WO2024103978A1 - 光学传输结构及其制作方法、显示装置 - Google Patents

光学传输结构及其制作方法、显示装置 Download PDF

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Publication number
WO2024103978A1
WO2024103978A1 PCT/CN2023/121893 CN2023121893W WO2024103978A1 WO 2024103978 A1 WO2024103978 A1 WO 2024103978A1 CN 2023121893 W CN2023121893 W CN 2023121893W WO 2024103978 A1 WO2024103978 A1 WO 2024103978A1
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Prior art keywords
optical waveguide
grating
coupling
transmission structure
optical
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PCT/CN2023/121893
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English (en)
French (fr)
Inventor
袁广才
郭康
陈宏�
谷新
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京东方科技集团股份有限公司
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Publication of WO2024103978A1 publication Critical patent/WO2024103978A1/zh

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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
    • 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
    • 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
    • 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
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/34—Optical coupling means utilising prism or grating

Definitions

  • the present disclosure relates to the field of display technology, and in particular to an optical transmission structure and a manufacturing method thereof, and a display device.
  • the concept of "metaverse” was proposed, virtual reality (VR) and augmented reality (AR) have received more attention, and many technology companies have increased their research and development efforts, hoping to develop related products for consumer applications as soon as possible.
  • VR virtual reality
  • AR augmented reality
  • the most popular is AR glasses, and its implementation methods are generally divided into geometric optics and diffraction optics.
  • the diffraction optics solution is favored by industry players because the product is lighter, thinner and more transparent.
  • the surface relief grating (SRG) diffraction optical waveguide is currently a solution that has received more attention because it is more mass-producible.
  • SRG waveguide gratings mainly include rectangular gratings, tilted gratings and blazed gratings.
  • rectangular gratings are the most widely used grating type in the current market due to the lowest difficulty in preparation process.
  • the light utilization rate of SRG waveguide gratings is not high, resulting in low brightness of the image that finally enters the human eye.
  • the technical problem to be solved by the present disclosure is to provide an optical transmission structure and a manufacturing method thereof, and a display device, which can improve the utilization rate of light energy.
  • the embodiments of the present disclosure provide the following technical solutions:
  • an optical transmission structure comprising:
  • an in-coupling grating located on a first surface of the optical waveguide and an out-coupling grating located on a second surface of the optical waveguide, wherein the in-coupling grating is used to couple incident light into the optical waveguide;
  • the first surface and the second surface form a preset angle, so that the zero-order diffraction light beam transmitted into the optical waveguide through the coupling-in grating generates total reflection in the optical waveguide, and the coupling-out grating is used to couple the outgoing light out of the optical waveguide.
  • the incident light enters the optical transmission structure perpendicularly to the first surface.
  • the incident light is image light.
  • the grating periods of the in-coupling grating and the out-coupling grating are the same.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating, and a period of the rectangular grating is 300-600 nm.
  • the height of the rectangular grating is 30-500 nm.
  • the optical waveguide comprises:
  • a prism portion is disposed on the second surface of the optical waveguide body, wherein the prism portion includes the first surface protruding from the optical waveguide body.
  • the refractive index of the prism portion is n 1
  • the refractive index of the optical waveguide body is n 2
  • the incident angle of the zero-order diffraction beam incident on the optical waveguide body is ⁇ 1
  • the refractive angle is ⁇ 2
  • ⁇ 1 and ⁇ 2 satisfy:
  • n 1 sin ⁇ 1 n 2 sin ⁇ 2 , wherein ⁇ 2 ⁇ c , and ⁇ c is the total reflection critical angle of the optical waveguide body.
  • L is the width of the prism portion in a first direction
  • the first direction is parallel to the second surface and is the direction from the coupling-in grating to the coupling-out grating
  • S is the transmission step length of the zero-order diffraction light beam in the optical waveguide body
  • S 2dtan ⁇ 2
  • L and S satisfy: L ⁇ S, where d is the thickness of the optical waveguide body.
  • n 1 ranges from 1.5 to 2.0;
  • n 2 1.5 to 2.0.
  • n1 is equal to n2 .
  • the optical waveguide comprises:
  • An optical waveguide body wherein a light incident surface and a light emitting surface of the optical waveguide body form a preset angle; wherein the light incident surface is the first surface, the light emitting surface is the second surface, and the preset angle is greater than a critical angle of total reflection of the optical waveguide body.
  • the embodiment of the present disclosure also provides a display device, comprising the optical transmission structure as described above.
  • the present disclosure also provides a method for manufacturing an optical transmission structure, including:
  • the first surface and the second surface form a preset angle, so that the zero-order diffraction light beam transmitted into the optical waveguide through the coupling-in grating generates total reflection in the optical waveguide, and the coupling-out grating is used to couple the outgoing light out of the optical waveguide.
  • forming the optical waveguide includes:
  • the prism portion is attached to the second surface of the optical waveguide body, so that the first surface of the prism portion protrudes from the optical waveguide body.
  • forming the optical waveguide includes:
  • the waveguide substrate is cut to form an optical waveguide body and a prism portion located on the second surface of the optical waveguide body, wherein the prism portion includes the first surface protruding from the optical waveguide body.
  • forming an incoupling grating on the first surface of the optical waveguide comprises:
  • a flexible substrate carrying the coupling-in grating is attached to the waveguide coupling-in region of the first surface.
  • forming an outcoupling grating on the second surface of the optical waveguide comprises:
  • a flexible substrate carrying the outcoupling grating is attached to the waveguide outcoupling region of the second surface.
  • forming the optical waveguide includes:
  • the waveguide substrate is cut to form an optical waveguide body, wherein a light incident surface and a light emitting surface of the optical waveguide body form a preset angle; wherein the light incident surface is the first surface, the light emitting surface is the second surface, and the preset angle is greater than a critical angle of total reflection of the optical waveguide body.
  • the zero-order diffraction light beam with the highest energy is used as the information transmission carrier and transmitted by total reflection in the optical waveguide, which can improve the overall light energy utilization rate of the optical transmission structure.
  • FIG1 is a schematic diagram showing the distribution of diffraction efficiency of a conventional rectangular grating
  • FIGS. 2 and 3 are schematic diagrams of light propagation of an optical transmission structure according to an embodiment of the present disclosure
  • FIG4 is a schematic diagram of light propagation of an optical transmission structure according to another embodiment of the present disclosure.
  • FIG5 is a schematic diagram of a process for manufacturing an optical transmission structure according to an embodiment of the present disclosure.
  • FIG6 is a schematic diagram of a process for fabricating a metal transition structure on a silicon substrate according to an embodiment of the present disclosure
  • FIG7 is a schematic diagram of manufacturing an imprint template according to an embodiment of the present disclosure.
  • FIG8 is a schematic diagram of manufacturing a rectangular grating on a flexible substrate according to an embodiment of the present disclosure
  • FIG9 is a schematic diagram of a process for manufacturing an optical transmission structure according to another embodiment of the present disclosure.
  • FIG10 is a schematic diagram of a process of manufacturing a prism portion and a coupling grating according to an embodiment of the present disclosure
  • FIG11 is a schematic diagram of a process for fabricating a metal transition structure on a silicon substrate in another embodiment of the present disclosure
  • FIG12 is a schematic diagram of manufacturing an imprint template according to another embodiment of the present disclosure.
  • FIG13 is a schematic diagram of manufacturing an optical waveguide body and an outcoupling grating according to another embodiment of the present disclosure.
  • FIG14 is a schematic diagram of a process for manufacturing an optical transmission structure according to another embodiment of the present disclosure.
  • FIG. 15 is a schematic diagram of a process for manufacturing an optical transmission structure according to yet another embodiment of the present disclosure.
  • the energy that accounts for the largest proportion includes the transmitted T 0 order (i.e., the zeroth order diffraction order) and the transmitted T ⁇ 1 order diffraction order (i.e., the positive first order diffraction order and the negative first order diffraction order), among which the T +1 diffraction order is the information transmission carrier.
  • Figure 1 is a schematic diagram of the working principle of AR glasses with rectangular gratings as coupling gratings and coupling gratings.
  • the diffraction efficiency of the T -1 and T +1 diffraction orders is equal (generally less than 20%), and is much lower than the T 0 order diffraction efficiency (generally about 60%), resulting in low light energy utilization and low brightness of the image entering the human eye.
  • Embodiments of the present disclosure provide an optical transmission structure and a manufacturing method thereof, and a display device, which can improve light energy utilization.
  • An embodiment of the present disclosure provides an optical transmission structure, comprising:
  • An incoupling grating located on a first surface of the optical waveguide and an incoupling grating located on a second surface of the optical waveguide An out-coupling grating on the optical waveguide, wherein the in-coupling grating is used to couple incident light into the optical waveguide;
  • the first surface and the second surface form a preset angle, so that the zero-order diffraction light beam transmitted into the optical waveguide through the coupling-in grating generates total reflection in the optical waveguide, and the coupling-out grating is used to couple the outgoing light out of the optical waveguide.
  • the zero-order diffraction light beam with the highest energy is used as an information transmission carrier and transmitted through total reflection in the optical waveguide, which can improve the overall light energy utilization rate of the optical transmission structure.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating.
  • the coupling-in grating and/or the coupling-out grating is not limited to a rectangular grating, and may also be other types of gratings, such as a blazed grating, a tilted grating, etc.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating
  • the zero-order diffraction order (T 0 order) has the highest energy (generally ⁇ 60%) due to the intrinsic characteristics of the rectangular grating, which is much higher than the T ⁇ 1 diffraction order (T ⁇ 1 diffraction efficiency is the same, generally ⁇ 20%), and therefore, the light efficiency can be improved by more than 3 times.
  • the optical waveguide includes: an optical waveguide body 01; a prism portion 03 disposed on the second surface 01a of the optical waveguide body 01, the prism portion 03 includes the first surface 03b protruding from the optical waveguide body 01, and the inclined surface of the prism portion 03 is on the same plane as the second surface 01a, so that the first surface 03b and the second surface 01a form a preset angle.
  • the prism portion 03 and the optical waveguide body 01 can be an integral structure, or two different structures bonded together.
  • the coupling-in grating 021 is arranged in the waveguide coupling-in region on the first surface 03b of the prism portion 03, and the coupling-out grating 022 is arranged in the waveguide coupling-out region on the second surface 01a of the optical waveguide body 01.
  • the coupling-in grating 021 After the light is incident on the coupling-in grating 021 in the waveguide coupling-in region, diffraction occurs.
  • the light diffracted by the coupling-in grating 021 is transmitted in the optical waveguide.
  • the coupling-out grating 022 arranged in the waveguide coupling-out region it is emitted after being diffracted by the coupling-out grating 022.
  • the angle between the first surface 03b of the prism portion 03 and the second surface 01a of the optical waveguide body 01 is ⁇ 1 .
  • the incident angle of the zero-order diffraction light beam entering the optical waveguide body 01 is ⁇ 1
  • the refraction angle is ⁇ 2 .
  • n 1 sin ⁇ 1 n 2 sin ⁇ 2 , where ⁇ 2 ⁇ c , ⁇ c is the critical angle of total reflection of the optical waveguide body.
  • the zero-order diffraction light beam can be totally reflected and propagated in the optical waveguide body 01, wherein the refractive index of the prism portion is n 1 and the refractive index of the optical waveguide body is n 2 .
  • the value range of n 1 can be 1.5 to 2.0; the value range of n 2 is 1.5 to 2.0.
  • n 1 and n 2 can be equal or unequal.
  • the optical waveguide includes: an optical waveguide body 01; a preset angle is formed between the light incident surface and the light emitting surface of the optical waveguide body 01; wherein the light incident surface is a first surface 01b, the light emitting surface is a second surface 01a, and the preset angle ⁇ 3 is greater than the critical angle of total reflection of the optical waveguide body 01.
  • the coupling-in grating 021 is arranged in the waveguide coupling-in region on the first surface 01b, and the coupling-out grating 022 is arranged in the waveguide coupling-out region on the second surface 01a of the optical waveguide body 01.
  • the coupling-in grating 021 After the light is incident on the coupling-in grating 021 in the waveguide coupling-in region, diffraction occurs.
  • the light diffracted by the coupling-in grating 021 is transmitted in the optical waveguide.
  • the coupling-out grating 022 arranged in the waveguide coupling-out region, the light is diffracted by the coupling-out grating 022 and then emitted.
  • the angle between the first surface 01b of the optical waveguide body 01 and the second surface 01a of the optical waveguide body 01 is ⁇ 3 , ⁇ 3 ⁇ c , ⁇ c is the critical angle of total reflection of the optical waveguide body, so that when the incident light enters the optical transmission structure perpendicular to the first surface 01b, the zero-order diffraction light beam can be totally reflected and propagated in the optical waveguide body 01.
  • the incident light is image light
  • the optical transmission structure can be applied to a display device such as an AR helmet.
  • the optical transmission structure can realize the transmission of image light and ensure the brightness of the image entering the human eye.
  • the grating periods of the coupling-in grating 021 and the coupling-out grating 022 may be the same, which is not limited in this embodiment.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating, and the period of the rectangular grating can be 300-600nm, such as 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, or other values.
  • the diffraction efficiency of the optical transmission structure is different at different periods, and a higher diffraction efficiency can be obtained when the period of the rectangular grating is 300-600nm.
  • the height of the rectangular grating can be 30-500nm, such as 30nm, 350nm, 400nm, 450nm, 500nm, or other values. At different heights, the diffraction efficiency of the optical transmission structure is different. When the height of the rectangular grating is 30-500nm, a higher diffraction efficiency can be obtained.
  • L is the width of the prism portion in a first direction
  • the first direction is parallel to the second surface 01a and is a direction from the coupling-in grating 021 to the coupling-out grating 022
  • S is a transmission step length of the zero-order diffraction light beam in the optical waveguide body 01
  • S 2dtan ⁇ 2
  • L and S satisfy: L ⁇ S, wherein d is the thickness of the optical waveguide body 01, so as to avoid the prism portion 03 being too large in the first direction, resulting in the zero-order diffraction light beam entering the prism portion 03 again for transmission after entering the optical waveguide body 01, thereby reducing the energy of the zero-order diffraction light beam propagating in the optical waveguide body 01, and further reducing the energy of the light coupled out by the coupling-out grating 022.
  • the value of d can be 0.1m-5mm, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm and 5mm, and can also be other values. If the value of d is too large, the thickness of the optical transmission structure will be too large, which is not conducive to the thinness of the optical transmission structure; if the value of the optical transmission structure is too small, it will affect the light transmission quality of the optical transmission structure. Therefore, the value of d is preferably 0.1m-5mm.
  • the embodiment of the present disclosure also provides a display device, comprising the optical transmission structure as described above.
  • the display device includes but is not limited to: a radio frequency unit, a network module, an audio output unit, an input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply.
  • a radio frequency unit a network module
  • an audio output unit an input unit
  • a sensor a sensor
  • a display unit a user input unit
  • an interface unit a memory
  • a processor and a power supply.
  • the structure of the above-mentioned display device does not constitute a limitation on the display device, and the display device may include more or less of the above-mentioned components, or a combination of certain components, or different component arrangements.
  • the display device includes but is not limited to a display, a mobile phone, a tablet computer, a television, a wearable electronic device, a navigation display device, etc.
  • the display device of this embodiment may be a VR display device and an AR display device, for example, may be AR glasses.
  • the present disclosure also provides a method for manufacturing an optical transmission structure, including:
  • the first surface and the second surface form a preset angle, so that the zero-order diffraction light beam transmitted into the optical waveguide through the coupling-in grating generates total reflection in the optical waveguide, and the coupling-out grating is used to couple the outgoing light out of the optical waveguide.
  • the zero-order diffraction light beam with the highest energy is used as an information transmission carrier and transmitted through total reflection in the optical waveguide, which can improve the overall light energy utilization rate of the optical transmission structure.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating.
  • the coupling-in grating and/or the coupling-out grating is not limited to a rectangular grating, and may also be other types of gratings, such as a blazed grating, a tilted grating, etc.
  • the coupling-in grating and/or the coupling-out grating is a rectangular grating
  • the zero-order diffraction order (T 0 order) has the highest energy (generally ⁇ 60%) due to the intrinsic characteristics of the rectangular grating, which is much higher than the T ⁇ 1 diffraction order (T ⁇ 1 diffraction efficiency is the same, generally ⁇ 20%), and therefore, the light efficiency can be improved by more than 3 times.
  • the optical waveguide includes: an optical waveguide body 01; a prism portion 03 disposed on the second surface 01a of the optical waveguide body 01, the prism portion 03 includes the first surface 03b protruding from the optical waveguide body 01, and the inclined surface of the prism portion 03 is on the same plane as the second surface 01a, so that the first surface 03b and the second surface 01a form a preset angle.
  • the prism portion 03 and the optical waveguide body 01 can be an integral structure, or two different structures bonded together.
  • the coupling-in grating 021 is arranged in the waveguide coupling-in region on the first surface 03b of the prism portion 03, and the coupling-out grating 022 is arranged in the waveguide coupling-out region on the second surface 01a of the optical waveguide body 01.
  • the coupling-in grating 021 After the light is incident on the coupling-in grating 021 in the waveguide coupling-in region, diffraction occurs.
  • the light diffracted by the coupling-in grating 021 is transmitted in the optical waveguide.
  • the coupling-out grating 022 arranged in the waveguide coupling-out region it is emitted after being diffracted by the coupling-out grating 022.
  • the angle between the first surface 03b of the prism portion 03 and the second surface 01a of the optical waveguide body 01 is ⁇ 1 .
  • the incident angle of the zero-order diffraction light beam entering the optical waveguide body 01 is ⁇ 1
  • the refraction angle is ⁇ 2 .
  • n 1 sin ⁇ 1 n 2 sin ⁇ 2 , where ⁇ 2 ⁇ c , ⁇ c is the critical angle of total reflection of the optical waveguide body.
  • the zero-order diffraction light beam can be totally reflected and propagated in the optical waveguide body 01, wherein the refractive index of the prism portion is n 1 and the refractive index of the optical waveguide body is n 2 .
  • the value range of n 1 can be 1.5 to 2.0; the value range of n 2 is 1.5 to 2.0.
  • n 1 and n 2 can be equal or unequal.
  • the optical waveguide includes: an optical waveguide body 01; a preset angle is formed between the light incident surface and the light emitting surface of the optical waveguide body 01; wherein the light incident surface is a first surface 01b, the light emitting surface is a second surface 01a, and the preset angle ⁇ 3 is greater than the critical angle of total reflection of the optical waveguide body 01.
  • the coupling-in grating 021 is arranged in the waveguide coupling-in region on the first surface 01b, and the coupling-out grating 022 is arranged in the waveguide coupling-out region on the second surface 01a of the optical waveguide body 01.
  • the coupling-in grating 021 After the light is incident on the coupling-in grating 021 in the waveguide coupling-in region, diffraction occurs.
  • the light diffracted by the coupling-in grating 021 is transmitted in the optical waveguide.
  • the coupling-out grating 022 arranged in the waveguide coupling-out region, the light is diffracted by the coupling-out grating 022 and then emitted.
  • the angle between the first surface 01b of the optical waveguide body 01 and the second surface 01a of the optical waveguide body 01 is ⁇ 3 , ⁇ 3 ⁇ c , ⁇ c is the critical angle of total reflection of the optical waveguide body, so that when the incident light enters the optical transmission structure perpendicular to the first surface 01b, the zero-order diffraction light beam can be totally reflected and propagated in the optical waveguide body 01.
  • L is the width of the prism portion in a first direction
  • the first direction is parallel to the second surface 01a and is a direction from the coupling-in grating 021 to the coupling-out grating 022
  • S is a transmission step length of the zero-order diffraction light beam in the optical waveguide body 01
  • S 2dtan ⁇ 2
  • L and S satisfy: L ⁇ S, wherein d is the thickness of the optical waveguide body 01, so as to avoid the prism portion 03 being too large in the first direction, resulting in the zero-order diffraction light beam entering the prism portion 03 again for transmission after entering the optical waveguide body 01, thereby reducing the energy of the zero-order diffraction light beam propagating in the optical waveguide body 01, and further reducing the energy of the light coupled out by the coupling-out grating 022.
  • optical transmission structure of the present disclosure is further introduced below in conjunction with FIG. 4 to FIG. 15 and specific embodiments.
  • a waveguide substrate with a suitable thickness may be provided; the waveguide substrate may be cut to form an optical waveguide body 01, wherein the light incident surface and the light emitting surface of the optical waveguide body are A preset angle is formed between the first surface 01b and the second surface 01a; wherein the light incident surface is the first surface 01b, the light exiting surface is the second surface 01a, and the preset angle is greater than the critical angle of total reflection of the optical waveguide body 01.
  • a waveguide substrate with a suitable thickness can be provided; the waveguide substrate is cut to form the optical waveguide body and the prism portion located on the second surface of the optical waveguide body, and the prism portion includes the first surface protruding from the optical waveguide body.
  • a waveguide material with a suitable thickness is selected as the waveguide substrate 011; as shown in FIG5b , the waveguide substrate 011 is cut into a first transition structure 012 by means of diamond cutting or laser cutting, and the first transition structure 012 is a whole composed of an optical waveguide body and a prism portion; as shown in FIG5c , an out-coupling grating 022 is prepared on the first transition structure 012 by cutting and grinding means; as shown in FIG5d , an in-coupling grating 021 is prepared on the first transition structure 012 by cutting and grinding means, and the optical transmission structure of the present embodiment can be obtained.
  • an optical transmission structure can also be formed by a bonding process.
  • Forming the optical waveguide includes: forming the optical waveguide body and the prism portion separately; attaching the prism portion to the second surface of the optical waveguide body so that the first surface of the prism portion protrudes from the optical waveguide body.
  • the coupling-in grating is made on a flexible substrate by a nanoimprinting method; the flexible substrate carrying the coupling-in grating is attached to the waveguide coupling-in region of the first surface.
  • the coupling-out grating is made on a flexible substrate by a nanoimprinting method; the flexible substrate carrying the coupling-out grating is attached to the waveguide coupling-out region of the second surface.
  • a metal layer 05 and a photoresist 16 are formed on a silicon substrate 04, wherein the metal layer 05 may be made of Mo; as shown in FIG6b, the photoresist 16 is exposed and developed to form a pattern of the photoresist 16; as shown in FIG6c, the metal layer 05 is etched using the pattern of the photoresist 16 as a mask to form a metal transition structure 051.
  • a UV adhesive is formed on the silicon substrate 04 formed with the metal transition structure 051, and the UV adhesive is cured to form an imprint template 06; as shown in Figure 7c, the silicon substrate 04 formed with the metal transition structure 051 is removed to obtain an imprint template 06 formed with a groove 061, wherein the shape of the groove 061 matches the shape of the metal transition structure 051.
  • an adhesive layer 08 , a flexible substrate 09 and a grating material layer 10 are formed on the hard substrate 07 , wherein the hard substrate 07 may be a quartz substrate or a glass substrate, the flexible substrate 09 may be a polyimide film, and the grating material layer 10 may be an embossed adhesive; as shown in FIG8b , an embossing template 06 formed with a groove 061 is pressed onto the grating material layer 10; as shown in FIG8c , after removing the embossing template 06 formed with the groove 061 , the grating material layer 10 is formed into a rectangular grating 02 matching the shape of the groove 061 ; as shown in FIG8d , the hard substrate 07 and the adhesive layer 08 are removed by laser stripping to obtain a flexible substrate 09 carrying the rectangular grating 02 .
  • a waveguide material of suitable thickness is selected as the waveguide substrate 011; as shown in FIG9b , the waveguide substrate 011 is cut into a first transition structure 012 by means of diamond cutting or laser cutting, and the first transition structure 012 is a whole composed of an optical waveguide body and a prism portion; as shown in FIG9c , a rectangular grating 02 with different grating parameters is attached to the waveguide coupling-in region and the waveguide coupling-out region by a bonding process, and the optical transmission structure of the present embodiment can be obtained.
  • an optical transmission structure may be formed by a bonding process.
  • a metal layer 05 and a photoresist 16 are formed on a silicon substrate 04, wherein the metal layer 05 may be made of Mo; as shown in FIG6b, the photoresist 16 is exposed and developed to form a pattern of the photoresist 16; as shown in FIG6c, the metal layer 05 is etched using the pattern of the photoresist 16 as a mask to form a metal transition structure 051.
  • a UV adhesive is formed on the silicon substrate 04 formed with the metal transition structure 051, and the UV adhesive is cured to form an imprint template 06; as shown in Figure 7c, the silicon substrate 04 formed with the metal transition structure 051 is removed to obtain an imprint template 06 formed with a groove 061, wherein the shape of the groove 061 matches the shape of the metal transition structure 051.
  • a grating material layer 10 is formed on a hard substrate 07, wherein the hard substrate 07 may be a quartz substrate or a glass substrate, and the grating material layer 10 may be made of an imprinting glue; as shown in FIG10b , an imprinting template 06 formed with a groove 061 is pressed onto the grating material layer 10; as shown in FIG10c , after removing the imprinting template 06 formed with the groove 061, the grating material layer 10 is formed into a coupling grating 021 matching the shape of the groove 061; as shown in FIG10d , the hard substrate 07 formed with the coupling grating 021 is laser cut to obtain a prism portion 03 and a coupling grating 021.
  • a metal layer 05 and a photoresist 16 are formed on the silicon substrate 04 , wherein the metal layer 05 may be made of Mo; as shown in FIG. 11b , the photoresist 16 is exposed and developed to form a pattern of the photoresist 16 ; as shown in FIG. 11c , the metal layer 05 is etched using the pattern of the photoresist 16 as a mask to form a metal transition structure 051 .
  • a UV adhesive is formed on the silicon substrate 04 formed with the metal transition structure 051, and the UV adhesive is cured to form an imprint template 06; as shown in Figure 12c, the silicon substrate 04 formed with the metal transition structure 051 is removed to obtain an imprint template 06 formed with a groove 061, wherein the shape of the groove 061 matches the shape of the metal transition structure 051.
  • an optical waveguide body 01 and a grating material layer 10 are formed; as shown in Figure 13b, an imprinting template 06 formed with a groove 061 is pressed onto the grating material layer 10; as shown in Figure 13c, after removing the imprinting template 06 formed with the groove 061, the grating material layer 10 is formed into a coupling-out grating 022 matching the shape of the groove 061.
  • the prism portion 03 formed with the coupling-in grating 021 is bonded to the optical waveguide body 01 formed with the coupling-out grating 022 by adhesive, thereby obtaining the optical transmission structure of the present embodiment.
  • the optical transmission structure when the refractive index of the optical waveguide body is not equal to the refractive index of the prism portion, the optical transmission structure may be formed by a cutting process.
  • a metal layer 05 and a photoresist 16 are formed on a silicon substrate 04, wherein the metal layer 05 may be made of Mo; as shown in FIG6b, the photoresist 16 is exposed and developed to form a pattern of the photoresist 16; as shown in FIG6c, the metal layer 05 is etched using the pattern of the photoresist 16 as a mask to form a metal transition structure 051.
  • a UV adhesive is formed on the silicon substrate 04 formed with the metal transition structure 051, and the UV adhesive is cured to form an imprint template 06; as shown in Figure 7c, the silicon substrate 04 formed with the metal transition structure 051 is removed to obtain an imprint template 06 formed with a groove 061, wherein the shape of the groove 061 matches the shape of the metal transition structure 051.
  • a bonding layer 08, a flexible substrate 09 and a grating material layer 10 are formed on the hard substrate 07, wherein the hard substrate 07 can be a quartz substrate or a glass substrate, the flexible substrate 09 can be a polyimide film, and the grating material layer 10 can be an embossed adhesive; as shown in FIG8b, The imprint template 06 formed with the groove 061 is pressed onto the grating material layer 10; as shown in FIG8c , after the imprint template 06 formed with the groove 061 is removed, the grating material layer 10 is formed into a rectangular grating 02 matching the shape of the groove 061; as shown in FIG8d , the hard substrate 07 and the bonding layer 08 are removed by laser stripping to obtain a flexible substrate 09 carrying the rectangular grating 02.
  • a hard substrate 07 is provided.
  • the hard substrate 07 can be a quartz substrate or a glass substrate.
  • the hard substrate 07 is cut to obtain a plurality of prism portions 03.
  • the prism portion 03 is bonded to the optical waveguide body 01 by adhesive.
  • a rectangular grating 02 having different grating parameters is attached to the waveguide coupling-in region of the prism portion 03 and the waveguide coupling-out region of the optical waveguide body 01 by a bonding process, thereby obtaining the optical transmission structure of the present embodiment as shown in FIG15d.
  • This embodiment uses the transmitted zero-order diffraction light beam with the highest diffraction efficiency of the rectangular grating as the information transmission carrier, rather than the conventional transmitted first-order diffraction light beam, thereby greatly improving the overall light efficiency of the optical transmission structure.
  • each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.
  • the description is relatively simple, and the relevant parts can be referred to the partial description of the product embodiments.

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Abstract

一种光学传输结构及其制作方法、显示装置，属于显示技术领域。其中，光学传输结构，包括：光波导；位于光波导的第一表面（03b）上的耦入光栅（021）和位于光波导的第二表面（01a）上的耦出光栅（022），耦入光栅（021）用于将入射光线耦入光波导中；其中，第一表面（01a）与第二表面（03b）之间成预设角度，使得经耦入光栅（021）传输到光波导内的零级衍射光束在光波导内产生全反射，耦出光栅（022）用于将出射光线耦出光波导。由此能够提高光能利用率。

Description

光学传输结构及其制作方法、显示装置
相关申请的交叉引用
本申请主张在2022年11月16日在中国提交的中国专利申请号No.202211434561.3的优先权，其全部内容通过引用包含于此。
技术领域
本公开涉及显示技术领域，特别是指一种光学传输结构及其制作方法、显示装置。
背景技术
自“元宇宙”概念提出以来，虚拟现实(VR)和增强现实(AR)获得了更多的关注，诸多科技企业对其加大研发力度，希望早日能够开发出在消费者端应用的相关产品。而在AR领域关注度最高的便是AR眼镜，其实现方法一般分为几何光学和衍射光学方案。其中衍射光学方案由于产品更加轻薄透明而备受行业者青睐。衍射光学方案中，表面浮雕光栅(SRG)衍射光波导由于更具量产性，是目前关注度较高的一种方案。
SRG波导光栅主要包括矩形光栅、倾斜光栅和闪耀光栅，其中矩形光栅由于制备工艺难度最低，是目前市场产品中应用最广泛的光栅类型。但相关技术中，SRG波导光栅的光线利用率不高，导致最终进入人眼的图像亮度较低。
发明内容
本公开要解决的技术问题是提供一种光学传输结构及其制作方法、显示装置，能够提高光能利用率。
为解决上述技术问题，本公开的实施例提供技术方案如下：
一方面，提供一种光学传输结构，包括：
光波导；
位于所述光波导的第一表面上的耦入光栅和位于所述光波导的第二表面上的耦出光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
一些实施例中，所述入射光线垂直于所述第一表面入射所述光学传输结构。
一些实施例中，所述入射光线为图像光线。
一些实施例中，所述耦入光栅和所述耦出光栅的光栅周期相同。
一些实施例中，所述耦入光栅和/或所述耦出光栅为矩形光栅，所述矩形光栅的周期为300-600nm。
一些实施例中，所述矩形光栅的高度为30-500nm。
一些实施例中，所述光波导包括：
光波导本体；
设置在所述光波导本体的第二表面上的棱镜部，所述棱镜部包括有凸出于所述光波导本体的所述第一表面。
一些实施例中，所述棱镜部的折射率为n1，所述光波导本体的折射率为n2，所述零级衍射光束入射所述光波导本体的入射角为θ1，折射角为θ2，θ1和θ2满足：
n1sinθ1＝n2sinθ2，其中，θ2≥θc，θc为所述光波导本体的全反射临界角。
一些实施例中，L为所述棱镜部在第一方向上的宽度，所述第一方向与所述第二表面平行且为从所述耦入光栅到所述耦出光栅的方向，S为所述零级衍射光束在所述光波导本体中的传输步长，S＝2dtanθ2，L和S满足：L＜S，其中，d为所述光波导本体的厚度。
一些实施例中，n1的取值范围为1.5～2.0；
n2的取值范围为1.5～2.0。
一些实施例中，n1与n2相等。
一些实施例中，所述光波导包括：
光波导本体，所述光波导本体的入光面与出光面之间成预设角度；其中，所述入光面为所述第一表面，所述出光面为所述第二表面，所述预设角度大于所述光波导本体的全反射临界角。
本公开实施例还提供了一种显示装置，包括如上所述的光学传输结构。
本公开实施例还提供了一种光学传输结构的制作方法，包括：
形成光波导；
在所述光波导的第一表面上形成耦入光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
在位于所述光波导的第二表面上形成耦出光栅；
其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
一些实施例中，形成所述光波导包括：
分别形成光波导本体和棱镜部；
将所述棱镜部贴附在所述光波导本体的第二表面上，使得所述棱镜部的所述第一表面凸出于所述光波导本体。
一些实施例中，形成所述光波导包括：
提供一波导基板；
对所述波导基板进行切削，形成光波导本体和位于所述光波导本体的第二表面上的棱镜部，所述棱镜部包括有凸出于所述光波导本体的所述第一表面。
一些实施例中，所述在所述光波导的第一表面上形成耦入光栅包括：
通过纳米压印方法在柔性基底上制作所述耦入光栅；
将承载有所述耦入光栅的柔性基底贴附在所述第一表面的波导耦入区上。
一些实施例中，在位于所述光波导的第二表面上形成耦出光栅包括：
通过纳米压印方法在柔性基底上制作所述耦出光栅；
将承载有所述耦出光栅的柔性基底贴附在所述第二表面的波导耦出区上。
一些实施例中，形成所述光波导包括：
提供一波导基板；
对所述波导基板进行切削，形成光波导本体，所述光波导本体的入光面与出光面之间成预设角度；其中，所述入光面为所述第一表面，所述出光面为所述第二表面，所述预设角度大于所述光波导本体的全反射临界角。
本公开的实施例具有以下有益效果：
上述方案中，将能量最高的零级衍射光束作为信息传输载体在光波导内全反射传输，能够提升光学传输结构整体的光能利用率。
附图说明
图1为现有矩形光栅衍射效率的分布示意图；
图2和图3为本公开一实施例光学传输结构的光线传播示意图；
图4为本公开另一实施例光学传输结构的光线传播示意图；
图5为本公开一实施例制作光学传输结构的流程示意图；
图6为本公开一实施例在硅基底上制作金属过渡结构的流程示意图；
图7为本公开一实施例制作压印模板的示意图；
图8为本公开一实施例在柔性基底上制作矩形光栅的示意图；
图9为本公开另一实施例制作光学传输结构的流程示意图；
图10为本公开一实施例制作棱镜部以及耦入光栅的流程示意图；
图11为本公开又一实施例中在硅基底上制作金属过渡结构的流程示意图；
图12为本公开又一实施例制作压印模板的示意图；
图13为本公开又一实施例制作光波导本体和耦出光栅的示意图；
图14为本公开又一实施例制作光学传输结构的流程示意图；
图15为本公开再一实施例制作光学传输结构的流程示意图。
附图标记
01 光波导本体03棱镜部
02 矩形光栅
021 耦入光栅
022 耦出光栅
011 波导基板
012 第一过渡结构
013 光波导
04 硅基底
05 金属层
16 光刻胶
051 金属过渡结构
06 压印模板
061 凹槽
07 硬质基板
08 粘结层
09 柔性基底
10 光栅材料层
具体实施方式
为使本公开的实施例要解决的技术问题、技术方案和优点更加清楚，下面将结合附图及具体实施例进行详细描述。
在SRG AR显示中，能量占比最多的包括透射T0级(即零级衍射级次)和透射T±1级衍射级次(即正一级衍射级次和负一级衍射级次)，其中T+1衍射级次是信息传输载体。图1为矩形光栅作耦入光栅和耦出光栅的AR眼镜工作原理示意图，由于矩形光栅为对称结构，T-1和T+1衍射级次衍射效率相等(一般小于20％)，且远低于T0级衍射效率(一般为60％左右)，导致光能利用率不高，最终进入人眼的图像亮度较低。
本公开的实施例提供一种光学传输结构及其制作方法、显示装置，能够提高光能利用率。
本公开的实施例提供一种光学传输结构，包括：
光波导；
位于所述光波导的第一表面上的耦入光栅和位于所述光波导的第二表面 上的耦出光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
本实施例中，将能量最高的零级衍射光束作为信息传输载体在光波导内全反射传输，能够提升光学传输结构整体的光能利用率。
一些实施例中，所述耦入光栅和/或所述耦出光栅为矩形光栅，当然，所述耦入光栅和/或所述耦出光栅并不局限为矩形光栅，还可以为其他类型的光栅，比如闪耀光栅、倾斜光栅等。在所述耦入光栅和/或所述耦出光栅为矩形光栅时，因矩形光栅本征特性导致零级衍射级次(T0级)能量最高(一般≥60％)，远高于T±1衍射级次(T±1衍射效率相同，一般≤20％)，因此，可以提升光效3倍以上。
一具体示例中，如图2和图3所示，光波导包括：光波导本体01；设置在所述光波导本体01的第二表面01a上的棱镜部03，所述棱镜部03包括有凸出于所述光波导本体01的所述第一表面03b，所述棱镜部03的斜面与第二表面01a在同一平面上，从而使得第一表面03b与第二表面01a成预设角度。棱镜部03与光波导本体01可以为一体结构，也可以为两个不同的结构贴合在一起。
如图2和图3所示，耦入光栅021设置在棱镜部03的第一表面03b上的波导耦入区，耦出光栅022设置在光波导本体01的第二表面01a上的波导耦出区，光线入射到波导耦入区的耦入光栅021后发生衍射，经所述耦入光栅021衍射的光线在光波导中传输，在所述光波导中传播的光线入射到设置于所述波导耦出区的耦出光栅022后，经所述耦出光栅022衍射后射出。
棱镜部03的第一表面03b与光波导本体01的第二表面01a之间的夹角为θ1，这样，在入射光线垂直于所述第一表面03b入射所述光学传输结构时，零级衍射光束入射所述光波导本体01的入射角为θ1，折射角为θ2，θ1和θ2满足：
n1sinθ1＝n2sinθ2，其中，θ2≥θc，θc为所述光波导本体的全反射临界角，这 样可以实现零级衍射光束在光波导本体01中全反射传播，其中，所述棱镜部的折射率为n1，所述光波导本体的折射率为n2。为了保证光学传输结构的传输效率，n1的取值范围可以为1.5～2.0；n2的取值范围为1.5～2.0。n1与n2可以相等，也可以不相等。
一些实施例中，如图4所示，光波导包括：光波导本体01；所述光波导本体01的入光面与出光面之间成预设角度；其中，所述入光面为第一表面01b，所述出光面为第二表面01a，所述预设角度θ3大于所述光波导本体01的全反射临界角。
如图4所示，耦入光栅021设置在第一表面01b上的波导耦入区，耦出光栅022设置在光波导本体01的第二表面01a上的波导耦出区，光线入射到波导耦入区的耦入光栅021后发生衍射，经所述耦入光栅021衍射的光线在光波导中传输，在所述光波导中传播的光线入射到设置于所述波导耦出区的耦出光栅022后，经所述耦出光栅022衍射后射出。
光波导本体01的第一表面01b与光波导本体01的第二表面01a之间的夹角为θ3，θ3≥θc，θc为所述光波导本体的全反射临界角，这样，在入射光线垂直于第一表面01b入射所述光学传输结构时，可以实现零级衍射光束在光波导本体01中全反射传播。
一些实施例中，所述入射光线为图像光线，这样光学传输结构可以应用在显示装置比如AR头盔中，通过光学传输结构可以实现图像光线的传输，保证进入人眼的图像的亮度。
一些实施例中，所述耦入光栅021和所述耦出光栅022的光栅周期可以相同，本实施例对此不作限定。
本实施例中，还可以通过设计光栅的高度、占空比等参数得到更高的透射零级衍射效率，进一步提升光学传输结构的整体光效。
一些实施例中，所述耦入光栅和/或所述耦出光栅为矩形光栅，所述矩形光栅的周期可以为300-600nm，比如为300nm、350nm、400nm、450nm、500nm、550nm、600nm，还可以为其他值。不同周期下，光学传输结构的衍射效率不同，在矩形光栅的周期为300-600nm时，可以得到较高的衍射效率。
所述矩形光栅的高度可以为30-500nm，比如为30nm、350nm、400nm、450nm、500nm，还可以为其他值。不同高度下，光学传输结构的衍射效率不同，在矩形光栅的高度为30-500nm时，可以得到较高的衍射效率。
一些实施例中，如图3所示，L为所述棱镜部在第一方向上的宽度，所述第一方向与所述第二表面01a平行且为从所述耦入光栅021到所述耦出光栅022的方向，S为所述零级衍射光束在所述光波导本体01中的传输步长，S＝2dtanθ2，L和S满足：L＜S，其中，d为所述光波导本体01的厚度，这样可以避免棱镜部03在第一方向上的宽度过大，导致零级衍射光束在进入光波导本体01后，仍会再次进入棱镜部03内进行传输，减少了在光波导本体01内传播的零级衍射光束的能量，进而会降低耦出光栅022耦出光线的能量。
本实施例中，d的取值可以为0.1m-5mm，比如为0.5mm、1mm、1.5mm、2mm、2.5mm、3mm、3.5mm、4mm、4.5mm和5mm，还可以为其他值。如果d的取值过大，会使得光学传输结构的厚度过大，不利于光学传输结构的轻薄化；如果光学传输结构的取值过小，会影响光学传输结构的光线传输质量，因此，d的取值优选为0.1m-5mm。
本公开实施例还提供了一种显示装置，包括如上所述的光学传输结构。
该显示装置包括但不限于：射频单元、网络模块、音频输出单元、输入单元、传感器、显示单元、用户输入单元、接口单元、存储器、处理器、以及电源等部件。本领域技术人员可以理解，上述显示装置的结构并不构成对显示装置的限定，显示装置可以包括上述更多或更少的部件，或者组合某些部件，或者不同的部件布置。在本公开实施例中，显示装置包括但不限于显示器、手机、平板电脑、电视机、可穿戴电子设备、导航显示设备等。
具体地，本实施例的显示装置可以为VR显示装置和AR显示装置，比如可以为AR眼镜。
本公开实施例还提供了一种光学传输结构的制作方法，包括：
形成光波导；
在所述光波导的第一表面上形成耦入光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
在位于所述光波导的第二表面上形成耦出光栅；
其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
本实施例中，将能量最高的零级衍射光束作为信息传输载体在光波导内全反射传输，能够提升光学传输结构整体的光能利用率。
一些实施例中，所述耦入光栅和/或所述耦出光栅为矩形光栅，当然，所述耦入光栅和/或所述耦出光栅并不局限为矩形光栅，还可以为其他类型的光栅，比如闪耀光栅、倾斜光栅等。在所述耦入光栅和/或所述耦出光栅为矩形光栅时，因矩形光栅本征特性导致零级衍射级次(T0级)能量最高(一般≥60％)，远高于T±1衍射级次(T±1衍射效率相同，一般≤20％)，因此，可以提升光效3倍以上。
一具体示例中，如图2和图3所示，光波导包括：光波导本体01；设置在所述光波导本体01的第二表面01a上的棱镜部03，所述棱镜部03包括有凸出于所述光波导本体01的所述第一表面03b，所述棱镜部03的斜面与第二表面01a在同一平面上，从而使得第一表面03b与第二表面01a成预设角度。棱镜部03与光波导本体01可以为一体结构，也可以为两个不同的结构贴合在一起。
如图2和图3所示，耦入光栅021设置在棱镜部03的第一表面03b上的波导耦入区，耦出光栅022设置在光波导本体01的第二表面01a上的波导耦出区，光线入射到波导耦入区的耦入光栅021后发生衍射，经所述耦入光栅021衍射的光线在光波导中传输，在所述光波导中传播的光线入射到设置于所述波导耦出区的耦出光栅022后，经所述耦出光栅022衍射后射出。
棱镜部03的第一表面03b与光波导本体01的第二表面01a之间的夹角为θ1，这样，在入射光线垂直于所述第一表面03b入射所述光学传输结构时，零级衍射光束入射所述光波导本体01的入射角为θ1，折射角为θ2，θ1和θ2满足：
n1sinθ1＝n2sinθ2，其中，θ2≥θc，θc为所述光波导本体的全反射临界角，这 样可以实现零级衍射光束在光波导本体01中全反射传播，其中，所述棱镜部的折射率为n1，所述光波导本体的折射率为n2。为了保证光学传输结构的传输效率，n1的取值范围可以为1.5～2.0；n2的取值范围为1.5～2.0。n1与n2可以相等，也可以不相等。
一些实施例中，如图4所示，光波导包括：光波导本体01；所述光波导本体01的入光面与出光面之间成预设角度；其中，所述入光面为第一表面01b，所述出光面为第二表面01a，所述预设角度θ3大于所述光波导本体01的全反射临界角。
如图4所示，耦入光栅021设置在第一表面01b上的波导耦入区，耦出光栅022设置在光波导本体01的第二表面01a上的波导耦出区，光线入射到波导耦入区的耦入光栅021后发生衍射，经所述耦入光栅021衍射的光线在光波导中传输，在所述光波导中传播的光线入射到设置于所述波导耦出区的耦出光栅022后，经所述耦出光栅022衍射后射出。
光波导本体01的第一表面01b与光波导本体01的第二表面01a之间的夹角为θ3，θ3≥θc，θc为所述光波导本体的全反射临界角，这样，在入射光线垂直于第一表面01b入射所述光学传输结构时，可以实现零级衍射光束在光波导本体01中全反射传播。
一些实施例中，如图3所示，L为所述棱镜部在第一方向上的宽度，所述第一方向与所述第二表面01a平行且为从所述耦入光栅021到所述耦出光栅022的方向，S为所述零级衍射光束在所述光波导本体01中的传输步长，S＝2dtanθ2，L和S满足：L＜S，其中，d为所述光波导本体01的厚度，这样可以避免棱镜部03在第一方向上的宽度过大，导致零级衍射光束在进入光波导本体01后，仍会再次进入棱镜部03内进行传输，减少了在光波导本体01内传播的零级衍射光束的能量，进而会降低耦出光栅022耦出光线的能量。
下面结合图4-图15以及具体的实施例对本公开的光学传输结构进行进一步介绍。
一些实施例中，如图4所示，可以提供一厚度合适的波导基板；对所述波导基板进行切削，形成光波导本体01，所述光波导本体的入光面与出光面 之间成预设角度；其中，所述入光面为所述第一表面01b，所述出光面为所述第二表面01a，所述预设角度大于所述光波导本体01的全反射临界角。一些实施例中，在光波导本体01和棱镜部03的折射率相等时，可以提供一厚度合适的波导基板；对所述波导基板进行切削，形成光波导本体和位于所述光波导本体的第二表面上的棱镜部，所述棱镜部包括有凸出于所述光波导本体的所述第一表面。
具体地，如图5a所示，选取厚度合适的波导材料作为波导基板011；如图5b所示，利用金刚石切削或激光切割等手段将波导基板011切割出第一过渡结构012，第一过渡结构012为光波导本体和棱镜部组成的整体；如图5c所示，通过切割磨削手段在第一过渡结构012上制备耦出光栅022；如图5d所示，通过切割磨削手段在第一过渡结构012上制备耦入光栅021，即可得到本实施例的光学传输结构。
一些实施例中，在光波导本体的折射率与棱镜部的折射率相等时，还可以通过贴合工艺形成光学传输结构。形成所述光波导包括：分别形成光波导本体和棱镜部；将所述棱镜部贴附在所述光波导本体的第二表面上，使得所述棱镜部的所述第一表面凸出于所述光波导本体。然后，通过纳米压印方法在柔性基底上制作所述耦入光栅；将承载有所述耦入光栅的柔性基底贴附在所述第一表面的波导耦入区上。通过纳米压印方法在柔性基底上制作所述耦出光栅；将承载有所述耦出光栅的柔性基底贴附在所述第二表面的波导耦出区上。
具体地，如图6a所示，在硅基底04上形成金属层05和光刻胶16，其中，金属层05可以采用Mo；如图6b所示，对光刻胶16进行曝光显影，形成光刻胶16的图形；如图6c所示，以光刻胶16的图形为掩膜，对金属层05进行刻蚀，形成金属过渡结构051。
之后，如图7a和图7b所示，在形成有金属过渡结构051的硅基底04上形成紫外光胶，对紫外光胶进行固化后形成压印模板06；如图7c所示，去除形成有金属过渡结构051的硅基底04，得到形成有凹槽061的压印模板06，其中，凹槽061的形状与金属过渡结构051的形状匹配。
之后，如图8a所示，在硬质基板07上形成粘结层08、柔性基底09和光栅材料层10，其中，硬质基板07可以采用石英基板或玻璃基板，柔性基底09可以采用聚酰亚胺薄膜，光栅材料层10可以采用压印胶；如图8b所示，将形成有凹槽061的压印模板06按压在光栅材料层10上；如图8c所示，去除形成有凹槽061的压印模板06后，光栅材料层10形成为与凹槽061的形状匹配的矩形光栅02；如图8d所示，采用激光剥离的方式去除硬质基板07和粘结层08，得到承载有矩形光栅02的柔性基底09。
然后，如图9a所示，选取厚度合适的波导材料作为波导基板011；如图9b所示，利用金刚石切削或激光切割等手段将波导基板011切割出第一过渡结构012，第一过渡结构012为光波导本体和棱镜部组成的整体；如图9c所示，将具备不同光栅参数的矩形光栅02通过贴合工艺贴附在波导耦入区和波导耦出区，即可得到本实施例的光学传输结构。
一些实施例中，在光波导本体的折射率与棱镜部的折射率不相等时，可以通过贴合工艺形成光学传输结构。
具体地，如图6a所示，在硅基底04上形成金属层05和光刻胶16，其中，金属层05可以采用Mo；如图6b所示，对光刻胶16进行曝光显影，形成光刻胶16的图形；如图6c所示，以光刻胶16的图形为掩膜，对金属层05进行刻蚀，形成金属过渡结构051。
之后，如图7a和图7b所示，在形成有金属过渡结构051的硅基底04上形成紫外光胶，对紫外光胶进行固化后形成压印模板06；如图7c所示，去除形成有金属过渡结构051的硅基底04，得到形成有凹槽061的压印模板06，其中，凹槽061的形状与金属过渡结构051的形状匹配。
之后，如图10a所示，在硬质基板07上形成光栅材料层10，其中，硬质基板07可以采用石英基板或玻璃基板，光栅材料层10可以采用压印胶；如图10b所示，将形成有凹槽061的压印模板06按压在光栅材料层10上；如图10c所示，去除形成有凹槽061的压印模板06后，光栅材料层10形成为与凹槽061的形状匹配的耦入光栅021；如图10d所示，对形成有耦入光栅021的硬质基板07进行激光切割，得到棱镜部03和耦入光栅021。
之后，如图11a所示，在硅基底04上形成金属层05和光刻胶16，其中，金属层05可以采用Mo；如图11b所示，对光刻胶16进行曝光显影，形成光刻胶16的图形；如图11c所示，以光刻胶16的图形为掩膜，对金属层05进行刻蚀，形成金属过渡结构051。
之后，如图12a和图12b所示，在形成有金属过渡结构051的硅基底04上形成紫外光胶，对紫外光胶进行固化后形成压印模板06；如图12c所示，去除形成有金属过渡结构051的硅基底04，得到形成有凹槽061的压印模板06，其中，凹槽061的形状与金属过渡结构051的形状匹配。
之后，如图13a所示，形成光波导本体01和光栅材料层10；如图13b所示，将形成有凹槽061的压印模板06按压在光栅材料层10上；如图13c所示，去除形成有凹槽061的压印模板06后，光栅材料层10形成为与凹槽061的形状匹配的耦出光栅022。
之后，如图14所示，将形成有耦入光栅021的棱镜部03通过粘合胶与形成有耦出光栅022的光波导本体01贴合为一体，即可得到本实施例的光学传输结构。
一些实施例中，在光波导本体的折射率与棱镜部的折射率不相等时，可以通过切割工艺形成光学传输结构。
具体地，如图6a所示，在硅基底04上形成金属层05和光刻胶16，其中，金属层05可以采用Mo；如图6b所示，对光刻胶16进行曝光显影，形成光刻胶16的图形；如图6c所示，以光刻胶16的图形为掩膜，对金属层05进行刻蚀，形成金属过渡结构051。
之后，如图7a和图7b所示，在形成有金属过渡结构051的硅基底04上形成紫外光胶，对紫外光胶进行固化后形成压印模板06；如图7c所示，去除形成有金属过渡结构051的硅基底04，得到形成有凹槽061的压印模板06，其中，凹槽061的形状与金属过渡结构051的形状匹配。
之后，如图8a所示，在硬质基板07上形成粘结层08、柔性基底09和光栅材料层10，其中，硬质基板07可以采用石英基板或玻璃基板，柔性基底09可以采用聚酰亚胺薄膜，光栅材料层10可以采用压印胶；如图8b所示， 将形成有凹槽061的压印模板06按压在光栅材料层10上；如图8c所示，去除形成有凹槽061的压印模板06后，光栅材料层10形成为与凹槽061的形状匹配的矩形光栅02；如图8d所示，采用激光剥离的方式去除硬质基板07和粘结层08，得到承载有矩形光栅02的柔性基底09。
如图15a所示，提供硬质基板07，硬质基板07可以采用石英基板或玻璃基板，对硬质基板07进行切割，得到多个棱镜部03；如图15b所示，将棱镜部03通过粘合胶与光波导本体01贴合为一体；如图15c所示，将具备不同光栅参数的矩形光栅02通过贴合工艺贴附在棱镜部03的波导耦入区和光波导本体01的波导耦出区，即可得到如图15d所示的本实施例的光学传输结构。
本实施例利用矩形光栅衍射效率最高的透射零级衍射光束作为信息传输载体，而非惯用的透射一级衍射光束，从而可以大幅提升光学传输结构的整体光效。
在本公开各方法实施例中，所述各步骤的序号并不能用于限定各步骤的先后顺序，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，对各步骤的先后变化也在本公开的保护范围之内。
需要说明，本说明书中的各个实施例均采用递进的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于实施例而言，由于其基本相似于产品实施例，所以描述得比较简单，相关之处参见产品实施例的部分说明即可。
除非另外定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的组成部分。“包括”或者“包含”等类似的词语意指出现该词前面的元件或者物件涵盖出现在该词后面列举的元件或者物件及其等同，而不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电性的连接，不管是直接的还是间接的。“上”、“下”、“左”、“右”等仅用于表示相对位置关系，当被描述对象的绝对位置改变后，则该相 对位置关系也可能相应地改变。
可以理解，当诸如层、膜、区域或基板之类的元件被称作位于另一元件“上”或“下”时，该元件可以“直接”位于另一元件“上”或“下”，或者可以存在中间元件。
在上述实施方式的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应以所述权利要求的保护范围为准。

Claims (19)

  1. 一种光学传输结构，其特征在于，包括：
    光波导；
    位于所述光波导的第一表面上的耦入光栅和位于所述光波导的第二表面上的耦出光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
    其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
  2. 根据权利要求1所述的光学传输结构，其特征在于，所述入射光线垂直于所述第一表面入射所述光学传输结构。
  3. 根据权利要求1所述的光学传输结构，其特征在于，所述入射光线为图像光线。
  4. 根据权利要求1所述的光学传输结构，其特征在于，所述耦入光栅和所述耦出光栅的光栅周期相同。
  5. 根据权利要求1所述的光学传输结构，其特征在于，所述耦入光栅和/或所述耦出光栅为矩形光栅，所述矩形光栅的周期为300-600nm。
  6. 根据权利要求5所述的光学传输结构，其特征在于，所述矩形光栅的高度为30-500nm。
  7. 根据权利要求1所述的光学传输结构，其特征在于，所述光波导包括：
    光波导本体；
    设置在所述光波导本体的第二表面上的棱镜部，所述棱镜部包括有凸出于所述光波导本体的所述第一表面。
  8. 根据权利要求7所述的光学传输结构，其特征在于，所述棱镜部的折射率为n1，所述光波导本体的折射率为n2，所述零级衍射光束入射所述光波导本体的入射角为θ1，折射角为θ2，θ1和θ2满足：
    n1sinθ1＝n2sinθ2，其中，θ2≥θc，θc为所述光波导本体的全反射临界角。
  9. 根据权利要求8所述的光学传输结构，其特征在于，L为所述棱镜部 在第一方向上的宽度，所述第一方向与所述第二表面平行且为从所述耦入光栅到所述耦出光栅的方向，S为所述零级衍射光束在所述光波导本体中的传输步长，S＝2dtanθ2，L和S满足：L＜S，其中，d为所述光波导本体的厚度。
  10. 根据权利要求8所述的光学传输结构，其特征在于，n1的取值范围为1.5～2.0；
    n2的取值范围为1.5～2.0。
  11. 根据权利要求8所述的光学传输结构，其特征在于，n1与n2相等。
  12. 根据权利要求1所述的光学传输结构，其特征在于，所述光波导包括：
    光波导本体，所述光波导本体的入光面与出光面之间成预设角度；其中，所述入光面为所述第一表面，所述出光面为所述第二表面，所述预设角度大于所述光波导本体的全反射临界角。
  13. 一种显示装置，其特征在于，包括如权利要求1-12中任一项所述的光学传输结构。
  14. 一种光学传输结构的制作方法，其特征在于，包括：
    形成光波导；
    在所述光波导的第一表面上形成耦入光栅，所述耦入光栅用于将入射光线耦入所述光波导中；
    在位于所述光波导的第二表面上形成耦出光栅；
    其中，所述第一表面与所述第二表面之间成预设角度，使得经所述耦入光栅传输到所述光波导内的零级衍射光束在所述光波导内产生全反射，所述耦出光栅用于将出射光线耦出所述光波导。
  15. 根据权利要求14所述的光学传输结构的制作方法，其特征在于，形成所述光波导包括：
    分别形成光波导本体和棱镜部；
    将所述棱镜部贴附在所述光波导本体的第二表面上，使得所述棱镜部的所述第一表面凸出于所述光波导本体。
  16. 根据权利要求14所述的光学传输结构的制作方法，其特征在于，形 成所述光波导包括：
    提供一波导基板；
    对所述波导基板进行切削，形成光波导本体和位于所述光波导本体的第二表面上的棱镜部，所述棱镜部包括有凸出于所述光波导本体的所述第一表面。
  17. 根据权利要求14所述的光学传输结构的制作方法，其特征在于，所述在所述光波导的第一表面上形成耦入光栅包括：
    通过纳米压印方法在柔性基底上制作所述耦入光栅；
    将承载有所述耦入光栅的柔性基底贴附在所述第一表面的波导耦入区上。
  18. 根据权利要求14所述的光学传输结构的制作方法，其特征在于，在位于所述光波导的第二表面上形成耦出光栅包括：
    通过纳米压印方法在柔性基底上制作所述耦出光栅；
    将承载有所述耦出光栅的柔性基底贴附在所述第二表面的波导耦出区上。
  19. 根据权利要求14所述的光学传输结构的制作方法，其特征在于，形成所述光波导包括：
    提供一波导基板；
    对所述波导基板进行切削，形成光波导本体，所述光波导本体的入光面与出光面之间成预设角度；其中，所述入光面为所述第一表面，所述出光面为所述第二表面，所述预设角度大于所述光波导本体的全反射临界角。
PCT/CN2023/121893 2022-11-16 2023-09-27 光学传输结构及其制作方法、显示装置 WO2024103978A1 (zh)

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