Processing method of flat lens

Abstract

The present invention discloses a method for processing a flat lens. During the processing of the flat lens, spacers need to be formed on a substrate by embossing. The method comprises the following steps: fixing the substrate on a fixed base and covering the surface of the substrate with an ink layer; covering the side of the substrate covered with the ink layer with an embossing template, and providing a protrusion on the side of the embossing template facing the substrate; pressing the embossing template and the substrate against each other, and squeezing the area on the ink layer facing the protrusion into a concave area, and forming an ink block in the concave area of ​​the ink layer; removing the embossing template from the substrate, and solidifying the ink block to form a spacer. This processing method greatly improves the molding efficiency of the spacer and can maintain parameters such as the height, shape and spacing of the spacer. Since the ink layer is compacted on the substrate by the embossing template, the ink block can be very firmly bonded to the substrate after solidification. The spacer formed in this way is not easy to shift on the substrate, and the arrangement of the spacer in subsequent processes can remain unchanged.

Description

Technical Field

[0001] The present invention relates to the field of optical equipment manufacturing, and in particular to a method for processing a flat lens. Background Art

[0002] A flat lens utilizes two layers of periodically spaced, orthogonal arrayed waveguides, causing light to undergo a total internal reflection (TIR) ​​in each of the two layers. Due to the orthogonal rectangular structure, the angle of incidence during the first TIR and the angle of exit during the second TIR are identical. After passing through the flat lens, all light rays within the light source's divergence angle converge to a spatial location symmetrical to the flat surface, resulting in a 1:1 floating real image. However, this imaging structure requires high processing technology; if the reflecting surfaces are not parallel or perpendicular, the resulting floating real image is susceptible to distortion. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for processing a flat lens to improve the processing efficiency and precision of spacers, thereby improving imaging effects.

[0004] According to an embodiment of the present invention, a method for processing a flat lens is provided. The flat lens is formed by stacking two optical waveguide stacks along the Z direction. Each optical waveguide stack is composed of a single row of multiple-row sub-waveguides with rectangular cross-sections. The two optical waveguide stacks include: a first optical waveguide stack and a second optical waveguide stack. The sub-waveguides of the first optical waveguide stack extend along the X direction and form multiple rows along the Y direction. The sub-waveguides of the second optical waveguide stack extend along the Y direction and form multiple rows along the X direction. The X, Y, and Z directions are perpendicular to each other. Each optical waveguide stack is formed by stacking transparent parallel flat plates coated with a reflective film on both sides. The transparent parallel flat plates serve as a first substrate. When the two optical waveguide stacks are stacked to form the flat lens, the optical waveguide stack serves as a second substrate. The first and second substrates are both substrates. A plurality of spacers are provided between two adjacent substrates when stacked. At least one layer of the spacers is formed on the substrate by embossing.

[0005] Forming the spacers on the substrate by embossing comprises the following steps:

[0006] S1: fixing the substrate on a fixed base and covering the surface of the substrate with an ink layer;

[0007] S2: Covering the side of the substrate covered with the ink layer with an imprint template, wherein the imprint template is provided with a protrusion on the side facing the substrate, and pressing the imprint template and the substrate against each other, so that the area of ​​the ink layer facing the protrusion is squeezed into a concave area, and the concave area of ​​the ink layer forms an ink block;

[0008] S3: removing the imprint template from the substrate and solidifying the ink block to form the spacer.

[0009] According to the flat lens processing method of the present invention, by embossing spacers onto a substrate, spacer forming efficiency is significantly improved. Furthermore, by adjusting the size of the protrusions on the embossing template, parameters such as the spacer height, shape, and spacing can be maintained. Because the ink layer is pressed onto the substrate by the embossing template, the ink block adheres very firmly to the substrate after curing. The spacers thus formed are less likely to shift on the substrate, and their arrangement can be maintained in subsequent steps.

[0010] In some embodiments, in step S3, the ink block is cured under ultraviolet light, the wavelength of the ultraviolet light is 200-450 nm, and the curing conditions are: a curing environment temperature of 19° C.-25° C., a curing environment humidity of less than 50%, and ventilation with a wind speed ranging from 0.1 m / s to 2 m / s to remove gas volatiles generated by ink curing.

[0011] Specifically, when the ink body is cured under ultraviolet light in step S3, the wavelength of the ultraviolet light is 365nm or 395nm, or the ultraviolet light is a mixed light composed of 365nm and 395nm, and the irradiance of the ultraviolet light is 20 - 1500mW / cm 2 The total energy of the ultraviolet light is required to be 2000-5000mJ / cm 2 .

[0012] Specifically, the ink layer is a light-curing adhesive or a heat-curing adhesive.

[0013] In some embodiments, the viscosity of the ink before curing is 10,000-50,000 cps, and the Shore hardness of the spacer after curing is 70A-90D; the ink layer is one or more of epoxy resin, acrylic resin, chlorinated acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyurethane and polyamide resin.

[0014] Specifically, the ambient temperature in step S2 is maintained at 19-25°C.

[0015] In some embodiments, the spacers between adjacent first substrates have a height of 10 to 100 μm and a distance of 2 to 3 mm between adjacent spacers when the ink viscosity is 10,000 to 30,000 cps and the Shore hardness of the spacers after curing is 25D to 40D.

[0016] The spacers between adjacent first substrates have an ink viscosity of 10,000-30,000 cps and a Shore hardness of 70A-25D after curing, a height of the spacers of 10-100 μm, and a distance between adjacent spacers of 0.5-1 mm.

[0017] The spacers between adjacent second substrates have an ink viscosity of 10,000-50,000 cps and a Shore hardness of 30D-90D after curing. The height of the spacers is 50-500 μm, and the distance between adjacent spacers is 10-50 mm.

[0018] In some embodiments, the fixed base is provided with a plurality of fasteners, which are fastened to the substrate, thereby conveniently fixing the substrate to the fixed base, facilitating assembly and disassembly of the substrate, and accelerating the efficiency of processing spacers on the substrate.

[0019] In some embodiments, after at least two substrates are stacked with the spacer, a glue pool is connected. Glue in the glue pool is filled between adjacent substrates by pressure differential or gravity. This allows the spacer to be fixed relative to the substrates during glue pouring, preventing the spacer from shifting during the pouring process and maintaining an appropriate spacing between the spacers after pouring.

[0020] In some embodiments, the protrusions are formed in a mesh shape, and the outer contour of the protrusions completely covers the ink layer.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a general structural diagram of a flat lens according to an embodiment of the present application.

[0024] Figure 2 yes Figure 1 A partial enlarged view of K in the side view.

[0025] Figure 3 1 is an exploded view of a flat lens according to an embodiment of the present application.

[0026] Figure 4 1 is a schematic structural diagram of two orthogonal optical waveguide stacks along the Z direction according to an embodiment of the present application.

[0027] Figure 5 FIG. 1 is a schematic diagram of an imaging process of two orthogonal optical waveguide stacks according to an embodiment of the present application.

[0028] Figure 6 FIG. 1 is a schematic diagram of imaging in the X direction when a light source image passes through a single-layer optical waveguide stack according to an embodiment of the present application.

[0029] Figure 7 yes Figure 6 The diagram shows the imaging of a light source image in a three-dimensional direction when the light source image passes through a single-layer optical waveguide stack.

[0030] Figure 8 This is a principle diagram of the imaging optical path when a light source image passes through two orthogonal optical waveguide stacks according to an embodiment of the present application.

[0031] Figure 9 FIG. 1 is a schematic diagram of a processing method for an optical waveguide stack in one embodiment (the adhesive layer is omitted in the figure).

[0032] Figure 10 FIG. 1 is a schematic diagram of a processing method for an optical waveguide stack in another embodiment (the adhesive layer is omitted in the figure).

[0033] Figure 11 FIG. 1 is a schematic diagram of a spacer processing process according to an embodiment.

[0034] Reference numerals:

[0035] 1. Flat lens;

[0036] 10. Optical waveguide stack; 11. First optical waveguide stack; 12. Second optical waveguide stack;

[0037] 101. sub-waveguide; 102. spacer; 103. adhesive layer;

[0038] 30. Protective cover; 31. First cover; 32. Second cover;

[0039] L1, center normal;

[0040] P1, image; P2, floating real image;

[0041] 51. Substrate; 52. Fixed base; 521. Fastener; 53. Imprinting template; 531. Protrusion; 55. Ink layer; 551. Ink block. DETAILED DESCRIPTION

[0042] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0043] A method for manufacturing the flat lens 1 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0044] Before describing the processing method of the flat lens 1 , the structure of the flat lens 1 is briefly introduced here.

[0045] The two opposite sides of the flat lens 1 are the image source side and the viewing side, that is, the light source of the image P1 is located on the image source side. The image P1 passes through the flat lens 1 and can form a floating real image P2 on the viewing side. The floating real image P2 is a real image suspended in the air. Figure 1-Figure 3 As shown, the flat lens 1 is an optical structure that utilizes two periodically distributed, orthogonal optical waveguide stacks 10, causing light to undergo a total internal reflection (TIR) ​​once in each of the two layers. Because the two layers of optical waveguide stack 10 are orthogonal rectangular structures, the angle of incidence during the first TIR and the angle of exit during the second TIR are identical. After passing through the flat lens 1, light within the divergent angle of the light source converges toward the viewing side, resulting in a floating real image P2 with a 1:1 ratio to the image P1.

[0046] In order to deepen the understanding of the technical solution of this application, the following Figures 1-8 , while describing the basic structure of the flat lens 1, its imaging principle is explained.

[0047] See Figure 1-Figure 3 The flat lens 1 includes two optical waveguide stacks 10. Each optical waveguide stack 10 is composed of multiple rows of sub-waveguides 101 arranged in a single column. Each sub-waveguide 101 has a rectangular cross-section. The cross-section of a sub-waveguide 101 refers to a cross-section perpendicular to its length.

[0048] See Figure 2-Figure 4The two optical waveguide stacks 10 include: a first optical waveguide stack 11 and a second optical waveguide stack 12. The sub-waveguides 101 of the first optical waveguide stack 11 extend along the X direction and form multiple rows along the Y direction. The sub-waveguides 101 of the second optical waveguide stack 12 extend along the Y direction and form multiple rows along the X direction. The first optical waveguide stack 11 and the second optical waveguide stack 12 are arranged along the Z direction, and the X direction, the Y direction, and the Z direction are perpendicular to each other. Here, the extension direction of a sub-waveguide 101 is the length direction of the sub-waveguide 101. The length direction of a single sub-waveguide 101 in the first optical waveguide stack 11 is the X direction. The multiple sub-waveguides 101 in the first optical waveguide stack 11 are closely aligned and stacked along the Y direction, with the width direction of a single sub-waveguide 101 being the Y direction. The length direction of a single sub-waveguide 101 in the second optical waveguide stack 12 is the Y direction. The multiple sub-waveguides 101 in the second optical waveguide stack 12 are closely aligned and stacked along the X direction, with the width direction of a single sub-waveguide 101 being the X direction. The two optical waveguide stacks 10 are each in the shape of a flat plate. The arrangement direction from the first optical waveguide stack 11 to the second optical waveguide stack 12 is the Z direction, which is also the thickness direction of the flat lens 1. Note that, of the first and second optical waveguide stacks 11, 12, either the first or second optical waveguide stack 11 can be positioned closer to the image source, without limitation. The lengths of the two sub-waveguide layers 101 are perpendicular to each other, so the two optical waveguide stacks 10 are said to be orthogonal to each other.

[0049] Optionally, each sub-waveguide 101 is provided with a reflective film on both side surfaces in the width direction for total reflection of light. For example, a sub-waveguide 101 of the first optical waveguide stack 11 is provided with a reflective film on both side surfaces in the Y direction. Since the first optical waveguide stack 11 includes multiple sub-waveguides 101, multiple reflective films are arranged along the Y direction in the first optical waveguide stack 11. A sub-waveguide 101 of the second optical waveguide stack 12 is provided with a reflective film on both side surfaces in the X direction. Since the second optical waveguide stack 12 includes multiple sub-waveguides 101, multiple reflective films are arranged along the X direction in the second optical waveguide stack 12.

[0050] In some embodiments, such as Figure 1 and Figure 3 As shown, the flat lens 1 may further include a protective cover plate 30, which is used to support and protect the optical waveguide stack 10. The protective cover plate 30 may be provided on only one side of the flat lens 1, or on both sides of the flat lens 1. Specifically, the protective cover plate 30 is a transparent cover plate, and optionally, the protective cover plate 30 is a glass plate.

[0051] Figure 1-Figure 3The figure is a schematic diagram of the structure of a flat lens 1 in one embodiment. The flat lens 1 includes a pair of protective cover plates 30, namely a first cover plate 31 and a second cover plate 32. The flat lens 1 also includes two optical waveguide stacks 10, namely a first optical waveguide stack 11 and a second optical waveguide stack 12, located between the two protective cover plates 30. The X direction is the extension direction of the sub-waveguides 101 in the first optical waveguide stack 11, the Y direction is the extension direction of the sub-waveguides 101 in the second optical waveguide stack 12, and the Z direction is the thickness direction of the flat lens 1. Of course, in some solutions, the protective cover plates 30 can be eliminated, and other methods can be used to protect the optical waveguide stacks 10.

[0052] Alternatively, as Figure 4 As shown, the outer contour of the formed optical waveguide stack 10 is rectangular, and the angle θ between the extension direction of each sub-waveguide 101 and at least two sides of the outer contour of the optical waveguide stack 10 is further optionally satisfied: 30°≤θ≤60°, preferably θ=45°. At this angle, the floating real image P2 is clear and the afterimage is not obvious.

[0053] Here, the core imaging element of the flat lens 1 is the first optical waveguide stack 11 and the second optical waveguide stack 12. The first optical waveguide stack 11 and the second optical waveguide stack 12 include mutually orthogonal single-row multi-row sub-waveguides 101. The flat lens 1 is flat as a whole. Figure 5 As shown, it can achieve point-to-point aberration-free imaging of image P1.

[0054] The specific imaging principle is as follows: Here, the two optical waveguide stacks 10 are split. Figure 6 and Figure 7 As shown, taking the first optical waveguide stack 11 as an example, in a single-layer optical waveguide stack 10, a single point light from the image source side passes through the single-sided optical waveguide stack 10, is split and mirror-modulated by each row of sub-waveguides 101, and then reconverges on a straight line P1' parallel to the X-direction, forming a point-to-line one-dimensional imaging effect. Figure 6 As shown in FIG, the incident angle of a single point light on the image source side passing through a certain sub-waveguide 101 is δ, and the exit angle after reflection from the sub-waveguide 101 is δ'. The incident angle δ is equal to the exit angle δ'.

[0055] like Figure 8As shown, to achieve a point-intersection in both directions (X and Y), two optical waveguide stacks 10 are used in conjunction, with the sub-waveguides 101 arranged perpendicularly to each other. This allows for point-to-point modulation of the target light source image P1. Therefore, light rays from any direction passing through this mutually orthogonal double-layer optical waveguide stack 10 can be reconverged at symmetrical locations within the optical waveguide stack 10 to form a floating real image P2. The imaging distance m2 of floating real image P2 is the same as the distance m1 to the original image, achieving equidistant imaging. Furthermore, floating real image P2 is located in mid-air, eliminating the need for a projection screen or other support, and can be directly displayed in mid-air.

[0056] Therefore, this flat lens 1 can make a two-dimensional or three-dimensional light source directly form a real image in the air and realize a true holographic image. While achieving a large field of view, large aperture, high resolution, no distortion, and no dispersion, it also realizes naked-eye three-dimensional stereoscopic display characteristics.

[0057] In the drawings of the present application, the flat lens 1 is rectangular. However, in other embodiments of the present application, the shape of the flat lens 1 can also be adjusted as needed, for example, it can be circular, trapezoidal, etc., which is not limited here.

[0058] like Figure 2 As shown, in the same optical waveguide stack 10, two adjacent sub-waveguides 101 are separated by a plurality of spacers 102. The gaps between adjacent sub-waveguides 101, except for the spacers 102, are filled with a glue layer 103 formed by curing glue.

[0059] It is understood that the purpose of the adhesive layer 103 is to integrate adjacent sub-waveguides 101. The adhesive layer 103 is formed by glue, and the fluidity of the glue can be used to squeeze out the air (or nitrogen, etc.) in the gap to avoid excessive air residue and thus cause weak bonding.

[0060] However, since the adhesive layer 103 is formed by curing glue, the fluidity of the glue makes it difficult to precisely control the thickness of the adhesive layer 103, which can significantly reduce the parallelism of adjacent sub-waveguides 101. In the present application, however, adjacent sub-waveguides 101 are separated by multiple spacers 102. These spacers 102 maintain the parallelism of two adjacent sub-waveguides 101 and limit the width of the gap between adjacent sub-waveguides 101 to the height of the spacers 102. This prevents the sub-waveguides 101 from shifting when the glue cures.

[0061] Specifically, there are at least two ways to process each optical waveguide stack 10. One way is as follows: Figure 9As shown, the optical waveguide stack 10 is constructed by stacking multiple transparent parallel plates coated with reflective films on both sides. After stacking, adjacent transparent parallel plates are connected by spacers 102 and adhesive layers 103. A single transparent parallel plate is relatively wide, and after stacking, the entire structure forms a block. This block structure is then divided into multiple plate-shaped optical waveguide stacks 10. Figure 9 After three cuts, the middle block structure is processed into four optical waveguide stacks 10, and the large transparent parallel plate is cut into four sub-waveguides 101. Figure 9 In the figure, a single transparent parallel plate coated with a reflective film on both sides before being cut can be considered as one type of substrate 51. To distinguish it from another type of substrate 51, the transparent parallel plate coated with a reflective film on both sides is referred to as a first substrate 511. After the spacers 102 are processed and stacked, the multiple first substrates 511 are filled with glue, cured, and then cut.

[0062] Another way is Figure 10 As shown, the optical waveguide stack 10 requires multiple transparent parallel plates coated with reflective films on both sides to be stacked. After stacking, adjacent transparent parallel plates are connected by spacers 102 and adhesive layers 103. The width of a single transparent parallel plate is consistent with the width of the sub-waveguide 101. After stacking, the entire structure is plate-like, so an optical waveguide stack 10 can be directly processed without segmentation. Figure 10 The transparent parallel plate used is a sub-waveguide 101. Figure 10 In the embodiment, a single transparent parallel plate coated with a reflective film on both sides can be regarded as a substrate 51, which can also be referred to as a first substrate 511. After the spacers 102 are processed and stacked, the multiple first substrates 511 are filled with glue and cured.

[0063] like Figure 3 and Figure 2 As shown, the two processed optical waveguide stacks 10 need to be orthogonal and stacked. The two optical waveguide stacks 10 are separated by a plurality of spacers 102. The gaps between the two optical waveguide stacks 10 are filled with a glue layer 103 formed by curing glue except for the spacers 102. This ensures that the two optical waveguide stacks 10 are firmly connected and parallel to each other. Since the stacking of two optical waveguide stacks 10 requires processing of the spacers 102, a single optical waveguide stack 10 can be regarded as another substrate 51. This substrate 51 also needs to be filled with glue and cured after the spacers 102 are processed and stacked. For the sake of distinction, the optical waveguide stack 10 is referred to as the second substrate 512. Figure 9 and Figure 10 In the process, after the spacers 102 are processed into a plurality of first substrates 511 and the glue is filled and cured, a plurality of second substrates 512 can be cut out or one second substrate 512 can be directly generated.

[0064] In summary, no matter which type of substrate 51 is used, the spacers 102 need to be processed before being filled with glue. In the solution of the present application, at least one layer of spacers 102 is formed on the substrate 51 by embossing. That is to say, when the optical waveguide stack 10 is processed, the spacers 102 can be formed by embossing on one of the transparent parallel flat plates, or the spacers 102 can be formed by embossing on the optical waveguide stack 10 when the two optical waveguide stacks 10 are stacked. By processing the spacers 102 onto the substrate 51 in an embossing manner, the molding efficiency of the spacers 102 is greatly improved, and there is no need to use a robot to place the spacers 102 one by one on the substrate 51.

[0065] Specifically, if Figure 11 As shown, the substrate 51 is formed with spacers 102 by embossing, which includes the following steps:

[0066] S1: Fix the substrate on a fixed base and cover the surface of the substrate with an ink layer 55;

[0067] S2: Covering the side of the substrate covered with the ink layer 55 with an imprint template, with a protrusion provided on the side of the imprint template facing the substrate, the imprint template and the substrate are pressed against each other, so that the area of ​​the ink layer 55 facing the protrusion is squeezed into a concave area, and the concave area of ​​the ink layer 55 forms an ink block 551;

[0068] S3: removing the imprint template from the substrate and solidifying the ink block 551 to form the spacer.

[0069] Here, in step S1, the substrate 51 may be first fixed on the fixed base 52, and then the ink layer 55 may be covered on the substrate 51; alternatively, the ink layer 55 may be first covered on the substrate 51, and then the substrate 51 may be fixed on the fixed base 52. Optionally, the ink layer 55 may be formed on the substrate 51 by spraying, or by other methods, such as brushing.

[0070] Optionally, the action of fixing the substrate 51 on the fixed base 52 can be completed manually, while the remaining imprinting actions are automatically completed by a machine to improve the degree of automation.

[0071] By setting the shape and size of the protrusion 531 on the imprinting template 53, the ink block 551 can be squeezed toward the area without the protrusion 531. The shape of the ink block 551 formed in this way actually forms a complementary relationship with the shape of the protrusion 531. Therefore, the shape of the protrusion 531 roughly determines the shape, size, etc. of the spacer 102.

[0072] By replacing the protrusions 531 on the imprint template 53 with different shapes and sizes, spacers 102 can be formed. The spacing between the protrusions 531 also determines the spacing between the spacers 102. Compared to other processing methods, the use of the protrusions 531 on the imprint template 53 solves many issues, such as the shape and setting parameters of the spacers 102. This not only improves processing efficiency but also achieves high precision in the setting of the spacers 102, reducing the problem of uneven spacing between the spacers 102 caused by factors such as mechanical vibration and fitting errors.

[0073] According to the method for processing the flat lens 1 of the embodiment of the present invention, by embossing the spacers 102 onto the substrate 51, the efficiency of forming the spacers 102 is significantly improved. Furthermore, by adjusting the size of the protrusions 531 on the embossing template 53, parameters such as the height, shape, and spacing of the spacers 102 can be maintained. Because the ink layer 55 is compacted onto the substrate 51 by the embossing template, the ink block 551 is firmly bonded to the substrate 51 after curing. The spacers 102 thus formed are not easily displaced on the substrate 51, and the arrangement of the spacers 102 can be maintained in subsequent steps.

[0074] According to some embodiments of the present invention, the curing method of the ink block 551 is not particularly limited, and those skilled in the art can select it according to actual needs.

[0075] In the solution of the present application, the ink block 551 can be cured naturally, cured by heat, or cured under ultraviolet light. If UV light curing is used, the corresponding choice is UV ink. UV ink is an ink that does not use solvents, dries quickly, has good gloss, bright colors, is water-resistant, solvent-resistant, and has good wear resistance. It can undergo a cross-linking polymerization reaction under UV light (wavelength range of 200-450nm) and instantly cure into a film. UV ink has become a relatively mature ink technology, and its pollution emissions are almost zero.

[0076] According to some specific embodiments of the present invention, in step S3, the ink block 551 forms the spacer 102 through natural curing. The natural curing parameters are: a natural curing time of 10 seconds to 5 minutes, humidity below 50%, avoidance of direct sunlight, and ventilation at a wind speed of 0.1-2 m / s. Therefore, by avoiding direct sunlight during natural curing, the uneven temperature caused by sunlight can be avoided, thereby preventing uneven curing caused by excessive temperature fluctuations. Furthermore, by avoiding direct sunlight and limiting humidity, condensation caused by insufficient temperature and excessive humidity can be avoided.

[0077] According to some specific embodiments of the present invention, in step S3, the ink block 551 is cured by heating. Compared with natural curing, the heating temperature during the curing can be selected between 19-150° C. This can shorten the curing time.

[0078] According to other specific embodiments of the present invention, in step S3, the ink block 551 is cured under ultraviolet light with a wavelength of 200-450 nm. The curing conditions are: a curing temperature of 19°C-25°C, a humidity of less than 50%, and ventilation with a wind speed ranging from 0.1-2 m / s. This prevents environmental factors from affecting the curing process of the spacer 102, ensuring that the spacer 102 has a satisfactory height uniformity.

[0079] Specifically, when the ink block 551 is cured under ultraviolet light in step S3, the wavelength of the ultraviolet light is 365nm or 395nm, or the ultraviolet light is a mixed light composed of 365nm and 395nm, and the irradiance of the ultraviolet light is 20-1500mW / cm 2 The total energy of the ultraviolet light is required to be 2000-5000 mJ / cm2. Thus, the ink can be quickly hardened under the ultraviolet light to form a solid spacer 102.

[0080] In some embodiments, when the imprint template 53 and the substrate 51 are pressed against each other in step S2 , the pressure is 0.3-11 bar, the ambient temperature is 19-25° C., and the ambient humidity is less than 50%, thereby avoiding excessive temperature fluctuations or excessive humidity affecting the curing stability.

[0081] Specifically, during the embossing process, the pressure can be adjusted.

[0082] In some embodiments, the ambient temperature in step S2 is maintained at 19-25° C., which can prevent excessive fluctuations in ambient temperature from affecting the molding stability of the spacer 102 .

[0083] According to some embodiments of the present invention, the specific type of ink material is not particularly limited, and those skilled in the art can select it according to actual needs. According to some specific embodiments of the present invention, the ink layer 55 is a light-curing adhesive or a heat-curing adhesive.

[0084] Specifically, the ink layer is one or more of epoxy resin, acrylic resin, chlorinated acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyurethane and polyamide resin, thereby ensuring the hardness, bonding strength, water resistance and the like of the spacer 102 .

[0085] It should be noted that to ensure the processing quality and imaging effect of flat lens 1, the inventors' team conducted in-depth research on every production step of flat lens 1. The imaging quality of flat lens 1 is related to the quality of the transparent parallel plates themselves, the parallelism of the transparent parallel plates when stacked to form optical waveguide stack 10, and the parallelism of the two optical waveguide stacks 10.

[0086] Here, transparent parallel plates (first substrates 511) are stacked and glued together to form an optical waveguide stack 10. Two optical waveguide stacks 10 (second substrates 512) are also glued together to form a flat lens 1. The parallelism of the two adjacent first substrates 511 and the two second substrates 512 is critically influenced by the uniform thickness of the adhesive layer 103 formed after the glue cures. However, the adhesive layer 103 generates stress during curing and shrinkage, making it challenging to maintain consistent shrinkage stress across the adhesive layer 103.

[0087] The present invention addresses the aforementioned technical issues by utilizing spacers 102 to ensure uniform thickness of adhesive layer 103. Spacers 102 are fabricated directly onto substrate 51, and the shape, height, and spacing of spacers 102 are guaranteed by the protrusions on the embossing template.

[0088] In order to ensure the supporting effect of the spacer 102 , in this application, the viscosity of the ink before curing is limited to 10,000-50,000 cps, and the Shore hardness of the spacer 102 after curing is limited to 70A-90D.

[0089] It is understood that if the viscosity of the ink used to make the spacer 102 is not appropriate, there will be many adverse consequences.

[0090] If the ink viscosity is too low, the ink is highly fluid, making molding difficult. If the height / area ratio is too large, the density of spacers that can be produced will decrease, and the support of the spacers 102 will be reduced. When bonding substrates 51 to substrates 51, glue will need to be filled between the substrates 51. If the support of the spacers 102 is insufficient, the stress generated by the curing shrinkage of the glue can easily cause deformation of the substrates 51, ultimately resulting in distorted imaging of the flat lens 1.

[0091] Moreover, if the height / area value is too large, the area occupied by the ink on the entire substrate is too high, and the area where the glue can adhere is reduced after the subsequent glue filling, resulting in weak adhesion and the substrate 51 being broken.

[0092] On the contrary, if the ink viscosity is too high, it is difficult to accurately control the amount of ink sprayed each time, resulting in uneven distribution of the spacers 102 and poor support of the spacers 102. This can eventually cause deformation of the substrate 51 and distorted imaging of the manufactured flat lens 1.

[0093] Based on the above reasons, after analysis and repeated experiments, the inventors' team set the ink viscosity to 10,000-50,000 cps before curing, making it easier to form after curing. Furthermore, the spacers 102 can be arranged at an appropriate density, and after curing, the Shore hardness of the spacers 102 can reach 70A-90D, ensuring sufficient support. This spacer 102 is less likely to collapse or deform under stress, ensuring sufficient adhesive adhesion and a strong bond, preventing the substrate 51 from breaking.

[0094] In addition, the Shore hardness of the spacer 102 is set to 70A-90D. If the hardness is lower than 70A, the spacer 102 is easily deformed and insufficient to play a supporting role. If the hardness is higher than 90D, the hardness of the spacer 102 is too high, which may cause deformation or damage to the surface layer of the substrate 51.

[0095] The following uses multiple embodiments in which spacers 102 are formed on the first substrate 511 and the second substrate 512 by embossing and then filled and cured with glue to bond them together, and compares the requirements for setting the spacers 102 in each embodiment and the possible impact of not meeting the requirements, as shown in Table 1 below.

[0096] Table 1

[0097]

[0098]

[0099] In the above embodiments, the filling glue parameters and their effects are shown in Table 2 below.

[0100] Table 2

[0101]

[0102] In some embodiments, the height error of the spacers 102 is ≤10%. Limiting the height error of the spacers 102 to 10% ensures that the spacing between the substrates 51 at different locations does not differ by more than 10%. This prevents some spacers 102 from being too short and unable to form effective support between the two substrates 51. This also prevents these spacers 102 from shifting during glue pouring.

[0103] In some embodiments, as Figure 11 As shown, the fixed base 52 is provided with a plurality of latches 521, which are latched onto the substrate 51. This allows for convenient fastening of the substrate 51 to the fixed base 52, making assembly and disassembly of the substrate 51 easy, and accelerating the processing of the spacers 102 on the substrate 51. Of course, the solution of the present application is not limited to this. In other embodiments, when the substrate 51 is fixed to the fixed base 52, clamping blocks may be used to clamp at least two horizontal sides of the substrate 51.

[0104] Optionally, the substrate 51 is adsorbed on the fixed base 52 by negative pressure to ensure that the substrate 51 is completely fixed relative to the fixed base 52 during the imprinting process.

[0105] In some solutions, the ink block 551 is solidified before the imprint template 53 is pulled away. In some solutions, the ink block 551 is solidified after being pulled away from the imprint template 53. There is no limitation here.

[0106] In some alternative embodiments, the protrusions 531 are formed in a mesh shape, with the outer contours of the protrusions 531 completely covering the ink layer 55. This way, when the ink layer 55 is squeezed by the protrusions 531 as a whole, it is compressed into a grid pattern, with each individual grid forming an ink block 551, which ultimately solidifies to form separated spacers 102. This prevents the spacers 102 from forming a single row when glue is subsequently injected into the substrate 51, facilitating the glue from filling the gaps.

[0107] In some optional embodiments, the imprint template 53 is cleaned after multiple uses to prevent residual ink from solidifying and occupying the corner areas of the protrusions 531.

[0108] In some solutions, the imprinting template 53 is detachably arranged on the fixed base 52. Here, the imprinting template 53 can be removed and cleaned, or the entire processing device can be directly cleaned.

[0109] In the solution of the present application, the material of the imprint template 53 is optional. According to the type of the substrate 51, a material with good hardness and good adhesion to the substrate 51 can be selected, such as resin.

[0110] In some embodiments, after at least two substrates 51 are stacked via spacers 102, a glue pool is connected, and the glue in the glue pool is filled between adjacent substrates 51 by pressure difference or gravity. In this way, during glue pouring, the position of the spacers 102 and the two side substrates 51 is relatively fixed, and the spacers 102 are not easily displaced during the glue pouring process, and the spacers 102 can still maintain an appropriate distance after glue pouring.

[0111] Specifically, after the spacers 102 are embossed on the substrate 51, they are stacked by a robotic arm, and then the stacked structure is clamped and placed in a glue pool. After being placed in the glue pool, a vacuum can be drawn to form a negative pressure, so that the glue is injected into the stacked gaps. When the temperature reaches a certain level, the glue produces a thermal curing reaction to achieve gluing. In some solutions, the relative position of the glue pool and the stacked structure has changed, and gravity can be used to automatically flow the glue into the stacked gaps. In other solutions, although the glue filling is also driven by pressure difference, the glue pool can be pressurized to press the glue into the stacked gaps.

[0112] Since the spacers 102 have comparable hardness and adhesion, and are not subjected to gravity lamination to prevent displacement during lamination, the spacers 102 will not shift during lamination. After curing, the ink adheres to the surface of the substrate 51, with sufficient adhesion to prevent the spacers 102 from shifting during lamination.

[0113] In the description of this specification, the reference terms "embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least some embodiments or examples of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0114] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for processing a flat lens, characterized in that: The flat lens is formed by stacking two optical waveguide layers along the Z direction, each of the optical waveguide layers being composed of a single row of multiple-row sub-waveguides with a rectangular cross-section. The two optical waveguide layers include a first optical waveguide layer and a second optical waveguide layer. The sub-waveguides of the first optical waveguide layer extend along the X direction and form multiple rows along the Y direction, and the sub-waveguides of the second optical waveguide layer extend along the Y direction and form multiple rows along the X direction. The X direction, the Y direction, and the Z direction are perpendicular to each other. Each optical waveguide stack is formed by stacking transparent parallel plates coated with reflective films on both sides, and the transparent parallel plates are the first substrate; when the two optical waveguide stacks are stacked to form the flat lens, the optical waveguide stack is the second substrate; the first substrate and the second substrate are both substrates; A plurality of spacers are provided between two adjacent substrates when they are stacked, and at least one layer of the spacers is formed on the substrates by embossing; Forming the spacers on the substrate by embossing comprises the following steps: S1: fixing the substrate on a fixed base and covering the surface of the substrate with an ink layer; S2: Covering the side of the substrate covered with the ink layer with an imprint template, wherein the imprint template is provided with a protrusion on the side facing the substrate, and pressing the imprint template and the substrate against each other, so that the area of ​​the ink layer facing the protrusion is squeezed into a concave area, and the concave area of ​​the ink layer forms an ink block; S3: removing the imprint template from the substrate and solidifying the ink block to form the spacer; In step S3, the ink block is cured under ultraviolet light, wherein the wavelength of the ultraviolet light is 200-450 nm, and the curing conditions are: a curing environment temperature of 19° C. to 25° C., a curing environment humidity of less than 50%, and ventilation with a wind speed ranging from 0.1 m / s to 2 m / s to remove volatile gases generated by the curing of the ink; The viscosity of the ink before curing is 10,000-50,000 cps, and the Shore hardness of the spacer after curing is 70A-90D.

2. The method according to claim 1, characterized in that When the ink block is cured under ultraviolet light in step S3, the wavelength of the ultraviolet light is 365nm or 395nm, or the ultraviolet light is a mixed light composed of 365nm and 395nm, and the irradiance of the ultraviolet light is 20mW / cm 2 -1500mW / cm 2 The total energy of the ultraviolet light is required to be 2000-5000mJ / cm 2 .

3. The method according to claim 1, characterized in that The ink layer is a light-curing adhesive or a heat-curing adhesive.

4. The method according to claim 1, wherein The ink layer is one or more of epoxy resin, acrylic resin, chlorinated acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyurethane and polyamide resin.

5. The method according to claim 1, wherein The ambient temperature in step S2 was maintained at 19-25°C.

6. The method according to claim 1, characterized in that The spacers between adjacent first substrates use ink with a viscosity of 10,000-30,000 cps. After curing, the Shore hardness of the spacers is 25D-40D. The height of the spacers is 10-100 μm, and the distance between adjacent spacers is 2-3 mm.

7. The method according to claim 1, characterized in that The spacers between adjacent first substrates use ink with a viscosity of 10,000-30,000 cps. After curing, the Shore hardness of the spacers is 70A-25D. The height of the spacers is 10-100 μm, and the distance between adjacent spacers is 0.5-1 mm.

8. The method according to claim 1, characterized in that The spacers between adjacent second substrates use ink with a viscosity of 10,000-50,000 cps. After curing, the Shore hardness of the spacers is 30D-90D. The height of the spacers is 50-500 μm, and the distance between adjacent spacers is 10-50 mm.

9. The method according to claim 1, characterized in that The fixing base is provided with a plurality of fasteners, and the plurality of fasteners are fastened to the base plate.

10. The method according to claim 1, characterized in that After at least two substrates are stacked via the spacers, a glue pool is connected, and the glue in the glue pool is filled between adjacent substrates by pressure difference or gravity.

11. The method according to any one of claims 1 to 10, characterized in that The protrusions are formed in a mesh shape, and the outer contours of the protrusions completely cover the ink layer.

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