Silver ink flow control by inkjet removable mask for augmented reality devices

Abstract

A method and apparatus for forming a device includes depositing a mask layer on a first portion of a surface, the mask layer forming a feature on the surface, depositing a mirror layer within the feature on a second portion of the surface, and removing the mask layer from the surface.

Description

Background Technical Field

[0002] Embodiments of the present disclosure generally relate to waveguides and methods for manufacturing waveguides.

[0003] Description of Related Art

[0004] In waveguide devices such as virtual reality (VR) devices or augmented reality (AR) devices, waveguide combiners are often used to couple virtual images, transmit light inside a glass substrate by total internal reflection, and then couple the image when the image reaches the position of the viewer's eyes. For optical coupling and decoupling, the tilted features and grooves in the waveguide combiner are typically used as gratings for light diffraction. The orientation of the lines (fins) controls the propagation direction of light, while the tilt angle controls the efficiency of the desired diffraction order. Mirrors are used to reflect light in a controlled manner.

[0005] In many applications, mirrors with silver layers are used in such waveguide devices. To prevent long-term oxidation of silver, an encapsulation layer is often deposited on or above the silver layer. However, when the silver layer is exposed to an oxidizing environment, such as oxygen in a plasma reactor, silver atoms often migrate into adjacent layers and / or the substrate, thereby damaging the waveguide device. Migration is especially a problem for silicon oxide layers and glass or quartz substrates or wafers.

[0006] Therefore, improved waveguides and methods for manufacturing waveguides are needed. Summary of the Invention

[0007] The present disclosure generally relates to a method for forming a device. The method may include depositing a mask layer on a first portion of a surface, the mask layer forming a feature on the surface. The method may include depositing a mirror layer on a second portion of the surface within the feature. The method may include removing the mask layer from the surface.

[0008] The present disclosure generally relates to a mask layer. The mask layer may include a composition disposed on a portion of a surface, the composition capable of forming a feature on the surface. In one example, the composition may include an organic polymer, a photocurable component, a solvent, and an additive.

[0009] The present disclosure generally relates to a device. The device may include a mask layer deposited on a first portion of a surface, the mask layer forming a feature on the surface, and a mirror layer deposited on a second portion of the surface within the feature. Brief Description of the Drawings

[0010] In order to understand in detail the manner of the above-described features of the present disclosure, a more specific description of the present disclosure, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the drawings. It should be noted, however, that the drawings only illustrate exemplary embodiments and are not to be considered as limiting its scope, and other equally effective embodiments are allowed.

[0011] Figure 1A A perspective front view of a waveguide according to one or more embodiments described and discussed herein is depicted.

[0012] Figure 1B A schematic cross-sectional view of a waveguide device according to one or more embodiments described and discussed herein is depicted.

[0013] Figure 1C A schematic cross-sectional view of a waveguide device according to one or more embodiments described and discussed herein is depicted.

[0014] Figure 2 A flowchart of a method for forming a waveguide is depicted.

[0015] Figures 3A - 3G A schematic cross-sectional view of a waveguide according to one or more embodiments described and discussed herein is depicted.

[0016] For ease of understanding, where possible, the same reference numerals have been used to denote the same elements as in the drawings. It is contemplated that the elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. Detailed Description

[0017] Embodiments of the present disclosure generally relate to packaged waveguides and methods for manufacturing packaged waveguides. The waveguides can be used in virtual reality (VR) devices, augmented reality (AR) devices, and other devices, including optical devices, display devices, and / or microelectronic components.

[0018] Figure 1Ais a perspective front view of waveguide 100. It should be understood that the waveguide 100 described herein is an exemplary waveguide, and other waveguides may be used or modified in conjunction with aspects of the present disclosure to accomplish aspects of the present disclosure. Waveguide 100 includes a plurality of structures 102. Structures 102 may be disposed above, below, or on the first surface 103 of substrate 101, or disposed within substrate 101. Structures 102 are nanostructures having sub-micron critical dimensions (e.g., width less than 1 micron). Regions of structures 102 correspond to one or more gratings 104. In one embodiment that may be combined with other embodiments described herein, waveguide 100 includes at least a first grating 104a corresponding to an input coupling grating and a third grating 104c corresponding to an output coupling grating. In another embodiment that may be combined with other embodiments described herein, waveguide 100 further includes a second grating 104b. Second grating 104b corresponds to a pupil expansion grating or a folding grating. Cutline 106 is superimposed on Figure 1A the view of waveguide 100 in Figure 1B and Figure 1C a cross-sectional view.

[0019] Figure 1B is a cross-sectional view of one embodiment of a waveguide that may correspond to Figure 1A cutline 106. Cutline 106 corresponds to a grating 104 such as first grating 104a. The embodiments described herein may be applied to first grating 104a of an input coupler grating, second grating 104b of a pupil expansion grating, third grating 104c of an output coupler grating, or a combination thereof. Figure 1B Waveguide 100 of Figure 2 includes structures 102 of substrate 101. In some embodiments, structures 102 may be disposed above, below, or on the first surface 103 of substrate 101, or disposed within substrate 101. As Figure 1B shown, structures 102 are disposed on first surface 103. Figure 1B Waveguide 100 of Figure 1BThe waveguide 100 optionally includes a packaging layer 110. The packaging layer 110 can be disposed on the mirror layer 108, such that the packaging layer 110 is disposed on the bottom surface 116 and each side surface 118 of the mirror layer 108. The packaging layer 110 can extend from the mirror layer 108 to be disposed on a portion of the bottom surface 114 of the substrate 101.

[0020] Figure 1C is a cross-sectional view of an embodiment of the waveguide 100. The cross-sectional view can correspond to Figure 1A the cutting line 106. The cutting line 106 corresponds to a grating 104 such as the first grating 104a. The embodiments described herein can be applied to the first grating 104a of the input coupler grating, the second grating 104b of the pupil expansion grating, the third grating 104c of the output coupler grating, or a combination thereof. Figure 1C The waveguide 100 includes a structure 102 disposed on the first surface 103 of the substrate 101. The mirror layer 108 is located on an adjacent region 111 of the second surface 114 adjacent to the structure 102 of the grating 104. The regions 113 of the surface surrounding the adjacent region 111 and the grating 104 do not include the mirror layer 108. That is, the mirror layer 108 is only located on the adjacent region 111 and the opposite region 115 of the grating 104. Figure 1C The waveguide 100 includes a mirror layer 108 disposed above the substrate 101, on the top first surface 103 of the substrate 101. The mirror layer can be disposed opposite the optical engine 112 across the substrate 101. In some cases, Figure 1C The waveguide 100 optionally includes a packaging layer 110. The packaging layer 110 can be disposed on the mirror layer 108 such that the packaging layer 110 is disposed on the top surface 120 and each side surface 118 of the mirror layer 108. The packaging layer 110 can extend from the mirror layer 108 to be disposed on a portion of the top first surface 103 of the substrate 101.

[0021] Figure 2 Depicts a flowchart of a method 200 for forming a waveguide (e.g., waveguide 100, waveguide 300) according to one or more embodiments of the present disclosure. Figures 3A - 3G Shows a cross-sectional schematic view of the waveguide 300 during the method 200 according to one or more embodiments of the present disclosure. It should be understood that Figures 3A - 3G only shows a partial schematic view of the waveguide 300, and the waveguide can contain any number of features and additional materials having the aspects shown in the figure. It should also be noted that although Figure 2 the method 200 shown is described sequentially, other process sequences including one or more operations that have been omitted and / or added and / or have been rearranged in another desired order are within the scope of the disclosed embodiments provided herein. In some embodiments, the waveguide 100 can be referred to for understanding Figures 3A - 3GWaveguide 300. In other embodiments, waveguide 300 can be understood independently of waveguide 100.

[0022] Figure 3A Illustrates waveguide 300 at operation 202. At operation 202, as Figure 3A shown. Mask layer 302 is deposited on substrate 101. In some embodiments, mask layer 302 is deposited only on some portions 320 of the substrate. In some embodiments, mask layer 302 can be deposited by an inkjet deposition process at operation 202. The inkjet deposition process can have a viscosity of about 1 cP or higher to about 100 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower. In some embodiments, mask layer 302 can be deposited by a screen printing deposition process at operation 202. The inkjet deposition process can have a viscosity of about 10 cP or higher to about 100,00 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower.

[0023] In some embodiments, mask layer 302 can be a water-soluble mask. The water-soluble mask can include a polymer component, a photocurable component, a solvent, and an additive. The polymer component of the water-soluble solution includes, but is not limited to, polyvinylpyrrolidone (PVP), polyvinylpyrrolidone - co - polyvinyl alcohol, polypropylene glycol, partially hydrolyzed polyvinyl acetate, or combinations thereof.

[0024] The photocurable component includes, but is not limited to, monomers, crosslinkers, oligomers, photoinitiators, or combinations thereof. The monomers include, but are not limited to, water-soluble (meth)acrylates, epoxy resins, or combinations thereof. The crosslinkers include, but are not limited to, water-soluble polyfunctional (meth)acrylates or epoxy resins, or combinations thereof. The oligomers include, but are not limited to, water-soluble (meth)acrylates, epoxy-functionalized oligomers, or combinations thereof. The photoinitiators include, but are not limited to, photoinitiators that can generate free radicals and / or protons upon exposure to UV and / or visible light.

[0025] A solvent for a water-soluble mask that can be diluted and then evaporated during baking. The solvent can include, but is not limited to, any organic solvent based on esters, ethers, and alcohols that has a boiling point below about 250 °C or higher to about 350 °C or lower, such as about 300 °C, at about 0.5 atm or higher to about 1.5 atm or lower, such as 1 atm. The solvent can include, but is not limited to, any mixture of an organic solvent and H2O, such as a mixture with an H2O content ranging from about 0% to about 80%. Such organic solvents can include, but are not limited to, DPGME (34590-94-8), DPGBE (29911-28-2), TPGME (25498-49-1), DPGPE (29911-27-1), DPGDME (111109-77-4), TPGBE (55934-93-5), PGBE (5131-66-8), DEGME (111-77-3), DEGEE (111-90-0), TEGME (112-35-6), PGME (107-98-2), PGPE (1569-1-3), PGMEA (108-65-6), DPGMEA (88917-22-0), ethanol (64-17-5), methanol (67-56-1), isopropanol (67-63-0), 1-butanol (71-36-3), 2-butanol (78-92-2), 1-pentanol (71-41-0), 2-pentanol (6032-29-7), 3-pentanol (584-2-1), 1-hexanol (111-27-3), 2-hexanol (626-93-7), 3-hexanol (623-37-0), butyl acetate (123-86-4), butyl lactate (138-22-7), or combinations thereof.

[0026] The additives include surfactants, polymers, or combinations thereof. The surfactant can tune the surface tension. The polymer can tune the viscosity of the formulation.

[0027] In some embodiments, the mask layer 302 can be an ashing mask. The ashing mask includes, but is not limited to, epoxy resins, polystyrene, PMMA, phenolic resins, PVP, or combinations thereof.

[0028] The photocurable component includes, but is not limited to, monomers, crosslinkers, oligomers, photoinitiators, or combinations thereof. The monomers include, but are not limited to, water-soluble (meth)acrylates, epoxy resins, or combinations thereof. The crosslinkers include, but are not limited to, water-soluble polyfunctional (meth)acrylates or epoxy resins, or combinations thereof. The oligomers include, but are not limited to, water-soluble (meth)acrylates, epoxy-functionalized oligomers, or combinations thereof. The photoinitiators include, but are not limited to, photoinitiators that can generate free radicals and / or protons upon exposure to UV and / or visible light.

[0029] A solvent for a water-soluble mask that can be diluted and then evaporated during baking. The solvent can include, but is not limited to, any organic solvent based on esters, ethers, and alcohols that has a boiling point below about 250 °C or higher to about 350 °C or lower, such as about 300 °C, at about 0.5 atm or higher to about 1.5 atm or lower, such as 1 atm. The solvent can include, but is not limited to, any mixture of an organic solvent and H2O, such as a mixture with an H2O content ranging from about 0% to about 80%. Such organic solvents can include, but are not limited to, DPGME (34590-94-8), DPGBE (29911-28-2), TPGME (25498-49-1), DPGPE (29911-27-1), DPGDME (111109-77-4), TPGBE (55934-93-5), PGBE (5131-66-8), DEGME (111-77-3), DEGEE (111-90-0), TEGME (112-35-6), PGME (107-98-2), PGPE (1569-1-3), PGMEA (108-65-6), DPGMEA (88917-22-0), ethanol (64-17-5), methanol (67-56-1), isopropyl alcohol (67-63-0), 1-butanol (71-36-3), 2-butanol (78-92-2), 1-pentanol (71-41-0), 2-pentanol (6032-29-7), 3-pentanol (584-2-1), 1-hexanol (111-27-3), 2-hexanol (626-93-7), 3-hexanol (623-37-0), butyl acetate (123-86-4), butyl lactate (138-22-7), or combinations thereof.

[0030] Additives include surfactants, polymers, or combinations thereof. Surfactants can tune surface tension. Polymers can tune the viscosity of the formulation.

[0031] In some embodiments, the mask layer 302 material can be modifiable such that the surface tension, viscosity, and air pressure of the system can be tuned to suit certain use cases.

[0032] Figure 3B The waveguide 300 at operation 204 is depicted. At operation 204, as Figure 3B shown, the mask layer 302 is then cured to form trench features 322 on the surface of the substrate 101. In some embodiments, the mask layer 302 can be cured using a thermal curing or ultraviolet curing process. In some embodiments, the structure 102 can be formed under the substrate 101, opposite the mask layer 302. In other embodiments not shown, the structure 102 can be formed above the substrate 101 and above the mask layer 302.

[0033] Implementing the mask layer 302 on the portion 320 of the substrate allows the deposition of the mirror layer 108 at operation 206, as shown in Figure 2 the waveguide 300 of Figure 3C and Figure 3D . Specifically, the mask layer 302 allows the mirror layer 108 to be deposited within the trench feature 322 and along the desired deposition edge limit 330. The mask layer 302 achieves this by preventing the mirror layer 108 from extending beyond the desired deposition edge limit 330 during the initial deposition (as shown in Figure 3C ) and optional reflow (as shown in Figure 3D ). In fact, the mask layer 302 can act as a wall to limit the reflow of the mirror layer 108 material.

[0034] In some embodiments, the mirror layer 108 material can include silver (Ag). In some embodiments, the mirror layer 108 can be deposited at operation 206 by an inkjet deposition process. The inkjet deposition process can have a viscosity of about 1 cP or higher to about 100 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower. In some embodiments, the mirror layer 108 can be deposited at operation 202 by a screen printing deposition process. The inkjet deposition process can have a viscosity of about 10 cP or higher to about 100,00 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower. In some embodiments, the mirror layer 108 can be disposed above or opposite the first grating 104a corresponding to the input coupling grating, as shown in Figure 1A . In some embodiments, the mirror layer 108 can have a width of about 1 μm. In some embodiments, the mirror layer 108 can have a height of about 20 nm or greater to about 20 μm or lower, such as about 5 μm or greater to about 10 μm or lower. In some embodiments, the thickness of the mirror layer 108 can be substantially uniform, substantially non-uniform, or substantially semi-uniform in the lateral direction.

[0035] Figure 3E The waveguide 300 at operation 208 is depicted. In some embodiments, the mirror layer 108 can be cured using a thermal curing or ultraviolet curing process. In some embodiments, the structure 102 can be formed below the substrate 101, opposite the mirror layer 108. In other embodiments not shown, the structure 102 can be formed above the substrate 101, above the mirror layer 108.

[0036] Figure 3FIllustrates waveguide 300 at operation 210. At operation 210, mask layer 302 is removed from the surface of substrate 101. In some embodiments, mask layer 302 can be removed using a cleanable process, where mask layer 302 is water-soluble and dissolves when substrate 101 is exposed to an aqueous solution. In some embodiments, mask layer 302 can be removed using an ashing process (e.g., a plasma ashing process), where mask layer 302 is etched away due to exposure of the entity to radical species.

[0037] Figure 3G Illustrates waveguide 300 at optional operation 212. At operation 210, encapsulation layer 110 is deposited on mirror layer 108. Encapsulation layer 110 can be positioned on mirror layer 108 in a manner similar to Figure 1B and Figure 1C the deposition of encapsulation layer 110 described in. In some embodiments, encapsulation layer 110 can be deposited at operation 212 by an inkjet deposition process. The inkjet deposition process can have a viscosity of about 1 cP or higher to about 100 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower. In some embodiments, mask layer 302 can be deposited at operation 202 by a screen printing deposition process. The inkjet deposition process can have a viscosity of about 10 cP or higher to about 100,00 cP or lower, and a surface tension of about 20 mN / m or higher to about 60 mN / m or lower.

[0038] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure can be designed without departing from its basic scope, and its scope is determined by the claims that follow.

Claims

1. A method for forming a device, the method comprising: Depositing a mask layer on a first portion of a surface, the mask layer forming a feature on the surface; Depositing a mirror layer on a second portion of the surface within the feature; And Removing the mask layer from the surface.

2. The method according to claim 1, the method further comprising: Curing the mask layer using thermal radiation or ultraviolet radiation; And Curing the mirror layer using thermal radiation or ultraviolet radiation.

3. The method according to claim 1, wherein the method further comprises: Reflowing the mirror layer on the second portion of the surface.

4. The method according to claim 1, wherein depositing the mask layer on the first portion of the surface comprises: Depositing the mask layer using an inkjet deposition process or a screen printing deposition process.

5. The method according to claim 1, wherein depositing the mirror layer on the second portion of the surface comprises: Depositing the mirror layer using an inkjet deposition process or a screen printing deposition process.

6. The method according to claim 1, wherein removing the mask layer comprises: Dissolving the mask layer in an aqueous solution or etching the mask layer using free radical species.

7. The method according to claim 1, wherein the mirror layer comprises at least one silver (Ag) material.

8. The method according to claim 1, wherein the surface is disposed away from the light engine.

9. A mask layer, the mask layer comprising: A composition disposed on a portion of a surface, the composition capable of forming a feature on the surface, the composition comprising: An organic polymer; A photocurable component; A solvent; and An additive.

10. The mask layer according to claim 9, wherein the composition is water-soluble.

11. The mask layer according to claim 10, wherein the organic polymer comprises at least one of the following: Polyvinylpyrrolidone (PVP), a copolymer of PVP, a block copolymer, a random or alternating copolymer, polyvinylpyrrolidone - copolyvinyl alcohol, or copovidone.

12. The mask layer according to claim 9, wherein the composition is ashing-capable.

13. The mask layer according to claim 12, wherein the organic polymer comprises at least one of: Epoxy resin, a derivative of the epoxy resin, polystyrene, a derivative of the polystyrene, polymethyl methacrylate (PMMA), a derivative of the PMMA, phenolic resin, a derivative of the phenolic resin, or polyvinylpyrrolidone (PVP).

14. The mask layer according to claim 9, wherein the photocurable component comprises at least one of the following: Monomer, water-soluble (meth)acrylate, epoxy resin, crosslinking agent, water-soluble polyfunctional (meth)acrylate, oligomer, functionalized polymer, or photoinitiator.

15. The mask layer according to claim 9, wherein the solvent comprises at least one of the following: DPGME (34590-94-8), DPGBE (29911-28-2), TPGME (25498-49-1), DPGPE (29911-27-1), DPGDME (111109-77-4), TPGBE (55934-93-5), PGBE (5131-66-8), DEGME (111-77-3), DEGEE (111-90-0), TEGME (112-35-6), PGME (107-98-2), PGPE (1569-1-3), PGMEA (108-65-6), DPGMEA (88917-22-0), ethanol (64-17-5), methanol (67-56-1), isopropanol (67-63-0), 1-butanol (71-36-3), 2-butanol (78-92-2), 1-pentanol (71-41-0), 2-pentanol (6032-29-7), 3-pentanol (584-2-1), 1-hexanol (111-27-3), 2-hexanol (626-93-7), 3-hexanol (623-37-0), butyl acetate (123-86-4) or butyl lactate (138-22-7).

16. The mask layer according to claim 9, wherein the additive comprises at least one of the following: a surfactant capable of tuning the surface tension value of the composition; and a polymer capable of tuning the viscosity value of the composition.

17. An apparatus, the apparatus comprising: a mask layer deposited on a first portion of a surface, the mask layer forming features on the surface; and the mirror layer deposited on a second portion of the surface within the features.

18. The apparatus according to claim 17, wherein the mirror layer is deposited on or substantially opposite a plurality of gratings.

19. The apparatus according to claim 17, wherein the surface is disposed substantially away from the light engine.

20. The apparatus according to claim 17, wherein the mirror layer comprises at least one silver (Ag) material.

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