# US 12,601,861 B2 · Index matching based on gas to liquid phase change > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,861 B2 - Document ID: US12601861B2 - Status: Granted - Kind: B2 - Application number: 18/146,482 - Filed: 2022-12-27 - Published: 2024-06-27 - Granted: 2026-04-14 - Earliest claimed: 2022-12-27 - Assignees: Pixieray Oy - Applicants: Pixieray Oy - Inventors: Klaus Melakari - Web page: https://patentgrep.com/patent/US12601861B2 ## CPC - G02B 3/14: of variable focal length - A61B 3/0025: {characterised by electronic signal processing, e.g. eye models} - A61B 3/113: for determining or recording eye movement - G02B 3/08: with discontinuous faces, e.g. Fresnel lens {(diffractive Fresnel lenses G02B5/1876)} - G02B 26/004: {based on a displacement or a deformation of a fluid} - G02C 7/083: {Electrooptic lenses} - G02C 11/10: {Electronic devices other than hearing aids} - G02B 27/0093: {with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking} - G02B 27/0172: {characterised by optical features} - G02C 2202/16: Laminated or compound lenses - G02C 2202/20: Diffractive and Fresnel lenses or lens portions - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G02C: SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES (trial frames for testing the eyes A61B3/04; goggles or eyeshields not having the same features as spectacles A61F9/00) ## Abstract Disclosed is an optical element with a first substrate and a second substrate. A cavity is formed between first substrate and second substrate; a material, wherein liquid state of material has refractive index that matches refractive index of at least one of: first substrate, second substrate; a liquid reservoir that is to be employed to hold liquid state; a gas reservoir that is to be employed to hold a gaseous state of the material; means for converting gaseous state into liquid state; fluid channel(s) connecting cavity to liquid reservoir and to gas reservoir; and means for controlling supply of liquid state to cavity through fluid channel(s) and for controlling replacement of liquid state with the gaseous state in cavity, wherein given optical power is produced by optical element when cavity is filled with gaseous state. ## Claims ### Claim 1 An optical element comprising: a first substrate and a second substrate that are optically transparent, wherein a cavity is formed between the first substrate and the second substrate; a material that is optically transparent, wherein a liquid state of the material has a refractive index that matches a refractive index of at least one of: the first substrate, the second substrate; a liquid reservoir that is to be employed to hold the liquid state of the material; a gas reservoir that is to be employed to hold a gaseous state of the material; means for converting the gaseous state of the material into the liquid state of the material, said means for converting being connected to the gas reservoir and to the liquid reservoir; at least one fluid channel connecting the cavity to the liquid reservoir and to the gas reservoir; and means for controlling a supply of the liquid state of the material to the cavity through the at least one fluid channel and for controlling a replacement of the liquid state of the material with the gaseous state of the material in the cavity, wherein a given optical power is produced by the optical element when the cavity is filled with the gaseous state of the material. ### Claim 2 (depends on 1) The optical element of claim 1, wherein the given optical power to be produced depends on a curvature of a surface of the at least one of: the first substrate, the second substrate, whose refractive index matches with the refractive index of the liquid state of the material. ### Claim 3 (depends on 1) The optical element of claim 1, wherein the at least one of: the first substrate, the second substrate, whose refractive index matches with the refractive index of the liquid state of the material, is implemented as a Fresnel lens having concentric grooves, wherein the concentric grooves face the material. ### Claim 4 (depends on 1) The optical element of claim 1, wherein said means for converting is implemented as a condenser and/or a compressor. ### Claim 5 (depends on 1) The optical element of claim 1, wherein said means for controlling comprises: a first valve arranged on the at least one fluid channel between the liquid reservoir and the cavity; and a second valve arranged on the at least one fluid channel between the gas reservoir and the cavity. ### Claim 6 (depends on 5) The optical element of claim 5, wherein said means for controlling further comprises a third valve arranged between the means for converting and the liquid reservoir, wherein the third valve is to be employed to control a condensation and/or a compression of the gaseous state of the material into the liquid state of the material. ### Claim 7 (depends on 5) The optical element of claim 5, wherein said means for controlling comprises a plurality of capillaries that are to be employed to control the supply of the liquid state of the material to the cavity. ### Claim 8 (depends on 5) The optical element of claim 5, wherein the liquid state of the material is supplied from the liquid reservoir to the cavity by: opening the first valve arranged between the liquid reservoir and the cavity, while closing the second valve arranged between the gas reservoir and the cavity; and increasing a pressure at the liquid reservoir. ### Claim 9 (depends on 5) The optical element of claim 5, wherein the liquid state of the material is replaced with the gaseous state of the material in the cavity by: closing the first valve arranged between the liquid reservoir and the cavity, while opening the second valve arranged between the gas reservoir and the cavity; and reducing a pressure at the gas reservoir. ### Claim 10 (depends on 1) The optical element of claim 1, further comprising: at least one other substrate, wherein at least one other cavity is formed between the second substrate and the at least one other substrate, and wherein the refractive index of the liquid state of the material matches a refractive index of at least one of: the second substrate, the at least one other substrate; and at least one other fluid channel connecting the at least one other cavity to the liquid reservoir and to the gas reservoir, wherein said means for controlling is to be employed to control a supply of the liquid state of the material to the at least one other cavity through the at least one other fluid channel and to control a replacement of the liquid state of the material with the gaseous state of the material in the at least one other cavity, further wherein the given optical power is produced by the optical element when at least one of: the cavity, the at least one other cavity is filled with the gaseous state of the material. ### Claim 11 (depends on 1) An optical apparatus comprising at least one optical element of claim 1. ### Claim 12 (depends on 11) The optical apparatus of claim 11, further comprising: a frame employed to hold the at least one optical element; and at least one input means, mounted on a temple of the frame, that is to be used by a user to switch on or switch off the at least one optical element. ### Claim 13 (depends on 11) The optical apparatus of claim 11, further comprising a processor and a wireless communication interface that is to be employed to communicably couple the processor of the optical apparatus to a computing device, wherein the computing device is to be used by a user for at least one of: switching on or switching off the at least one optical element, and inputting the given optical power to be produced. ### Claim 14 (depends on 11) The optical apparatus of claim 11, further comprising eye-tracking means and a processor configured to: process eye-tracking data, collected by the eye-tracking means, to determine gaze directions of a user's eyes; determine a given optical depth at which the user is gazing, based on at least one of: the gaze directions of the user's eyes, depth information of a real-world scene currently being seen by the user; determine an optical power prescribed for a given eye of the user corresponding to the given optical depth at which the user is gazing, the optical element being worn in front of the given eye of the user; and determine the given optical power to be produced, based on the optical power prescribed for the given eye of the user.