221; in other examples, the multiple grooves 2211 can also be distributed on the entire circumferential surface of the first roller 221.

[0052] Optionally, the shape of the groove 2211 can be, but is not limited to, regular shapes such as hemispherical, conical, cylindrical, etc., and can also be an irregular shape. Figure 5 In the structure shown, the shape of the groove 2211 is hemispherical, which should not be construed as a limitation on the shape of the groove.

[0053] Optionally, please refer to Figure 7, the depths of the multiple grooves 2211 are each independently h1, and the h1 satisfies: 0.01 mm ≤ h1 ≤ 0.2 mm. For example, h1 is 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm. The wavelength of visible light is 380 nm to 750 nm. The depth h1 of the groove 2211 is greater than 0.01 mm, the height of the corresponding support protrusion is greater than 0.01 mm, and the air film between the plastic sheet and the waveguide sheet is also greater than 0.01 mm. The phase difference between the two beams of light exceeds 10 times the wavelength, and the light energy of the interference is weak. At this time, it is difficult to observe Newton's rings with the naked eye. Therefore, adopting this solution can basically solve the problem of Newton's rings. When h1 is too small, the corresponding support protrusions formed cannot produce sufficient support effect. When the plastic sheet is recessed, the thickness of the air film between the plastic sheet and the waveguide sheet is small, and there is still a risk of generating visible Newton's rings with the naked eye; when h1 is too large, the corresponding support protrusions formed are too obvious and visible to the naked eye, affecting the wearing visual experience.

[0054] Optionally, please refer to Figure 7 , the distance between the two farthest points on the area surrounded by the orthographic projection of the multiple grooves 2211 on the surface of the first roller 221 is each independently d1, and the d1 satisfies: 0.01 mm ≤ d1 ≤ 0.2 mm. For example, d1 is 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm. When the shape of the groove is hemispherical, d1 is the diameter of the hemisphere. When d1 is too small, the corresponding support protrusions formed cannot produce sufficient support effect. When the plastic sheet is recessed, the thickness of the air film between the plastic sheet and the waveguide sheet is small, and there is still a risk of generating visible Newton's rings with the naked eye; when d1 is too large, the corresponding support protrusions formed are too obvious and visible to the naked eye, affecting the wearing visual experience.

[0055] Optionally, please refer to Figure 5 , the shortest distance between any two adjacent grooves 2211 is s1, and the s1 satisfies: 0.5 mm ≤ s1 ≤ 10 mm. For example, s1 is 0.5 mm, 1 mm, 3 mm, 5 mm, 8 mm, 10 mm. When s1 is too small, the density of the grooves 2211 is too large, affecting the transmittance of the waveguide module and the wearing visual performance; when s1 is too large, the density of the grooves 2211 is too small, and the supporting force of the corresponding support protrusions formed is insufficient, and there is still a risk of generating Newton's rings in the suspended area between adjacent support protrusions.

[0056] In Example 1, the shapes of the multiple grooves 2211 are the same, all being hemispherical. The dimensions (depth h1 and diameter d1) of each groove are the same, and the distance between any two adjacent grooves is equal (i.e., the distance s1 between any two adjacent grooves horizontally and vertically is equal). The multiple corresponding support protrusions can provide uniform support force to prevent the plastic sheet from sagging.

[0057] In Example 2, please refer to Figures 8 to 10 , on the surface of the first roller 221, grooves 2212 are arranged along the circumferential direction. The number of the grooves 2212 is multiple, and the multiple grooves 2212 are randomly distributed. The multiple grooves 2212 are used to form support protrusions for abutting against the grating structure. Among them, the grating structure includes an input grating and an output grating arranged at intervals. The input grating is used to couple an optical signal into the optical conduction layer, and the output grating is used to couple the optical signal transmitted through the optical conduction layer out of the waveguide sheet. The output grating includes multiple output sub-gratings arranged at intervals. The multiple grooves 2212 are used to form support protrusions for abutting against some of the output sub-gratings. When the plastic sheet is subjected to external forces such as atmospheric pressure or wiping, the sagging of the plastic sheet can be prevented. If the multiple grooves 2212 are arranged periodically, an additional period will be introduced to the output grating, and additional diffraction orders of light will be generated, thereby generating ghost images. The random distribution of the multiple grooves 2212 can avoid the generation of ghost images and enable the waveguide sheet to have a better display effect.

[0058] Optionally, please refer to Figure 10 , the depths of the multiple grooves 2212 are independently h2, and the h2 satisfies: 0.01 mm ≤ h1 ≤ 0.05 mm. For example, h2 is 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm. The wavelength of visible light is from 380 nm to 750 nm. The depth h2 of the groove 2212 is greater than 0.01 mm, the height of the corresponding support protrusion is greater than 0.01 mm, and the air film between the plastic sheet and the waveguide sheet is also greater than 0.01 mm. The phase difference between the two beams of light exceeds 10 times the wavelength, and the light energy undergoing interference is weak. At this time, it is very difficult for the naked eye to observe Newton's rings. Therefore, adopting this solution can basically solve the problem of Newton's rings. When h2 is too small, the corresponding support protrusions formed cannot produce sufficient support effect. When the plastic sheet sags, the thickness of the air film between the plastic sheet and the waveguide sheet is small, and there is still a risk of generating visible Newton's rings with the naked eye; when h2 is too large, the corresponding support protrusions are too obvious and visible to the naked eye, affecting the wearing visual experience.

[0059] Optionally, the output grating is a two-dimensional grating (i.e., a dot matrix grating), and the shape and size of the region surrounded by the positive projection of the groove 2212 on the surface of the first roller 221 are the same as the shape and size of the region surrounded by the positive projection of the output sub-grating on the optical conduction layer.

[0060] Optionally, the distance between any two adjacent grooves 2212 is more than 10 times the period of the outcoupling grating, for example, between 10 and 1000 times; specifically, it can be, but not limited to, 10, 20, 50, 100 times, etc. This can avoid introducing new periods as much as possible and prevent the generation of ghost images.

[0061] Optionally, the average distribution density of the grooves is in the range of 10 / mm 2 ~100 pieces / mm 2 . For example, the average distribution density of grooves ranges from 10 / mm 2 、20pcs / mm 2 、30pcs / mm 2 、40pcs / mm 2 、50pcs / mm 2 、60 pieces / mm 2 、70 pieces / mm 2 、80 pieces / mm 2 、90 pieces / mm 2 、100pcs / mm 2 , etc. If the average distribution density of the grooves is too small, the corresponding support protrusions will not provide sufficient support. When the plastic sheet is subjected to external force, it is still possible that the plastic sheet and the waveguide sheet will fit together, increasing the risk of Newton rings. If the average distribution density of the grooves is too large, the transmittance of the waveguide sheet module will be too low, affecting the visual experience of wearing.

[0062] Optionally, the gap between the first roller and the second roller is t1, and t1 satisfies: 0.1mm≤t1≤1mm. For example, t1 is 0.1mm, 0.2mm, 0.4mm, 0.5mm, 0.8mm, 1mm. The gap between the first roller and the second roller is the thickness of the plastic sheet after forming. It can be understood that the gap between the first roller and the second roller refers to the distance between the surface of the first roller excluding the groove and the surface of the second roller.

[0063] In other embodiments, the second roller can also be replaced by other extrusion members, for example, the extrusion member is a sheeting belt. The gap t1 between the extrusion member and the first roller meets the above conditions.

[0064] Please see Figure 11, along the direction from the feed end to the discharge end, the extrusion mechanism 21 is successively provided with a feeding device 211, a screw extrusion device 212, a die pre-forming device 213 and a discharge device 214; after the material enters from the feeding device 211, it enters the screw extrusion device 212. As the screw rotates, the material pushed forward by the screw threads is subjected to a great extrusion force. At the same time, the material is also subjected to the heating of the barrel and the shearing action of the screw, and the material is fully plasticized. Since the screw has been rotating steadily and continuously, the plasticized material (melt) is extruded into the die pre-forming device 213 for pre-forming to obtain a semi-solid plastic blank, which is extruded through the discharge device 214.

[0065] Please refer to Figure 4 , along the advancing direction of the plastic sheet 30, the extrusion forming device 200 further includes a cooling mechanism (not shown in the figure), a traction mechanism (not shown in the figure) and a winding mechanism 23 arranged in sequence. Among them, the cooling mechanism is used for cooling the plastic sheet. The traction mechanism is used for traction the plastic sheet to move as required. The winding mechanism 23 is used for collecting the plastic sheet 30.

[0066] In a comparative embodiment, a method for preparing a plastic sheet with support protrusions is provided. Please refer to Figure 12 , the method for preparing a plastic sheet with support protrusions is as follows:

[0067] S10. Provide a plate body and a silk screen printing plate, and the silk screen printing plate has a plurality of through holes arranged in an array; attach the plate body to the silk screen printing plate.

[0068] S20. Drop UV glue on the surface of the silk screen printing plate facing away from the plate body.

[0069] S30. Use a squeegee to completely fill the plurality of through holes on the silk screen printing plate with UV glue;

[0070] S40. Separate the silk screen printing plate from the plate body so that a plurality of glue droplets arranged in an array are formed on the plate body;

[0071] S50. Perform UV light curing to make the glue droplets form support protrusions to obtain a plastic sheet.

[0072] The method of the above comparative embodiment has the following disadvantages: 1) Each plastic sheet needs to be produced by printing, so the production efficiency is low and the production cost is high; 2) Since it needs to be produced by printing, the cleanliness and dyne value of the surface of the plate body have high requirements before printing, otherwise it may cause some support protrusions to be missing or detached, resulting in poor local support ability of the waveguide sheet module, and then generating Newton's rings. Please refer to Figure 13, the waveguide sheet module serves as the lens of the AR glasses, and some of the support protrusions are missing or detached, and Newton's rings 3 are observed on the lens; 3) Since the material of the support protrusion formed by printing and the material of the plate body belong to different materials, there are also differences in refractive index. Compared with the case where the refractive indices are the same, different refractive indices make the support protrusions on the plastic sheet easier to identify, so there are slight defects in appearance.

[0073] Compared with the above comparative implementation, when preparing the plastic sheet 30 by the extrusion molding device 200 of the embodiment of the present application, the support protrusion can be integrally formed, and the material of the support protrusion is the same as that of the plate body. On the one hand, subsequent printing is not required, saving processes and reducing costs. On the other hand, the plastic sheet 30 has an integrated visual effect. At the same time, the support protrusions are not easily dropped or missing.

[0074] The second aspect of the present application provides a plastic sheet, please refer to Figures 14 to 16 , in one embodiment, the plastic sheet 30 includes a plate body 30A and support protrusions 30B located on the surface of the plate body 30A and integrally formed with the plate body 30A. The plastic sheet 30 is prepared by the extrusion molding device 200 as described above.

[0075] It can be understood that the shape and size of the support protrusion 30B correspond to the shape and size of the groove.

[0076] In one example, the support protrusion 30B and Figure 5corresponds to the groove 2211 shown. The number of the support protrusions 30B is multiple, and the height of each of the multiple support protrusions is h3 independently, and the h3 satisfies: 0.01 mm ≤ h3 ≤ 0.2 mm. For example, h3 is 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm. The distance between the two points farthest apart on the region surrounded by the orthographic projection of the multiple support protrusions 30B on the surface of the plate body is d3 independently, and the d3 satisfies: 0.01 mm ≤ d3 ≤ 0.2 mm. For example, d3 is 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm. When the shape of the groove is hemispherical, d3 is the diameter of the hemispherical shape. The shortest distance between any two adjacent support protrusions 30B is s3, and the s3 satisfies: 0.5 mm ≤ s3 ≤ 10 mm. For example, s3 is 0.5 mm, 1 mm, 3 mm, 5 mm, 8 mm, 10 mm. In this example, the shapes of the multiple support protrusions 30B are the same, all being hemispherical, the sizes (height h3, diameter d3) of each support protrusion are the same, and the distances between any two adjacent grooves are equal (that is, the distances s3 between any two adjacent grooves horizontally and vertically are equal), which can provide uniform supporting force and prevent the plastic sheet from sagging.

[0077] In other examples, the support protrusion 30B corresponds to Figure 8 the groove 2212 described above. For details, refer to the above, and details will not be repeated here.

[0078] Optionally, the material of the plastic sheet includes at least one of polymethyl methacrylate (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET). In this embodiment, the materials of the plate body and the support protrusions are the same, including at least one of PMMA, PC, and PET. For example, the material is PMMA, PC, PET, or a composite material of PMMA and PC.

[0079] Optionally, for the composite material of PMMA and PC, the plastic cover plate has opposite first and second surfaces, the hardness of the first surface is greater than that of the second surface, and the support protrusion is located on the first surface. The hardness of the first surface is greater than that of the second surface, and it contains more PMMA content, and has better supportability.

[0080] The above plastic sheet can be used as a protective cover plate in the waveguide sheet module to solve the problems of sagging, even Newton's rings and adhesion caused by the suspension of some regions of the plastic sheet. At the same time, the setting of the above support protrusion will not affect the optical display effect, and the user experience is good.

[0081] The third aspect of the present application provides a waveguide sheet module. Please refer to Figure 17 , in one embodiment, the waveguide sheet module 400 includes a waveguide sheet 41, a first plastic sheet 42, a first connecting member 43, a second plastic sheet 44, and a second connecting member 45; the waveguide sheet 41 includes a light conduction layer and a grating structure located on the surface of the light conduction layer; the first plastic sheet 42 and the second plastic sheet 44 are prepared by the above-mentioned extrusion forming device; the first plastic sheet 42 includes a first plate body and a first support protrusion located on the surface of the first plate body and integrally formed with the first plate body. The first plate body is located on the side of the grating structure away from the light conduction layer. The first support protrusion faces the waveguide sheet 41 and abuts against the grating structure; the first connecting member 43 is located between the first plastic sheet 42 and the waveguide sheet 41 for connecting the two and surrounding the grating structure; the second plastic sheet 44 includes a second plate body and a second support protrusion located on the surface of the second plate body and integrally formed with the second plate body. The second plate body is located on the side of the light conduction layer away from the grating structure. The second support protrusion faces the waveguide sheet 41 and abuts against the light conduction layer. The second connecting member 45 is located between the second plastic sheet 44 and the waveguide sheet 41 for connecting the two.

[0082] In other embodiments, the first support protrusion faces the waveguide sheet 41 and abuts against the light conduction layer.

[0083] Optionally, the first connecting member and the second connecting member are each independently an optical adhesive layer (OCA).

[0084] The fourth aspect of the present application provides an augmented reality device. In one embodiment, the augmented reality device includes a projection optical machine and the waveguide sheet module as described above;

[0085] The projection optical machine is used to project an optical signal, and the optical signal includes image information;

[0086] The waveguide sheet module is used to transmit the optical signal.

[0087] It can be understood that the augmented reality device can be an augmented reality glasses, an augmented reality helmet, an augmented reality mask, etc.

[0088] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0089] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An extrusion molding device for a plastic sheet, characterized in that: It includes an extrusion mechanism and a roller mechanism; the roller mechanism includes a first roller and an extrusion piece which are arranged in parallel and at intervals, the first roller and the extrusion piece are used to cooperate with each other to form the plastic blank extruded from the extrusion mechanism into a plastic plate, and the gap between the first roller and the extrusion piece is smaller than the thickness of the plastic blank; the surface of the first roller is provided with a groove along the circumferential direction, the groove is used to form a supporting protrusion to prevent the plastic plate from being sunken due to partial suspension.

2. The extrusion molding device according to claim 1, characterized in that: The depth of the groove is equal to the overhang of the plastic sheet corresponding to the area thereof.

3. The extrusion molding device according to claim 1, characterized in that: There are multiple grooves, which are arranged in an array, and are used to form supporting protrusions that abut against the light conductive layer.

4. The extrusion molding device according to claim 3, characterized in that: At least one of the following conditions is met: 1) The depth of each of the plurality of grooves is independently h1, and h1 satisfies: 0.01 mm ≤ h1 ≤ 0.2 mm; 2) The distance between the two farthest points on the area enclosed by the orthographic projection of the plurality of grooves on the surface of the first roller is independently d1, and d1 satisfies: 0.01 mm ≤ d1 ≤ 0.2 mm; 3) The shortest distance between any two adjacent grooves is s1, and s1 satisfies: 0.5mm≤s1≤10mm.

5. The extrusion molding device according to claim 1, characterized in that: There are multiple grooves, which are randomly distributed and used to form supporting protrusions that abut against the grating structure.

6. The extrusion molding device according to claim 5, characterized in that: The depths of the plurality of grooves are each independently h2, and h2 satisfies: 0.01 mm ≤ h1 ≤ 0.05 mm.

7. The extrusion molding device according to claim 1, characterized in that: The average distribution density of the grooves is 10 / mm 2 ~100 pieces / mm 2 .

8. The extrusion molding device according to any one of claims 1 to 7, characterized in that: Includes at least one of the following features: 1) The extrusion member is selected from a second roller or a sheeting belt; 2) The gap between the first roller and the extrusion member is t1, and t1 satisfies: 0.1 mm ≤ t1 ≤ 1 mm; 3) The extrusion mechanism is provided with a feeding device, a screw extrusion device, a mold pre-forming device and a discharging device in sequence; the screw extrusion device is used to plasticize the material entering from the feeding device; the mold pre-forming device is used to pre-form the plasticized material into a plastic blank; 4) Along the advancing direction of the plastic sheet, the extrusion forming device further includes a cooling mechanism, a traction mechanism and a winding mechanism which are arranged in sequence.

9. A plastic sheet, characterized in that: It comprises a plate body and a supporting protrusion located on the surface of the plate body and integrally formed with the plate body, and the plastic plate is prepared by the extrusion molding device described in any one of claims 1 to 8.

10. The plastic sheet material according to claim 9, characterized in that: The material of the plastic plate includes at least one of polymethyl methacrylate, polycarbonate and polyethylene terephthalate.

11. The plastic sheet material according to claim 10, characterized in that: The plastic plate is made of a composite material of polymethyl methacrylate and polycarbonate, and has a first surface and a second surface opposite to each other. The hardness of the first surface is greater than that of the second surface. The supporting protrusion is located on the first surface.

12. A waveguide module, characterized in that: It comprises a waveguide plate, a first plastic sheet and a first connecting member; the waveguide plate comprises a light-conducting layer and a grating structure located on the surface of the light-conducting layer; the first plastic sheet is prepared by an extrusion molding device described in any one of claims 1 to 8; the first plastic sheet comprises a first plate body and a first supporting protrusion located on the surface of the first plate body and integrally formed with the first plate body, the first plate body is located on the side of the grating structure away from the light-conducting layer, the first supporting protrusion faces the waveguide plate and abuts against the light-conducting layer or the grating structure; the first connecting member is located between the first plastic sheet and the waveguide plate to connect the two and surround the grating structure.

13. The waveguide module according to claim 12, characterized in that: It also includes a second plastic sheet and a second connecting member; the second plastic sheet is prepared by the extrusion molding device described in any one of claims 1 to 8; the second plastic sheet includes a second plate body and a second supporting protrusion located on the surface of the second plate body and integrally formed with the second plate body, the second plate body is located on the side of the light conductive layer away from the grating structure, the second supporting protrusion faces the waveguide plate and abuts against the light conductive layer, and the second connecting member is located between the second plastic sheet and the waveguide plate to connect the two.

14. An augmented reality device, characterized in that: A waveguide module comprising a projection optical machine and any one of claims 12 to 13; The optical projection machine is used to project a light signal, wherein the light signal includes image information; The waveguide module is used to transmit the optical signal.

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