CN113448014A - Relief type waveguide structure and manufacturing method thereof - Google Patents
Relief type waveguide structure and manufacturing method thereof Download PDFInfo
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- CN113448014A CN113448014A CN202010220340.0A CN202010220340A CN113448014A CN 113448014 A CN113448014 A CN 113448014A CN 202010220340 A CN202010220340 A CN 202010220340A CN 113448014 A CN113448014 A CN 113448014A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/124—Geodesic lenses or integrated gratings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
- G02B6/132—Integrated optical circuits characterised by the manufacturing method by deposition of thin films
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
- G02B6/136—Integrated optical circuits characterised by the manufacturing method by etching
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Abstract
The invention discloses a relief type waveguide structure and a manufacturing method thereof, wherein the relief type waveguide structure comprises the following steps: providing a substrate serving as a waveguide carrier of the relief-type waveguide structure; forming a patterned layer on the substrate, the patterned layer having a refractive index less than a refractive index of the substrate; forming a pattern of nanostructures through the pattern-forming layer on the pattern-forming layer; filling the nanostructure pattern to form an optical structure material layer, wherein the refractive index of the optical structure material layer is higher than that of the pattern forming layer, and the optical structure material layer is in direct contact with the substrate layer; and removing the pattern forming layer. The relief type waveguide structure and the manufacturing method thereof provided by the invention really solve the problem that the high refractive index substrate in the prior art is difficult to etch, develop a new way to solve the manufacturing difficulty and promote the development of the display technology.
Description
Technical Field
The invention relates to the technical field of display, in particular to a relief type waveguide structure and a manufacturing method thereof.
Background
Science and technology changes life, and life is heavily experienced, and augmented reality display technology takes place in order to obtain better visual experience. The augmented reality technology is a new technology for seamlessly integrating real world information and virtual world information, integrates visual feedback information of the real world and the virtual world, and mutually supplements and superposes information of two different sources to form a brand-new visual feast.
In order to experience the excellent visual perception, people generally use a head-mounted display to fulfill the requirement, and most of the current mainstream near-eye augmented reality display devices adopt an optical waveguide principle. For example, microsoft Hololens holographic glasses couple an image On Liquid Crystal Silicon (also called Liquid Crystal On Silicon or single Crystal Silicon reflective Liquid Crystal, english: Liquid Crystal On Silicon; abbreviated as LCOS) to an optical waveguide through three holographic gratings, respectively transmit the image through three optical waveguides, finally couple and output the image through corresponding holographic gratings right in front of human eyes, project the image to the human eyes, and realize color projection in a multilayer optical waveguide manner.
At present, the application of optical waveguides in the augmented reality technology is more and more intensive, researchers have proposed methods such as imprinting, etching, and exposing in order to manufacture the waveguide surface relief nano structure, however, in the actual manufacturing process, such as the nano imprinting method, although the waveguide lens can be manufactured in large batch, the refractive index of the current imprinting glue is limited to not match with the waveguide substrate, so that the display quality is affected, and the display resolution is reduced.
As shown in fig. 1 for a schematic ray diagram of the case where the refractive index of the nanostructure does not match the refractive index of the waveguide substrate: in the figure, the nanostructure 12 made of the material with the low refractive index is arranged on the substrate 11 with the high refractive index, the incident light a is incident at a certain incident angle, and the diffraction light trend is the non-standard light B because the refractive indexes of the substrate 11 and the nanostructure 12 are different, but if the refractive indexes of the substrate 11 and the nanostructure 12 are the same, the diffraction light trend is the standard light C.
Therefore, the mismatch of the refractive indexes of the substrate and the nano material can cause the actual diffraction light to move towards other than the standard light, so that the diffraction angle is greatly deviated, the capability of the waveguide substrate for conducting light through the nano structure is deviated, and the problems of image display haziness, light crosstalk and the like are caused by the deviation of the light.
Continuing with FIG. 2, a view-field transmission diagram of an optical waveguide is shown: light 1(P) and light 2(Q) are incident on the surface of the waveguide lens at an incident angle θ, α and β are diffraction angles of light 1 and light 2, respectively, n is refractive index of the waveguide and the nanostructure, d is thickness of the waveguide lens, according to the light diffraction formula 1 and formula 2:
d*1*sinθ-d*n*sinα＝-λ①
d*1*sinθ+d*n*sinβ＝λ②
taking into account the total reflection of the diffraction angle in the waveguide, equation 3 is obtained by calculation:
n＞2sinθ+1③
as can be seen from equation 3, the field angle is closely related to the refractive index, i.e. if the refractive index of the nanostructure is not matched to the waveguide, or is much smaller than the refractive index of the waveguide, the achievable field angle is limited.
From the above, in the display scheme of realizing the optical transmission type augmented reality by using the planar optical waveguide principle, the mismatch between the refractive index of the nanostructure and the refractive index of the waveguide substrate can cause many display problems.
Therefore, it is necessary to provide a new technical solution to solve the above problems, and to promote the development of the planar optical waveguide augmented reality display technology.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides a manufacturing method of a relief type waveguide structure, which adopts the following technical scheme:
a method of fabricating a relief-type waveguide structure, comprising:
providing a substrate serving as a waveguide carrier of the relief-type waveguide structure;
further, forming a patterned layer on the substrate, wherein the refractive index of the patterned layer is smaller than that of the substrate;
further, forming a pattern of nanostructures through the patterned layer on the patterned layer;
further, filling the nanostructure pattern to form an optical structure material layer, wherein the refractive index of the optical structure material layer is higher than that of the pattern forming layer, and the optical structure material layer is in direct contact with the substrate layer;
further, the pattern forming layer is removed.
Further, it still includes:
continuously forming a planarization dielectric layer on the nanostructure pattern and the pattern forming layer filled with the optical structure material layer;
further, removing excessive materials from the top of the planarization medium layer downwards until the pattern forming layer and the optical structure material layer are exposed, wherein the height of the optical structure material layer is consistent with the target height.
Further, the planarization dielectric layer covers the surface of the nanostructure pattern and the pattern forming layer in a spin coating, spray coating, blade coating or brush coating mode.
Further, under the depth control of an atomic force microscope, material removal is carried out on the planarization dielectric layer in a reactive ion beam bevel etching or chemical mechanical planarization mode, so that the height of the pattern forming layer is consistent with that of the optical structure material layer, and the surface of the pattern forming layer is not covered by the optical structure material layer.
Further, the filling height of the optical structure material layer filled in the nanostructure pattern is not more than two thirds of the thickness of the pattern forming layer.
Further, when the filling height of the optical structure material layer is more than two thirds of the thickness of the pattern forming layer, a planarization medium layer is coated on the surfaces of the nanometer structure pattern and the pattern forming layer,
further, the depth-diameter ratio of the micro-nano graph of the optical structure material layer is more than 2.
Further, the substrate is made of a transparent material, and the refractive index of the substrate is greater than 1.6;
further, the material of the pattern forming layer is low-refractive index photoresist, and the refractive index of the pattern forming layer is not more than 1.6;
furthermore, the material of the optical structure material layer is one or more of titanium dioxide, magnesium fluoride and aluminum oxide, and the refractive index of the optical structure material layer is greater than 1.6;
furthermore, the material of the planarization dielectric layer is flowable glass or flowable oxide.
Further, the flowable glass comprises a polymethylsiloxane and a silicate group;
the flowable oxide includes hydrogen silsesquioxane.
Further, the pattern forming layer uniformly covers the surface of the substrate by spin coating, spray coating and blade coating.
Further, the nanostructure pattern is prepared on the pattern forming layer by means of photolithography and/or exposure.
Further, the optical structure material layer is uniformly covered on the nanostructure pattern through evaporation, deposition and sputtering.
Further, the pattern forming layer is removed by a solution method in cooperation with a microwave plasma machine.
The invention also provides a relief type waveguide structure, which comprises an optical waveguide element and a plurality of grating units formed on the surface of the optical waveguide element, wherein a nano-structure pattern is arranged among the grating units, the bottom of the nano-structure pattern is connected with the surface of the optical waveguide element,
preferably, the grating unit is a cylinder structure, and the height-diameter ratio of the grating unit is not less than 2.
Preferably, the end face of the grating unit is circular or polygonal in shape;
preferably, when the end face of the grating unit is circular in shape, the height-diameter ratio of the grating unit is the ratio of the height of the grating unit to the diameter of the end face;
preferably, when the end face of the grating unit is polygonal in shape, the height-diameter ratio of the grating unit is the ratio of the height of the grating unit to the longest diagonal length of the end face.
Preferably, the material of the grating unit is one or more of titanium dioxide, magnesium fluoride and aluminum oxide;
preferably, the heights of the plurality of grating units are consistent;
preferably, the difference of the refractive indexes of the grating unit and the optical waveguide element ranges from 0 to 0.5.
In the prior art, the surface nano structure is generally formed by a photoresist material, and a large technical difficulty exists if a high-refractive-index substrate is etched.
Compared with the prior art, the invention has one or more of the following beneficial effects:
1. according to the invention, the nanostructure pattern with high refractive index is formed on the substrate with high refractive index by an additive manufacturing method, the nanostructure pattern is formed on the surface of the pattern forming layer in a photoetching and/or exposure mode, and the nanostructure pattern is filled by the optical structure material layer with high refractive index, wherein the used photoetching or exposure preparation process is mature, the feasibility of the scheme is high, and the problem of high etching difficulty of the substrate with high refractive index in the prior art is solved;
2. the invention utilizes the optical structure material layer to fill the nanometer structure pattern, if the precise height-diameter ratio is not required, the waveguide structure can be obtained by removing the pattern forming layer, but if the precise height-diameter ratio is required, the invention continuously covers the planarization medium layer on the optical structure material layer, then removes the top of the optical structure material layer by the mechanical planarization nanometer structure combined with the ion beam etching or the chemical grinding method, and utilizes the atomic force microscope to carry out depth control, thus obtaining the grating structure with precise height-diameter ratio;
3. the waveguide substrate manufactured by the prior art is not matched with the refractive index of the nano structure, so that the problems of hazy background light or light crosstalk and the like exist, and the image display resolution is not high;
4. the field angle of the display can be reduced due to the fact that the refractive index of the waveguide substrate manufactured by the prior art is not matched with the refractive index of the nano structure, the field angle which can be achieved can be enlarged due to the fact that the substrate with the high refractive index is matched with the grating unit with the high refractive index, normal conduction of light in the field range is guaranteed, and the capability of augmented reality display is stronger compared with that of the prior art.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic diagram of light rays in the case where the refractive index of the nanostructure is mismatched to the refractive index of the waveguide substrate, where A is incident light, B is non-standard light, and C is standard light;
FIG. 2 is a schematic view of the field propagation of a waveguide structure, where P is ray 1 and Q is ray 2;
FIG. 3 is a schematic view of step 130 of a method of manufacturing a waveguide structure according to embodiment 1 of the present invention;
FIG. 4 is a schematic view of step 140 of the method for manufacturing a waveguide structure according to embodiment 1 of the present invention;
FIG. 5 is a schematic view of step 150 of the waveguide structure fabrication method according to embodiment 1 of the present invention;
fig. 6 is a schematic flow chart of a method for manufacturing a waveguide structure in embodiment 1 of the present invention;
FIG. 7 is a schematic view of step 240 of a method of manufacturing a waveguide structure according to embodiment 2 of the present invention;
FIG. 8 is a schematic view of step 250 of a method for manufacturing a waveguide structure according to embodiment 2 of the present invention;
FIG. 9 is a schematic view of step 260 of the waveguide structure fabrication method according to embodiment 2 of the present invention;
FIG. 10 is a schematic diagram of the overall structure of the embossed waveguide structure of the present invention;
fig. 11 is a schematic flow chart of a method for manufacturing a waveguide structure in embodiment 2 of the present invention.
Wherein, 1-substrate, 2-pattern forming layer, 3-nano structure pattern, 4-optical structure material layer; 5-flattening the dielectric layer; 6-optical waveguide elements, 7-grating units,
11-high refractive index substrate; 12-nanostructures.
Detailed Description
The technical solutions of the embodiments of the present invention will be described below in detail by referring to the drawings of the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example (b):
the gist of the present invention will be further explained below with reference to the accompanying drawings and examples.
Example 1:
referring to fig. 3-6, the present invention provides a method for manufacturing a relief-type waveguide structure, including the following steps:
referring to fig. 6: step 110, providing a high refractive index substrate 1, wherein the substrate 1 is used as a waveguide carrier of a relief type waveguide structure.
In one embodiment, the refractive index of the high refractive index substrate 1 may be greater than 1.6, and the substrate 1 is made of a visible light high transparent material.
In one embodiment, the refractive index of the pattern forming layer 2 is not greater than 1.6, the material of the pattern forming layer 2 may be low refractive index resist, and the like, and the pattern forming layer 2 may cover the surface of the substrate 1 by spin coating, spray coating, or blade coating.
In step 130, a nanostructure pattern 3 is formed on the pattern forming layer 2.
In one embodiment, a pattern topography may be obtained on the patterned layer 2 by photolithography, exposure, etc., resulting in a pattern of nanostructures 3, see fig. 3.
In step 140, a common filling is performed on the nanostructure pattern layer, i.e. a layer of optical structure material 4 is formed in the nanostructure pattern 3, see fig. 4.
In an embodiment, the refractive index of the optical structure material layer 4 is greater than 1.6, and may be referred to as a high refractive index material, the material may be one or more of titanium dioxide, magnesium fluoride and aluminum oxide, the optical structure material layer 4 may cover the surface of the nanostructure pattern 3 by evaporation, deposition and sputtering, so as to fill the nanostructure pattern 3, the optical structure material layer 4 may also cover the surface of the pattern forming layer 2 during evaporation, deposition and sputtering, and the filling height of the optical structure material layer 4 filled in the nanostructure pattern 3 is not greater than two thirds of the thickness of the pattern forming layer 2.
In one embodiment, the patterned layer 2 and the layer of optical structure material 4 overlying the patterned layer 2 during evaporation, deposition and sputtering may be removed by a solution process in conjunction with a microwave plasma.
With continued reference to fig. 10, the embossed waveguide structure manufactured by the above-mentioned manufacturing method includes an optical waveguide element 6 and a plurality of grating units 7 formed on the surface of the optical waveguide element 6, a nanostructure pattern 3 is formed between the plurality of grating units 7, the bottom of the nanostructure pattern 3 is connected to the surface of the optical waveguide element 6,
further, the grating unit 7 is a cylindrical structure, and the height-diameter ratio of the grating unit 7 is not less than 2.
Further, the end face of the grating unit 7 is circular or polygonal;
further, when the end surface of the grating unit 7 is circular, the height-diameter ratio of the grating unit 7 is the ratio of the height of the grating unit 7 to the end surface diameter;
further, when the end surface of the grating unit 7 is polygonal, the aspect ratio of the grating unit 7 is the ratio of the height of the grating unit 7 to the longest diagonal length of the end surface.
Further, the material of the grating unit 7 is one or more of titanium dioxide, magnesium fluoride and aluminum oxide;
further, the heights of the grating units 7 are consistent;
further, the difference range of the refractive indexes of the grating unit 7 and the optical waveguide element 6 is 0-0.5, and when the difference range of the refractive indexes of the grating unit 7 and the optical waveguide element 6 approaches 0, the light in the waveguide structure approaches to the designed standard light, so that the image display is clearer, and the field angle is wider.
The manufacturing method described in this embodiment is suitable for manufacturing a waveguide structure in which the height-diameter ratio of the grating unit 7 is greater than 2, and the filling height of the optical structure material layer 4 filled in the nanostructure pattern 3 is not greater than two-thirds of the thickness of the pattern forming layer 2 in the manufacturing process.
One of the key points of the invention is to realize that the refractive indexes of the waveguide surface relief nanostructure and the waveguide substrate are almost matched through the design and integration of the process flow and the reasonable optimization of the process link, thereby improving the display resolution; the second important point is that the nano pattern is formed by material increase and then the nano pattern is filled with the high-refraction nano structure, so that the matching degree of the refractive indexes of the substrate and the nano structure is improved as much as possible.
Example 2:
referring to fig. 7-11, the present invention further provides another method for manufacturing a relief waveguide structure, which includes the following steps:
referring to fig. 11: step 210, providing a high refractive index substrate 1, wherein the substrate 1 is used as a waveguide carrier of a relief type waveguide structure.
In one embodiment, the refractive index of the high refractive index substrate 1 may be greater than 1.6, and the substrate 1 is made of a visible light high transparent material.
In one embodiment, a low refractive index material layer is formed on a high refractive index material layer, i.e., the substrate 1, the material of the pattern forming layer 2 may be low refractive index resist, etc., and the pattern forming layer 2 may cover the surface of the substrate 1 by spin coating, spray coating, or blade coating, etc.
In one embodiment, the pattern topography may be obtained on the patterned layer 2 by photolithography, exposure, etc., resulting in a pattern of nanostructures 3.
In step 240, the nanostructure pattern layer is filled in a common way, i.e. a layer of optical structure material 4 is formed in the nanostructure pattern 3, see fig. 7.
In an embodiment, the refractive index of the optical structure material layer 4 is greater than 1.6, and may be referred to as a high refractive index material, the material may be one or more of titanium dioxide, magnesium fluoride and aluminum oxide, the optical structure material layer 4 may cover the surface of the nanostructure pattern 3 by evaporation, deposition, sputtering, and the like, so as to fill the nanostructure pattern 3, and the optical structure material layer 4 may also cover the surface of the pattern forming layer 2 during evaporation, deposition, and sputtering.
In step 250, a planarization dielectric layer 5 is formed on the optical structure material layer 4, and planarization is performed on the filled nanostructure layer, as shown in fig. 8.
In one embodiment, the planarization medium layer 5 is a planarization medium required for planarization, so the material of the planarization medium layer 5 can be a flowable glass or a flowable oxide, and the flowable glass can be a flowable glass such as polymethylsiloxane, silicate, etc.; the flowable oxide may be hydrogen silsesquioxane or the like, in which case, the filling height of the optical structure material layer 4 filled in the nanostructure pattern 3 is greater than two thirds of the thickness of the pattern formation layer 2;
the planarization treatment is to remove the redundant material from the top of the planarization medium layer 5 downwards until the pattern forming layer 2 and the optical structure material layer 4 are exposed, and the height of the optical structure material layer 4 is consistent with the target height;
the planarization medium layer 5 is covered on the optical structure material layer 4 by spin coating, spray coating, blade coating or brush coating.
In step 260, top plane removal is performed, and the top plane is removed to the required height synchronously, as shown in fig. 9.
In one embodiment, the top surface of the uppermost planarization dielectric layer 5 is removed by reactive ion beam bevel etching or chemical mechanical planarization, and the depth control is performed in cooperation with an atomic force microscope, so that the height of the optical structure material layer 4 is consistent with the target height.
In step 270, the remaining low refractive index nanostructures are removed, i.e. the pattern forming layer 2 is removed.
In one embodiment, the pattern forming layer 2 may be removed by a solution method, a microwave plasma machine, or the like.
With continued reference to fig. 10, the embossed waveguide structure manufactured by the above-mentioned manufacturing method includes an optical waveguide element 6 and a plurality of grating units 7 formed on the surface of the optical waveguide element 6, a nanostructure pattern 3 is formed between the plurality of grating units 7, the bottom of the nanostructure pattern 3 is connected to the surface of the optical waveguide element 6,
further, the grating unit 7 is a cylindrical structure, and the height-diameter ratio of the grating unit 7 is not less than 2.
Further, the end face of the grating unit 7 is circular or polygonal;
further, when the end surface of the grating unit 7 is circular, the height-diameter ratio of the grating unit 7 is the ratio of the height of the grating unit 7 to the end surface diameter;
further, when the end surface of the grating unit 7 is polygonal, the aspect ratio of the grating unit 7 is the ratio of the height of the grating unit 7 to the longest diagonal length of the end surface.
Further, the material of the grating unit 7 is one or more of titanium dioxide, magnesium fluoride and aluminum oxide;
further, the heights of the grating units 7 are consistent;
further, the difference range of the refractive indexes of the grating unit 7 and the optical waveguide element 6 is 0-0.5, and when the difference range of the refractive indexes of the grating unit 7 and the optical waveguide element 6 approaches 0, the light in the waveguide structure approaches to the designed standard light, so that the image display is clearer, and the field angle is wider.
The manufacturing method described in this embodiment is suitable for manufacturing a waveguide structure in which the height-diameter ratio of the grating unit 7 is greater than 2, and the filling height of the optical structure material layer 4 filled in the nanostructure pattern 3 is greater than two thirds of the thickness of the pattern forming layer 2 in the manufacturing process.
One of the key points of the invention is to realize that the refractive indexes of the waveguide surface relief nanostructure and the waveguide substrate are almost matched through the design and integration of the process flow and the reasonable optimization of the process link, thereby improving the display resolution; the second important point is that the nano pattern is formed by material increase and then the nano pattern is filled with the high-refraction nano structure, so that the matching degree of the refractive indexes of the substrate and the nano structure is improved as much as possible.
With reference to embodiments 1 and 2, the invention forms a nanostructure with high refractive index on a substrate with high refractive index by an additive manufacturing method, the nanostructure pattern is formed on the surface of the pattern forming layer by means of photolithography and/or exposure, and the nanostructure pattern is filled with a light structure forming layer with high refractive index.
Furthermore, the invention uses the optical structure material layer to fill the nano-structure pattern, if the precise height-diameter ratio is not required, the waveguide structure can be obtained by removing the pattern forming layer, but if the precise height-diameter ratio is required, the invention continuously covers the planarization dielectric layer on the optical structure material layer, then removes the top of the optical structure material layer by combining the mechanical planarization nano-structure with the ion beam etching or the chemical grinding method, and uses the atomic force microscope to carry out the depth control, thus obtaining the grating structure with the precise height-diameter ratio.
According to the invention, by using the scheme that the substrate with high refractive index is matched with the nano structure with high refractive index, the display problems of image haziness, light crosstalk and the like caused by refractive index mismatching can be weakened, and the display quality is further improved.
The invention can enlarge the achievable field angle by utilizing the substrate with high refractive index to match the nano structure with high refractive index, ensures the normal conduction of light rays in the field range, and has stronger capability of augmented reality display compared with the prior art.
In conclusion, the relief type waveguide structure and the manufacturing method thereof provided by the invention really solve the problem of high difficulty in etching the high-refractive-index substrate in the prior art, solve the manufacturing difficulty in a new way and promote the development of the display technology.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.
While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.
Claims (15)
1. A method for fabricating a relief-type waveguide structure, comprising:
providing a substrate (1), wherein the substrate (1) is used as a waveguide carrier of a relief type waveguide structure;
forming a patterned layer (2) on the substrate (1), the patterned layer (2) having a refractive index less than a refractive index of the substrate (1);
forming a pattern of nanostructures (3) on the patterned layer (2) throughout the patterned layer (2);
filling the nanostructure pattern (3) to form an optical structure material layer (4), wherein the refractive index of the optical structure material layer (4) is higher than that of the pattern forming layer (2), and the optical structure material layer (4) is in direct contact with the substrate (1) layer;
removing the pattern forming layer (2).
2. The method of manufacturing according to claim 1, further comprising:
continuing to form a planarization dielectric layer (5) on the nanostructure pattern (3) filled with the optical structure material layer (4) and the pattern forming layer (2);
and removing redundant materials from the top of the planarization medium layer (5) downwards until the pattern forming layer (2) and the optical structure material layer (4) are exposed, wherein the height of the optical structure material layer (4) is consistent with the target height.
3. The method according to claim 2, wherein the planarization dielectric layer (5) is coated on the surface of the nanostructure pattern (3) and the patterning layer (2) by spin coating, spray coating, blade coating or brush coating.
4. The manufacturing method according to claim 2, characterized in that under the depth control of an atomic force microscope, the planarization dielectric layer (5) is subjected to material removal by means of reactive ion beam bevel etching or chemical mechanical planarization, so that the height of the patterned layer (2) is consistent with the height of the optical structure material layer (4), and the surface of the patterned layer (2) is not covered by the optical structure material layer (4).
5. A method of manufacturing according to claim 1, wherein the filling height of the layer of optical structure material (4) filled within the pattern of nanostructures (3) is not more than two thirds of the thickness of the patterned layer (2).
6. A method of manufacturing according to claim 2, wherein a planarization medium layer (5) is applied to the surface of the nanostructure pattern (3) and the patterned layer (2) when the filling height of the optical structure material layer (4) is greater than two-thirds of the thickness of the patterned layer (2),
the depth-diameter ratio of the micro-nano graph of the optical structure material layer (4) is more than 2.
7. The method of manufacturing according to claim 1,
the substrate (1) is made of transparent materials, and the refractive index of the substrate (1) is larger than 1.6;
the material of the pattern forming layer (2) is low-refractive index photoresist, and the refractive index of the pattern forming layer (2) is not more than 1.6;
the optical structure material layer (4) is made of one or more of titanium dioxide, magnesium fluoride and aluminum oxide, and the refractive index of the optical structure material layer (4) is greater than 1.6;
the material of the planarization dielectric layer (5) is flowable glass or flowable oxide.
8. The method of claim 7, wherein the flowable glass comprises a polymethylsiloxane and a silicate group;
the flowable oxide includes hydrogen silsesquioxane.
9. The method according to claim 1, wherein the patterned layer (2) is uniformly coated on the surface of the substrate (1) by spin coating, spray coating and blade coating.
10. A method of production according to claim 1, characterised in that the pattern of nanostructures (4) is produced on the patterned layer (2) by means of photolithography and/or exposure to light.
11. A method of manufacturing according to claim 1, wherein the layer of optical structure material (4) is uniformly coated on the pattern of nanostructures (4) by means of evaporation, deposition and sputtering.
12. The method according to claim 1, wherein the pattern forming layer (2) is removed by a solution method using a microwave plasma apparatus.
13. A relief-type waveguide structure, comprising an optical waveguide element (6) and a plurality of grating units (7) formed on the surface of the optical waveguide element (6), wherein a nanostructure pattern (3) is formed between the plurality of grating units (7), the bottom of the nanostructure pattern (3) is connected with the surface of the optical waveguide element (6),
the grating unit (7) is of a cylinder structure, and the height-diameter ratio of the grating unit (7) is not less than 2.
14. A waveguide structure according to claim 13, characterized in that the end face shape of the grating elements (7) is circular or polygonal;
when the end surface of the grating unit (7) is in a circular shape, the height-diameter ratio of the grating unit (7) is the ratio of the height of the grating unit (7) to the diameter of the end surface;
when the end face of the grating unit (7) is polygonal, the height-diameter ratio of the grating unit (7) is the ratio of the height of the grating unit (7) to the longest diagonal length of the end face.
15. The waveguide structure according to claim 13, wherein the grating unit (7) is made of one or more of titanium dioxide, magnesium fluoride and aluminum oxide;
the heights of the grating units (7) are consistent;
the difference range of the refractive indexes of the grating unit (7) and the optical waveguide element (6) is 0-0.5.
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| CN202010220340.0A CN113448014A (en) | 2020-03-25 | 2020-03-25 | Relief type waveguide structure and manufacturing method thereof |
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