CN114280791B - Diffraction optical waveguide device and preparation method thereof - Google Patents
Diffraction optical waveguide device and preparation method thereof Download PDFInfo
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Abstract
The embodiment of the invention discloses a diffraction optical waveguide device and a preparation method thereof. The preparation method comprises the following steps: providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output; and forming a first grating structure in the first grating region, wherein the first grating structure is positioned on one side of the optical waveguide substrate, and is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same. The diffraction optical waveguide device prepared by the preparation method provided by the embodiment of the invention has consistent grating height, the uniformity of light emission is regulated by different refractive indexes of media in different areas, the processing difficulty of the grating is reduced, and the preparation cost of the diffraction optical waveguide device is greatly reduced.
Description
Technical Field
The embodiment of the invention relates to the technology of optical elements, in particular to a diffraction optical waveguide device and a preparation method thereof.
Background
Currently, relief grating waveguide technology is gaining widespread attention in near-eye display (e.g., augmented Reality, AR augmented reality) devices. Due to the convenience of nanoimprinting, and the advantages of the relief grating waveguide scheme over other waveguide schemes, such as a large field of view and a large eye movement range, relief grating waveguide schemes are being more and more widely studied.
The prior proposal of the relief grating waveguide mainly comprises a waveguide proposal based on a one-dimensional grating and a waveguide proposal based on a two-dimensional grating, wherein the two-dimensional grating waveguide proposal comprises an optical waveguide substrate, a coupling-in grating and a coupling-out grating which are arranged on the optical waveguide substrate, an image light beam emitted by an image light source is coupled into the optical waveguide substrate through the diffraction of the coupling-in grating and propagates in the optical waveguide substrate in a total reflection mode, and the coupling-out grating is used for diffracting and coupling the image light in the optical waveguide substrate into human eyes.
If the diffraction efficiency of the out-coupling grating is not changed, the image becomes darker gradually along the light ray in the transmission direction of the waveguide. Fig. 1 is a schematic diagram of an optical waveguide device fabricated by using grating groove depth modulation in the prior art, where uniform exit pupil is achieved by modulating the grating groove depth. Referring to fig. 1, light output by an optical system 101 is coupled into a substrate 102 through a coupling-in grating 103, and is transmitted to a coupling-out grating 104 by total reflection. Upon reaching the out-coupling grating 104, a portion of the light flux, i.e. rays 105, 106 and 107, is coupled out each time the out-coupling grating 104 is reached. The depth of the grooves of the out-coupling grating 104 gradually increases in the direction in which the light is transmitted in the optical waveguide device, and the coupling-out efficiency gradually increases accordingly, so that although the light flux reaching the out-coupling grating 104 before the diffraction output will be less than the light flux reaching the out-coupling grating 104 before, the light fluxes carried by the emitted light rays 105, 106 and 107 can be kept substantially uniform, so that the human eye sees the same brightness of the image when receiving the light rays 105, 106 and 107.
The uniformity of the light emission can be improved by adopting a groove depth modulation mode, but the etching difficulty of gratings with different heights in the actual processing process is high, and the manufacturing cost is high.
Disclosure of Invention
The embodiment of the invention provides a diffraction optical waveguide device and a preparation method thereof, wherein the grating height of the diffraction optical waveguide device prepared by the preparation method is consistent, the uniformity of light emission is regulated by different refractive indexes of mediums in different areas, the processing difficulty is reduced, and the preparation cost of the diffraction optical waveguide device is greatly reduced.
In a first aspect, an embodiment of the present invention provides a method for manufacturing a diffractive optical waveguide device, including:
providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output;
and forming a first grating structure in the first grating region, wherein the first grating structure is positioned on one side of the optical waveguide substrate, the first grating structure is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same.
Optionally, the optical waveguide substrate further includes a second grating region and a third grating region; the preparation method further comprises the following steps:
forming a second grating structure in the second grating region, and forming a third grating structure in the third grating region;
wherein the second grating structure and the third grating structure are both positioned on the same side of the optical waveguide substrate as the first grating structure; the second grating structure and the third grating structure are arranged along a first direction, the second grating structure and the first grating structure are arranged along a second direction, the second grating structure is used for coupling external light into the optical waveguide substrate, and the third grating structure is used for receiving the light beam transmitted by the second grating structure, and coupling the light beam into the first grating structure after expanding the beam; the first direction and the second direction are parallel to the plane where the optical waveguide substrate is located, and the first direction and the second direction are intersected.
Optionally, forming the first grating structure in the first grating region includes:
forming a metal film layer on the surface of one side of the optical waveguide substrate;
forming a photoresist layer on one side of the metal film layer far away from the optical waveguide substrate;
exposing and developing to expose the corresponding area of the crack of the first grating structure;
and forming the first grating structure by using an etching process, and removing the photoresist layer and the metal film layer in other areas.
Optionally, the metal film layer includes copper or chromium.
Optionally, the exposing comprises an interference exposure or an electron beam exposure.
Optionally, forming the first grating structure in the first grating region includes:
providing a grating structure mother board;
forming a fourth grating structure on the grating structure template by utilizing a photoetching process, wherein the fourth grating structure is complementary with the first grating structure in shape;
and the grating structure mother board is opposite to the optical waveguide substrate, and the first grating structure is formed by an imprinting process.
Optionally, after the first grating region forms the first grating structure, the method further includes:
and forming a protective layer between the grid lines of the first grating structure, wherein the refractive index of the protective layer is smaller than that of the optical waveguide substrate.
Optionally, the refractive index of the protective layer is greater than or equal to 1 and less than or equal to 1.1.
Optionally, the optical waveguide substrate includes a glass substrate, a semiconductor substrate, or an optical resin substrate.
In a second aspect, an embodiment of the present invention further provides a diffractive optical waveguide device, which is prepared by using the above preparation method.
The preparation method of the diffraction optical waveguide device provided by the embodiment of the invention comprises the following steps: providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output; and forming a first grating structure in the first grating region, wherein the first grating structure is positioned on one side of the optical waveguide substrate, and is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same. The first grating region of the optical waveguide substrate is provided with at least two grating subregions with different refractive indexes, the refractive indexes in the grating subregions are identical, the positions of the grating subregions are set according to the propagation step length of light rays in the optical waveguide substrate, each grating subregion corresponds to the coupling output of primary light rays, the heights of grating lines of each grating subregion are identical, the uniformity of light emission is regulated by utilizing the refractive index change of a medium, the height modulation of the grating lines is not needed, the grating processing difficulty is reduced, and the preparation cost of a diffraction optical waveguide device is greatly reduced.
Drawings
FIG. 1 is a schematic diagram of an optical waveguide device fabricated by grating groove depth modulation in the prior art;
FIG. 2 is a schematic diagram of the optical path of an optical waveguide device;
FIG. 3 is a schematic flow chart of a method for fabricating a diffractive optical waveguide device according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an optical waveguide substrate according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a partial cross-sectional structure of a diffractive optical waveguide device according to an embodiment of the present invention;
FIG. 6 is a schematic diagram showing a partial cross-sectional structure of another diffractive optical waveguide device according to an embodiment of the present invention
FIG. 7 is a schematic flow chart of another method for fabricating a diffractive optical waveguide device according to an embodiment of the present invention;
FIG. 8 is a schematic top view of a diffractive optical waveguide device according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram corresponding to a first grating structure forming process according to an embodiment of the present invention;
fig. 10 is a schematic diagram of a partial cross-sectional structure of another diffractive optical waveguide device according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. It should be noted that, the terms "upper", "lower", "left", "right", and the like in the embodiments of the present invention are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in the context, it will also be understood that when an element is referred to as being formed "on" or "under" another element, it can be directly formed "on" or "under" the other element or be indirectly formed "on" or "under" the other element through intervening elements. The terms "first," "second," and the like, are used for descriptive purposes only and not for any order, quantity, or importance, but rather are used to distinguish between different components. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The near-eye display (such as AR) device is generally worn in a manner similar to that of ordinary glasses, and is characterized in that the device can transmit light rays emitted by real world objects and can also enable light rays of virtual images to enter human eyes. The imaging system of the near-eye display device comprises an optical mechanical system and an optical waveguide device, wherein the optical mechanical system is a micro projector or a screen and is responsible for converting an electric signal into an optical signal and outputting a virtual image; the optical waveguide device is responsible for transmitting the output virtual image light to the position in front of human eyes, and enabling the light to enter human eyes to realize virtual image imaging. Light propagates along the optical waveguide by total reflection at the interface of the optical waveguide within the optical waveguide device, wherein the propagation step of the light beam represents the distance between the locations of incidence of two adjacent total reflections of the light beam at the same interface of the optical waveguide. In a practical scenario, different light beams transmitted in the optical waveguide may generate different propagation steps due to different angles of incidence of the light or different wavelengths of the light. Fig. 2 is a schematic diagram of the optical path of an optical waveguide device. Referring to fig. 2, the propagation step of the light ray 110 transmitted in the optical waveguide 100 is d 1 The propagation step of ray 120 is d 2 Propagation step d 1 Smaller than the propagation step d 2 . When light propagates into the outcoupling region 130, the light diffracts, and a part of the light is coupled out of the optical waveguide 100 while propagating forward, and the distance between the light outcoupling positions is the same as the propagation step length of the light beam in the optical waveguide 100. Because the propagation step length of the light ray 110 is shorter, the coupled-out light rays are denser, and the coupled-out light rays are sparser because the propagation step length of the light ray 120 is longer. If the relative positions of the human eye 140 and the coupling-out region 130 are fixed, as in the case of fig. 2, since the size of the entrance pupil of the human eye 140 is fixed, more light rays 110 with smaller intervals enter the human eye 140 (2 bundles in the figure), and less coupling-out light rays 120 with larger intervals are received by the human eye 140 (1 bundle in the figure). The brightness of the light imaged by the human eye 140 is the superposition of the brightness of the multiple beams received by the human eye 140, so that in the virtual image formed by the human eye 140, the image formed by the light 110 is brighter, and the image formed by the light 120 is darker. That is, the human eye 140 is fixed in position relative to the optical waveguide 100, and the brightness of the image formed by the light beams with different propagation steps is different, which may cause distortion of the virtual image information acquired by the human eye 140, for example, in the form of "dark bands", "distortion of the image brightness", etc., which is directly reflected in the virtual image imaging effect received by the human eye 140, which greatly restricts the practical use of the optical waveguide scheme.
At present, the mode of grating height modulation is favorable for improving the uniformity of light emission, but the grating with the height modulation has the defects of high processing difficulty and higher cost, and is not favorable for popularization and application.
In order to solve the above problems, an embodiment of the present invention provides a method for manufacturing a diffractive optical waveguide device. Fig. 3 is a schematic flow chart of a method for manufacturing a diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 3, a method for manufacturing a diffractive optical waveguide device according to an embodiment of the present invention includes:
step S110, providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output.
In this embodiment, the optical waveguide substrate may be a glass substrate, a semiconductor substrate or an optical resin substrate, and may be selected according to practical situations in implementation, which is not limited by the embodiment of the present invention. In specific implementation, the refractive index of the optical waveguide substrate is 1.5-2.0. Fig. 4 is a schematic structural diagram of an optical waveguide substrate according to an embodiment of the present invention, where fig. 4 schematically illustrates that the optical waveguide substrate 10 includes a first grating region 11, where the first grating region 11 includes four grating subregions 111 with the same shape and different refractive indexes, where each grating subregion is provided with a refractive index, for example, the refractive indexes of the four grating subregions 111 from left to right in fig. 4 may be set to 1.5, 1.6, 1.7, and 1.8, respectively, and in a specific implementation, the refractive index of each grating subregion may be set according to actual needs. The refractive index difference of the specific different regions may be formed by doping other materials during the manufacturing process, controlling different environmental conditions, and the like, which is not limited in the embodiment of the present invention.
Step S120, forming a first grating structure in the first grating area, wherein the first grating structure is positioned on one side of the optical waveguide substrate and is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same.
Fig. 5 is a schematic diagram illustrating a partial cross-sectional structure of a diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 5, the first grating region includes the first grating structure 112, and the grating heights of the first grating structure 112 at different positions are the same. When the refractive indices of the different regions of the optical waveguide substrate 10 are different, the coupling-out efficiency of the grating is different. Fig. 5 also schematically illustrates a schematic diagram of partial light transmission of the diffractive optical waveguide device, where, by way of example, light propagates from left to right, each grating subarea 111 corresponds to a coupling output of a primary light, that is, light is coupled in from left in fig. 5, and as a part of light is coupled out, total energy of light on right decreases, and as a refractive index of a medium is greater, a coupling-out efficiency of gratings with the same structure is higher, so that the refractive index of the optical waveguide substrate 10 may be set to be higher toward the right, so as to improve uniformity of light output. It can be understood that when the incident angles of the light rays are different, the propagation steps of the light rays in the diffraction grating device are different, and when the diffraction optical waveguide device is designed in this embodiment, the incident angle of the incident light rays is considered first, and the size of the grating subregions is designed according to the propagation steps of the light rays, so that each grating subregion realizes one-time coupling output. In the implementation, only the area within the specific range of the light output position can be set as the grating subarea, and the grating subarea which is uniformly divided can be also set similarly to the grating subarea in fig. 5. The diffraction optical waveguide device with uniform light output can be designed by comprehensively considering the factors such as the refractive index, the coupling efficiency of the grating structure, the residual energy of light after each coupling-out and the like. In addition, it should be noted that, the shape of each grating sub-region 111 shown in fig. 5 is the same, that is, the uniform distribution of the grating sub-regions 111 in the first grating region 11 is only schematic, and the shape and refractive index of the grating sub-regions 111 may be designed according to practical situations in practical implementation. The invention does not limit the manufacturing process of the first grating structure, for example, a photoetching process, an imprinting process and the like can be adopted, and the method can be selected according to actual conditions when being specifically implemented.
In further embodiments, multiple types of grating sub-regions may be provided according to different propagation steps, considering that the diffractive optical waveguide device may need to accommodate light rays at multiple angles of incidence. Fig. 6 is a schematic diagram illustrating a partial cross-sectional structure of another diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 6, propagation steps of the light a and the light b are different, and for the light a, a corresponding plurality of first-type grating sub-regions 111a are provided, and refractive indexes of the first-type grating sub-regions 111a sequentially increase from left to right; for the light ray b, a plurality of corresponding second-type grating subregions 111b are arranged, and the refractive indexes of the second-type grating subregions 111b are sequentially increased from left to right so as to match incident light rays with different angles. For light rays with more propagation steps, corresponding grating subareas can be set according to requirements.
According to the technical scheme, at least two grating subareas with different refractive indexes are arranged in the first grating area of the optical waveguide substrate, the refractive indexes in the grating subareas are the same, the positions of the grating subareas are arranged according to the propagation step length of light rays in the optical waveguide substrate, so that each grating subarea corresponds to the coupling output of primary light rays, the heights of grating lines of each grating subarea are the same, the uniformity of light emission is regulated by utilizing the refractive index change of a medium, the height modulation of the grating lines is not needed, the grating processing difficulty is reduced, and the preparation cost of a diffraction optical waveguide device is greatly reduced.
On the basis of the technical scheme, optionally, the optical waveguide substrate further comprises a second grating region and a third grating region. Fig. 7 is a schematic flow chart of a preparation method of another diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 7, the preparation method provided in this embodiment includes:
step S210, providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output.
Step S220, forming a first grating structure in the first grating area, wherein the first grating structure is positioned on one side of the optical waveguide substrate and is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same.
Step S230, forming a second grating structure in the second grating region and forming a third grating structure in the third grating region.
The second grating structure and the third grating structure are positioned on the same side of the optical waveguide substrate as the first grating structure; the second grating structure and the third grating structure are arranged along the first direction, the second grating structure and the first grating structure are arranged along the second direction, the second grating structure is used for coupling external light into the optical waveguide substrate, and the third grating structure is used for receiving the light beam transmitted by the second grating structure, and coupling the light beam into the first grating structure after expanding the light beam; the first direction and the second direction are parallel to the plane of the optical waveguide substrate, and the first direction and the second direction are intersected.
Fig. 8 is a schematic top view of a diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 8, the optical waveguide substrate 10 may optionally further include a second grating region 12 and a third grating region 13; the second grating region 12 includes a second grating structure 121, the third grating region 13 includes a third grating structure 131, and the second grating structure 121 and the third grating structure 131 are disposed on the same side of the optical waveguide substrate 10 as the first grating structure 112; the second grating structure 121 and the third grating structure 131 are arranged along the first direction x, the second grating structure 121 and the first grating structure 112 are arranged along the second direction y, the second grating structure 121 is used for coupling external light into the optical waveguide substrate 10, and the third grating structure 131 is used for receiving the light beam transmitted by the second grating structure 121, and coupling the light beam into the first grating structure 112 after expanding the light beam; the first direction x and the second direction y are parallel to the plane of the optical waveguide substrate 10, and the first direction x and the second direction y intersect.
It will be appreciated that the second grating region 12 is a coupling-in grating region of the diffractive optical waveguide device for receiving light incident from the outside (e.g. an optical-mechanical system), the third grating region 13 is a turning grating region of the diffractive optical waveguide device for changing the direction of light from the transmission and expanding the beam, and the first grating region 11 is a coupling-out grating region of the diffractive optical waveguide device for emitting modulated light.
Alternatively, within the first grating region 11, the refractive index of the grating sub-regions increases in sequence in a direction away from the third grating region 13. The arrangement is favorable for improving the uniformity of the emergent light, the specific refractive index and the shape of the grating subareas can be designed according to practical conditions, and the embodiment of the invention is not limited to the above.
In one embodiment, the grating of the diffractive optical waveguide device may be formed using a photolithographic process. Optionally, forming the first grating structure in the first grating region includes:
step S121, a metal film layer is formed on the surface of the optical waveguide substrate.
Wherein the etching rate of the metal film layer is different from that of the optical waveguide substrate, and optionally, the metal film layer may include copper or chromium.
Step S122, forming a photoresist layer on one side of the metal film layer far away from the optical waveguide substrate.
The photoresist layer may be coated on the metal film layer by spin coating, and the specific photoresist layer may be positive photoresist or negative photoresist, which is not limited in the embodiment of the present invention.
Step S123, exposing and developing to expose the corresponding area of the crack of the first grating structure.
Alternatively, the exposure method may select an interference exposure or an electron beam exposure.
Step S124, forming a first grating structure by using an etching process, and removing the photoresist layer and the metal film layer in other areas.
Fig. 9 is a schematic structural diagram corresponding to a first grating structure forming process according to an embodiment of the present invention. Referring to fig. 9, a metal film layer 20 is formed on a surface of one side of the optical waveguide substrate 10, then a photoresist layer 30 is formed on a side of the metal film layer 20 away from the optical waveguide substrate 10, after exposure and development steps, a crack corresponding region of the first grating structure is exposed, and finally, an etching process is used to form the first grating structure 112, and the photoresist layer and the metal film layer in other regions are removed, so that the diffraction optical waveguide device is formed.
In another embodiment, an embossing process may also be used to form the grating of the diffractive optical waveguide device. Optionally, forming the first grating structure in the first grating region includes:
step S125, providing a motherboard of grating structure.
Step S126, forming a fourth grating structure on the grating structure template by using a photolithography process, wherein the fourth grating structure is complementary to the first grating structure in shape.
The manufacturing process of the fourth grating structure may be similar to that of the first grating structure in the above embodiment, except that the fourth grating structure is complementary to the first grating structure in shape.
Step S127, the grating structure mother board is opposed to the optical waveguide substrate, and the first grating structure is formed by an imprinting process.
Optionally, after the first grating region forms the first grating structure, the method further includes:
and forming a protective layer between the grid lines of the first grating structure, wherein the refractive index of the protective layer is smaller than that of the optical waveguide substrate.
Fig. 10 is a schematic diagram illustrating a partial cross-sectional structure of another diffractive optical waveguide device according to an embodiment of the present invention. Referring to fig. 10, a protective layer 113 is disposed between the gate lines of the first grating structure 112, and the refractive index of the protective layer 113 is smaller than that of the optical waveguide substrate 10.
By providing the low refractive index protective layer 113 between the grating lines of the first grating structure 11, the grating structure can be protected, which is advantageous for packaging the diffractive optical waveguide device. The same heights of the protective layer 113 and the grating are merely illustrative, and the thickness of the protective layer 113 is not limited in implementation, and the refractive index of the protective layer is greater than or equal to 1 and less than or equal to 1.1 in implementation.
It should be noted that the manufacturing process of the second grating structure and the third grating structure may be similar to that of the first grating structure, which will not be described in detail herein.
The embodiment of the invention also provides a diffraction optical waveguide device, which is prepared by any preparation method provided by the embodiment, and can be used in a near-eye display device, wherein the near-eye display device can be a virtual reality display device or an augmented reality display device.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (10)
1. A method of fabricating a diffractive optical waveguide device, comprising:
providing an optical waveguide substrate, wherein the optical waveguide substrate comprises a first grating region, the first grating region of the optical waveguide substrate comprises at least two grating subregions with different refractive indexes, the refractive indexes in each grating subregion are the same, and each grating subregion corresponds to one-time light coupling output; designing the size of the grating subareas according to the propagation step length of the light rays; setting multiple types of grating subregions according to the propagation steps of different light rays;
and forming a first grating structure in the first grating region, wherein the first grating structure is positioned on one side of the optical waveguide substrate, the first grating structure is used for coupling out light rays in the optical waveguide substrate, and the heights of grating lines of the first grating structure are the same.
2. The method of manufacturing according to claim 1, wherein the optical waveguide substrate further comprises a second grating region and a third grating region; the preparation method further comprises the following steps:
forming a second grating structure in the second grating region, and forming a third grating structure in the third grating region;
wherein the second grating structure and the third grating structure are both positioned on the same side of the optical waveguide substrate as the first grating structure; the second grating structure and the third grating structure are arranged along a first direction, the first grating structure is arranged along a second direction, the second grating structure is used for coupling external light into the optical waveguide substrate, and the third grating structure is used for receiving the light beam transmitted by the second grating structure, and coupling the light beam into the first grating structure after expanding the light beam; the first direction and the second direction are parallel to the plane where the optical waveguide substrate is located, and the first direction and the second direction are intersected.
3. The method of manufacturing of claim 1, wherein forming a first grating structure within the first grating region comprises:
forming a metal film layer on the surface of one side of the optical waveguide substrate;
forming a photoresist layer on one side of the metal film layer far away from the optical waveguide substrate;
exposing and developing to expose the corresponding area of the crack of the first grating structure;
and forming the first grating structure by using an etching process, and removing the photoresist layer and the metal film layer in other areas.
4. A method of manufacturing according to claim 3, wherein the metal film layer comprises copper or chromium.
5. A method of preparation according to claim 3, wherein the exposure comprises an interference exposure or an electron beam exposure.
6. The method of manufacturing of claim 1, wherein forming a first grating structure in the first grating region comprises:
providing a grating structure mother board;
forming a fourth grating structure on the grating structure template by utilizing a photoetching process, wherein the fourth grating structure is complementary with the first grating structure in shape;
and the grating structure mother board is opposite to the optical waveguide substrate, and the first grating structure is formed by an imprinting process.
7. The method of manufacturing according to claim 1, further comprising, after the first grating region forms the first grating structure:
and forming a protective layer between the grid lines of the first grating structure, wherein the refractive index of the protective layer is smaller than that of the optical waveguide substrate.
8. The method of claim 7, wherein the protective layer has a refractive index greater than or equal to 1 and less than or equal to 1.1.
9. The method of manufacturing according to claim 1, wherein the optical waveguide substrate comprises a glass substrate, a semiconductor substrate, or an optical resin substrate.
10. A diffractive optical waveguide device characterized by being produced by the production method according to any one of claims 1 to 9.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB201205383D0 (en) * | 2012-03-27 | 2012-05-09 | Bae Systems Plc | Improvements in or relating to optical waveguides |
| CN104280885A (en) * | 2014-09-27 | 2015-01-14 | 郑敏 | Large-exit-pupil holographic waveguide glasses system |
| FI20175509A1 (en) * | 2017-06-02 | 2018-12-03 | Dispelix Oy | Diffractive element with doubly periodic gratings |
| CN111722317A (en) * | 2020-07-14 | 2020-09-29 | 北京至格科技有限公司 | Diffraction light waveguide lens |
| CN112099140A (en) * | 2020-10-29 | 2020-12-18 | 歌尔股份有限公司 | Diffraction optical waveguide with uniform emergent brightness, manufacturing method and head-mounted display device |
| CN113302542A (en) * | 2018-11-09 | 2021-08-24 | 脸谱科技有限责任公司 | Angle selective grating coupler for waveguide display |
| WO2021169405A1 (en) * | 2020-02-28 | 2021-09-02 | 苏州苏大维格科技集团股份有限公司 | Optical waveguide lens capable of multi-directional diffraction expansion, and augmented reality display device |
| CN114280790A (en) * | 2021-12-29 | 2022-04-05 | 材料科学姑苏实验室 | Diffraction light waveguide device and near-to-eye display equipment |
-
2021
- 2021-12-29 CN CN202111638350.7A patent/CN114280791B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB201205383D0 (en) * | 2012-03-27 | 2012-05-09 | Bae Systems Plc | Improvements in or relating to optical waveguides |
| CN104280885A (en) * | 2014-09-27 | 2015-01-14 | 郑敏 | Large-exit-pupil holographic waveguide glasses system |
| FI20175509A1 (en) * | 2017-06-02 | 2018-12-03 | Dispelix Oy | Diffractive element with doubly periodic gratings |
| CN113302542A (en) * | 2018-11-09 | 2021-08-24 | 脸谱科技有限责任公司 | Angle selective grating coupler for waveguide display |
| WO2021169405A1 (en) * | 2020-02-28 | 2021-09-02 | 苏州苏大维格科技集团股份有限公司 | Optical waveguide lens capable of multi-directional diffraction expansion, and augmented reality display device |
| CN111722317A (en) * | 2020-07-14 | 2020-09-29 | 北京至格科技有限公司 | Diffraction light waveguide lens |
| CN112099140A (en) * | 2020-10-29 | 2020-12-18 | 歌尔股份有限公司 | Diffraction optical waveguide with uniform emergent brightness, manufacturing method and head-mounted display device |
| CN114280790A (en) * | 2021-12-29 | 2022-04-05 | 材料科学姑苏实验室 | Diffraction light waveguide device and near-to-eye display equipment |
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|---|---|
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