Patents by Inventor Nihar Ranjan Mohanty

Nihar Ranjan Mohanty has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10976483
    Abstract: Disclosed herein are techniques for fabricating straight or slanted variable-etch-depth gratings. A photoresist material for fabricating a variable-etch-depth grating in a substrate is sensitive to light with a wavelength shorter than 300 nm and has an etch rate comparable to the etch rate of the substrate. A depth of an exposed portion of a photoresist material layer including the photoresist material correlates with the exposure dose. After exposure using a gray-scale mask and development, the photoresist material layer has a non-uniform thickness. The photoresist material layer with the non-uniform thickness and the underlying substrate are etched using a straight etching or slanted etching process to form the straight or slanted variable-etch-depth grating in the substrate. The variable-etch-depth grating is characterized by a non-uniform depth profile corresponding to the non-uniform thickness of the photoresist material layer before etching.
    Type: Grant
    Filed: February 24, 2020
    Date of Patent: April 13, 2021
    Assignee: FACEBOOK TECHNOLOGIES, LLC
    Inventors: Ankit Vora, Nihar Ranjan Mohanty, Austin Lane, Matthew E. Colburn, Elliott Franke
  • Publication number: 20210055460
    Abstract: A pupil replication waveguide for a projector display includes a slab of transparent material for propagating display light in the slab via total internal reflection. A diffraction grating is supported by the slab. The diffraction grating includes a plurality of tapered slanted fringes in a substrate for out-coupling the display light from the slab by diffraction into a blazed diffraction order. A greater portion of the display light is out-coupled into the blazed diffraction order, and a smaller portion of the display light is out-coupled into a non-blazed diffraction order. The tapered fringes result in the duty cycle of the diffraction grating varying along the thickness direction of the diffraction grating, to facilitate suppressing the portion of the display light out-coupled into the non-blazed diffraction order.
    Type: Application
    Filed: August 23, 2019
    Publication date: February 25, 2021
    Inventors: Hee Yoon Lee, Ningfeng Huang, Pasi Saarikko, Yu Shi, Giuseppe Calafiore, Nihar Ranjan Mohanty
  • Patent number: 10895671
    Abstract: Ion implantation is used to fabricate an optical device having a varying refractive index. The optical device can include a substrate with a material disposed on the substrate. A refractive index of the material is changed by ion implantation. The material can also be etched or imprinted. The optical device can be used in a virtual-reality system or augmented-reality system to provide angular selectivity from a display to a user's eye.
    Type: Grant
    Filed: January 23, 2018
    Date of Patent: January 19, 2021
    Assignee: FACEBOOK TECHNOLOGIES, LLC
    Inventors: Giuseppe Calafiore, Austin Lane, Matthew E. Colburn, Nihar Ranjan Mohanty
  • Patent number: 10845526
    Abstract: A pupil replication waveguide for a projector display includes a slab of transparent material for propagating display light in the slab via total internal reflection. A diffraction grating is supported by the slab. The diffraction grating includes a plurality of slanted fringes in a substrate for out-coupling the display light from the slab by diffraction into a blazed diffraction order. A greater portion of the display light is out-coupled into the blazed diffraction order, and a smaller portion of the display light is out-coupled into a non-blazed diffraction order. A refractive index contrast profile of the diffraction grating along a thickness direction of the diffraction grating is symmetrical, and a refractive index contrast is larger at a middle than at both sides of the refractive index contrast profile, whereby the portion of the display light out-coupled into the non-blazed diffraction order is decreased.
    Type: Grant
    Filed: August 23, 2019
    Date of Patent: November 24, 2020
    Assignee: FACEBOOK TECHNOLOGIES, LLC
    Inventors: Hee Yoon Lee, Ningfeng Huang, Pasi Saarikko, Yu Shi, Giuseppe Calafiore, Nihar Ranjan Mohanty
  • Patent number: 10838121
    Abstract: A three-dimensional diffraction grating is generated by selective deposition and/or selective etching. The three-dimensional diffraction grating includes a substrate and a plurality of structures located at different positions on the substrate. The structures have different materials. Edges of at least some of the structures are aligned. The three-dimensional diffraction grating includes different materials and aligned edges in all three dimensions. With the different materials and aligned edges, the three-dimensional diffraction gratings is configured to eliminate display artifacts, such as ghost, rainbow, etc.
    Type: Grant
    Filed: March 15, 2019
    Date of Patent: November 17, 2020
    Assignee: Facebook Technologies, LLC
    Inventors: Nihar Ranjan Mohanty, Giuseppe Calafiore, Matthew E. Colburn, Austin Lane, Matthieu Charles Raoul Leibovici
  • Publication number: 20200333531
    Abstract: A manufacturing system performs a deposition of an etch-compatible film over a substrate. The etch-compatible film includes a first surface and a second surface opposite to the first surface. The manufacturing system performs a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of depths relative to the substrate. The manufacturing system performs a deposition of a second material over the profile created in the etch-compatible film. The manufacturing system performs a planarization of the second material to obtain a plurality of etch heights of the second material in accordance with the plurality of depths in the profile created in the etch-compatible film. The manufacturing system performs a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of etch heights and one or more duty cycles in the second material.
    Type: Application
    Filed: July 1, 2020
    Publication date: October 22, 2020
    Inventors: Matthew E. Colburn, Giuseppe Calafiore, Matthieu Charles Raoul Leibovici, Nihar Ranjan Mohanty
  • Publication number: 20200271850
    Abstract: Disclosed herein are techniques for fabricating straight or slanted variable-etch-depth gratings. A photoresist material for fabricating a variable-etch-depth grating in a substrate is sensitive to light with a wavelength shorter than 300 nm and has an etch rate comparable to the etch rate of the substrate. A depth of an exposed portion of a photoresist material layer including the photoresist material correlates with the exposure dose. After exposure using a gray-scale mask and development, the photoresist material layer has a non-uniform thickness. The photoresist material layer with the non-uniform thickness and the underlying substrate are etched using a straight etching or slanted etching process to form the straight or slanted variable-etch-depth grating in the substrate. The variable-etch-depth grating is characterized by a non-uniform depth profile corresponding to the non-uniform thickness of the photoresist material layer before etching.
    Type: Application
    Filed: February 24, 2020
    Publication date: August 27, 2020
    Inventors: Ankit VORA, Nihar Ranjan MOHANTY, Austin LANE, Matthew E. COLBURN, Elliott FRANKE
  • Publication number: 20200264362
    Abstract: A chemically assisted reactive ion beam etching (CAME) system for fabricating a slanted surface-relief structure in a material layer includes an reactive ion source generator configured to generate a plasma using a first reactive gas; one or more aligned collimator grids configured to extract and accelerate at least some of the reactive ions in the plasma to form a collimated reactive ion beam towards the material layer; and a gas ring configured to inject a second reactive gas onto the material layer. The plasma includes reactive ions of the first reactive gas that react with the material layer to generate volatile materials. The second reactive gas also reacts with the material layer. The collimated reactive ion beam and the second reactive gas etch the material layer both physically and chemically to form the slanted surface-relief structure in the material layer.
    Type: Application
    Filed: May 6, 2020
    Publication date: August 20, 2020
    Inventor: Nihar Ranjan Mohanty
  • Publication number: 20200264353
    Abstract: A surface-relief grating includes a base surface-relief grating comprising a plurality of ridges that include a first material, and a second material on only a top surface or a single sidewall of each ridge of the plurality of ridges, where the second material is different from the first material. A method of fabricating the surface-relief grating includes etching or molding a base surface-relief grating that includes a plurality of ridges, depositing a material layer on the plurality of ridges, and selectively etching the material layer to increase a height or a slant angle of an edge of a ridge in the plurality of ridges to make the surface-relief grating that includes the base surface-relief grating.
    Type: Application
    Filed: May 7, 2020
    Publication date: August 20, 2020
    Inventors: Nihar Ranjan Mohanty, Matthieu Charles Raoul Leibovici
  • Publication number: 20200249386
    Abstract: Techniques for fabricating a slanted structure are disclosed. In one embodiment, a method of fabricating a slanted surface-relief structure in a material layer includes forming a thin hard mask on top of an intermediate mask layer, etching the intermediate mask layer at a slant angle using the thin hard mask to form a slanted intermediate mask, and etching the material layer at the slant angle using the slanted intermediate mask to form the slanted surface-relief structure in the material layer. The intermediate mask layer is characterized by an etch rate greater than an etch rate of the material layer.
    Type: Application
    Filed: January 31, 2019
    Publication date: August 6, 2020
    Inventors: Nihar Ranjan Mohanty, Matthew E. Colburn
  • Patent number: 10732351
    Abstract: A manufacturing system performs a deposition of an etch-compatible film over a substrate. The etch-compatible film includes a first surface and a second surface opposite to the first surface. The manufacturing system performs a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of depths relative to the substrate. The manufacturing system performs a deposition of a second material over the profile created in the etch-compatible film. The manufacturing system performs a planarization of the second material to obtain a plurality of etch heights of the second material in accordance with the plurality of depths in the profile created in the etch-compatible film. The manufacturing system performs a lithographic patterning of a photoresist deposited over the planarized second material to obtain the plurality of etch heights and one or more duty cycles in the second material.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: August 4, 2020
    Assignee: Facebook Technologies, LLC
    Inventors: Matthew E. Colburn, Giuseppe Calafiore, Matthieu Charles Raoul Leibovici, Nihar Ranjan Mohanty
  • Patent number: 10712481
    Abstract: A method for fabricating a diffraction grating includes generating an ionized gas, passing the ionized gas through a gating structure to selectively directed gas toward a substrate, injecting an etchant gas into the directed gas, and exposing a surface of the substrate to the directed gas and the injected etchant gas to form grating structures on the surface of the substrate.
    Type: Grant
    Filed: August 3, 2018
    Date of Patent: July 14, 2020
    Assignee: Facebook Technologies, LLC
    Inventors: Nihar Ranjan Mohanty, Giuseppe Calafiore, Matthew E. Colburn, Austin Lane, Matthieu Charles Raoul Leibovici
  • Publication number: 20200213579
    Abstract: Techniques for producing an overcoat layer on slanted surface-relief structures and devices obtained using the techniques are disclosed. In some embodiments, a method of planarizing an overcoat layer over a surface-relief structure includes removing a portion of the overcoat layer using an ion beam at a glancing angle. The overcoat layer includes planar surface portions and non-planar surface portions. Each of the non-planar surface portions includes a first sloped side and a second sloped side facing the first sloped side. The glancing angle is selected such that the first sloped side of each non-planar surface portion is shadowed from the ion beam by an adjacent planar surface portion such that the ion beam does not reach at least the first sloped side of each non-planar surface portion but reaches the second sloped side of each non-planar surface portion.
    Type: Application
    Filed: October 22, 2019
    Publication date: July 2, 2020
    Inventor: Nihar Ranjan MOHANTY
  • Publication number: 20200209483
    Abstract: Techniques for overcoating slanted structures and devices obtained using the techniques are disclosed. In some embodiments, a method of forming an overcoat layer on a surface-relief structure on a substrate includes receiving the substrate with the surface-relief structure. The surface-relief structure includes a plurality of ridges slanted with respect to the substrate, and a plurality of grooves each between two adjacent ridges. The method further includes depositing, in each cycle of a plurality of cycles, a uniform layer of an overcoat material on surfaces of the plurality of ridges and bottoms of the plurality of grooves. The deposited layers of the overcoat material and the plurality of ridges collectively form a light-coupling structure on the substrate. A surface of the overcoat layer is planar.
    Type: Application
    Filed: October 22, 2019
    Publication date: July 2, 2020
    Inventor: Nihar Ranjan MOHANTY
  • Patent number: 10684407
    Abstract: Techniques for fabricating a slanted structure are disclosed. In one embodiment, a method of fabricating a slanted structure in a material layer includes injecting a first reactive gas into an reactive ion source generator, generating a plasma that includes reactive ions in the reactive ion source generator, extracting at least some of the reactive ions from the plasma to form a collimated reactive ion beam towards the material layer, and injecting a second reactive gas onto the material layer. The collimated reactive ion beam and the second reactive gas etch the material layer both physically and chemically to form the slanted surface-relief structure.
    Type: Grant
    Filed: June 6, 2018
    Date of Patent: June 16, 2020
    Assignee: Facebook Technologies, LLC
    Inventor: Nihar Ranjan Mohanty
  • Patent number: 10649119
    Abstract: Techniques for fabricating slanted surface-relief structures are disclosed. In some embodiments, a method for of fabricating a target slanted surface-relief structure, such as a nanoimprint lithography (NIL) mold or a slanted surface-relief grating, includes manufacturing a preliminary surface-relief structure that includes a plurality of ridges and modifying a parameter of the preliminary surface-relief structure to make the target slanted surface-relief structure. The parameter includes a width of each of the plurality of ridges, a height of each of the plurality of ridges, a surface energy of the preliminary surface-relief structure, or a slant angle of an edge of the plurality of ridges. Modifying the parameter includes depositing a material layer on the preliminary surface-relief structure and etching or surface-treating the material layer.
    Type: Grant
    Filed: July 16, 2018
    Date of Patent: May 12, 2020
    Assignee: Facebook Technologies, LLC
    Inventors: Nihar Ranjan Mohanty, Matthieu Charles Raoul Leibovici
  • Patent number: 10649141
    Abstract: A manufacturing system performs a deposition of an etch-compatible film over a substrate. The etch-compatible film includes a first surface and a second surface opposite to the first surface. The manufacturing system performs a partial removal of the etch-compatible film to create a surface profile on the first surface with a plurality of etch heights relative to the substrate. The manufacturing system performs a lithographic patterning of a photoresist deposited over the created profile in the etch-compatible film to obtain the plurality of etch heights and one or more duty cycles corresponding to the etch-compatible film deposited over the substrate.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: May 12, 2020
    Assignee: Facebook Technologies, LLC
    Inventors: Matthew E. Colburn, Giuseppe Calafiore, Matthieu Charles Raoul Leibovici, Nihar Ranjan Mohanty
  • Publication number: 20200033530
    Abstract: Techniques for fabricating a slanted structure are disclosed. In one embodiment, a method for fabricating a slanted structure on a material layer includes forming a mask layer on the material layer, and implanting ions into a plurality of regions of the material layer at a slant angle greater than zero using an ion beam and the mask layer. The slant angle is measured with respect to a surface normal of the material layer. Implanting the ions into the plurality of regions of the material layer changes a refractive index or an etch rate of the plurality of regions of the material layer. In some embodiments, the method further includes wet-etching the material layer using an etchant to remove materials in the plurality of regions of the material layer. In some embodiments, the method includes either simultaneous or post-implantation etching of modified material through a dry etching process using reactive etchants in feed gas.
    Type: Application
    Filed: July 26, 2018
    Publication date: January 30, 2020
    Inventors: Matthew E. Colburn, Nihar Ranjan Mohanty
  • Publication number: 20200018875
    Abstract: Techniques for fabricating slanted surface-relief structures are disclosed. In some embodiments, a method for of fabricating a target slanted surface-relief structure, such as a nanoimprint lithography (NIL) mold or a slanted surface-relief grating, includes manufacturing a preliminary surface-relief structure that includes a plurality of ridges and modifying a parameter of the preliminary surface-relief structure to make the target slanted surface-relief structure. The parameter includes a width of each of the plurality of ridges, a height of each of the plurality of ridges, a surface energy of the preliminary surface-relief structure, or a slant angle of an edge of the plurality of ridges. Modifying the parameter includes depositing a material layer on the preliminary surface-relief structure and etching or surface-treating the material layer.
    Type: Application
    Filed: July 16, 2018
    Publication date: January 16, 2020
    Inventors: Nihar Ranjan Mohanty, Matthieu Charles Raoul Leibovici
  • Patent number: 10502958
    Abstract: Techniques for fabricating a slanted structure are disclosed. In one embodiment, a method of fabricating a slanted structure in a material layer includes injecting a first reactive gas into an reactive ion source generator, generating a plasma that includes reactive ions in the reactive ion source generator, extracting at least some of the reactive ions from the plasma to form a collimated reactive ion beam towards the material layer, and injecting a second reactive gas onto the material layer. The collimated reactive ion beam and the second reactive gas etch the material layer both physically and chemically to form the slanted surface-relief structure. In some embodiments, the first reactive gas includes a low-molecular-weight gas (e.g., H2 or He). In some embodiments, a surface layer of the internal cavity of the reactive ion source generator includes a layer of an oxide material (e.g., aluminum oxide or Y2O3).
    Type: Grant
    Filed: October 30, 2018
    Date of Patent: December 10, 2019
    Assignee: Facebook Technologies, LLC
    Inventor: Nihar Ranjan Mohanty