# US 11,906,751 B2 · Lens for eye-tracking applications and head-worn device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,751 B2 - Document ID: US11906751B2 - Status: Granted - Kind: B2 - Application number: 17/673,167 - Filed: 2022-02-16 - Published: 2022-06-02 - Granted: 2024-02-20 - Earliest claimed: 2019-01-31 - Assignees: Tobii AB - Applicants: Tobii AB - Inventors: Axel Tollin; Daniel Ljunggren - Web page: https://patentgrep.com/patent/US11906751B2 ## CPC - G02B 27/0093: {with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking} - G02B 27/0179: {Display position adjusting means not related to the information to be displayed} - G02B 1/14: Protective coatings, e.g. hard coatings - G02B 5/208: {for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation} - G02B 5/223: {containing organic substances, e.g. dyes, inks or pigments} - G02B 19/009: {for use with infrared radiation} - G02B 27/0172: {characterised by optical features} - G02C 11/04: Illuminating means - G02C 11/10: {Electronic devices other than hearing aids} - G02B 2027/0138: {comprising image capture systems, e.g. camera} - G02B 2027/0178: {Eyeglass type (eyeglass details G02C)} - G02B 2027/0187: {slaved to motion of at least a part of the body of the user, e.g. head, eye} - G02C 2202/16: Laminated or compound lenses - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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 The present invention relates to a lens for eye-tracking applications. The lens comprises a first protective layer, arranged to face towards the eye to be tracked when the lens is used for eye-tracking. It also comprises at least one light source, at least partly arranged in the first protective layer, arranged to emit a first light from the first protective layer in a direction towards the eye. Moreover, it comprises at least one image capturing device, at least partly arranged in the first protective layer, arranged to receive the first light within the first protective layer. The lens further comprises an absorptive layer, arranged on the far side of the first protective layer seen from the eye to be tracked when the lens is used for eye-tracking, adapted to be absorptive for wavelengths of the majority of the first light. ## Claims ### Claim 1 A lens for eye-tracking applications, the lens comprising: a first protective layer with a first surface, arranged to face towards the eye to be tracked when the lens is used for eye-tracking, at least one light source, at least partly arranged in contact with the first protective layer, arranged to emit a first light from the first protective layer in a direction towards the eye, at least one image capturing device, at least partly arranged in contact with the first protective layer, arranged to receive the emitted first light within the first protective layer, a refractive element that is arranged in the light path of the first light, wherein the lens further comprises an absorptive layer, arranged on the far side of the first protective layer seen from the eye to be tracked when the lens is used for eye-tracking, adapted to be absorptive for the majority of the first light. ### Claim 2 (depends on 1) The lens according to claim 1, wherein the light source is a light emitting diode, LED, or a laser. ### Claim 3 (depends on 1) The lens according to claim 1, wherein the absorptive layer is configured to function also as a supporting layer and to support at least one of the at least one light source and the at least one image capturing device. ### Claim 4 (depends on 1) The lens according to claim 1, wherein the lens further comprises a supporting layer configured to support at least one of the at least one light source and the at least one image capturing device, wherein the supporting layer is arranged on either side of the absorptive layer. ### Claim 5 (depends on 1) The lens according to claim 1, wherein a second protective layer is provided on the far side of the absorptive layer, seen from the eye. ### Claim 6 (depends on 1) The lens according to claim 1, wherein a second protective layer is provided on the far side of the supporting layer, seen from the eye, and wherein the second protective layer is the absorptive layer. ### Claim 7 (depends on 1) The lens according to claim 1, wherein the light source is adapted to emit the first light essentially at wavelengths in the wavelength range 650-3000 nm, preferably in the wavelength range 750-1400 nm, more preferably in the wavelength range 800-1000 nm, and wherein the supporting layer and/or the absorptive layer are adapted to be absorptive for said wavelengths. ### Claim 8 (depends on 1) The lens according to claim 1, wherein the supporting layer, the second protective layer and/or the absorptive layer are essentially transparent for visible wavelengths. ### Claim 9 (depends on 1) The lens according to claim 1, wherein the surface of the refractive element, arranged to face towards the eye, has a convex shape, such that the emission cone of the first light is emitted onto the convex surface with an angle of incidence, which relative to the convex surface is smaller than the critical angle at which total internal reflection would occur. ### Claim 10 (depends on 9) The lens according to claim 9, wherein the refractive element is an integral part of the first protective layer and has a refractive index, which is substantially equal to the refractive index of the first protective layer. ### Claim 11 (depends on 1) The lens according to claim 1, wherein the refractive element has a refractive index substantially equal to the refractive index of the first protective layer and is arranged on the first surface of the first protective layer. ### Claim 12 (depends on 1) The lens according to claim 1, wherein the refractive element has a refractive index that is higher than the refractive index of the first protective layer and wherein the refractive element is positioned such that the first protective layer is surrounding the refractive element. ### Claim 13 (depends on 12) The lens according to claim 12, wherein the refractive index of the refractive element is 15-100% higher than the refractive index of the first protective layer, more preferably 30-50% higher than the refractive index of the first protective layer. ### Claim 14 A head-worn device, with eye-tracking capability comprising: at least one lens for eye-tracking applications wherein the lens has a first protective layer with a first surface, arranged to face towards the eye to be tracked when the lens is used for eye-tracking; at least one light source, at least partly arranged in contact with the first protective layer, arranged to emit a first light from the first protective layer in a direction towards the eye; at least one image capturing device, at least partly arranged in contact with the first protective layer, arranged to receive the emitted first light within the first protective layer; and a refractive element that is arranged in the light path of the first light; wherein the lens further comprises an absorptive layer, arranged on the far side of the first protective layer seen from the eye to be tracked when the lens is used for eye-tracking, adapted to be absorptive for the majority of the first light. ### Claim 15 (depends on 14) The head-worn device according to claim 14, wherein the head-worn device is: an augmented reality headset, where a transparent display is either integrated into the lens, attached to the lens or arranged in the vicinity of the lens; or a virtual reality headset, comprising a display wherein the lens is either integrated into the display, attached in front of the display or arranged in front of the display. ### Claim 16 An eye tracking system comprising: at least one lens for eye-tracking applications wherein the lens has a first protective layer with a first surface, arranged to face towards the eye to be tracked when the lens is used for eye-tracking; at least one light source, at least partly arranged in contact with the first protective layer, arranged to emit a first light from the first protective layer in a direction towards the eye; at least one image capturing device, at least partly arranged in contact with the first protective layer, arranged to receive the emitted first light within the first protective layer; and a refractive element that is arranged in the light path of the first light, wherein the lens further comprises an absorptive layer, arranged on the far side of the first protective layer seen from the eye to be tracked when the lens is used for eye-tracking, adapted to be absorptive for the majority of the first light. ### Claim 17 (depends on 16) The eye tracking system according to claim 16, wherein the surface of the refractive element, arranged to face towards the eye, has a convex shape, such that the emission cone of the first light is emitted onto the convex surface with an angle of incidence, which relative to the convex surface is smaller than the critical angle at which total internal reflection would occur. ### Claim 18 (depends on 16) The eye tracking system according to claim 16, wherein the refractive element is an integral part of the first protective layer and has a refractive index, which is substantially equal to the refractive index of the first protective layer. ### Claim 19 (depends on 16) The eye tracking system according to claim 16, wherein the lens further comprises a supporting layer configured to support at least one of the at least one light source and the at least one image capturing device, wherein the supporting layer is arranged on either side of the absorptive layer. ### Claim 20 (depends on 16) The eye tracking system according to claim 16, wherein a second protective layer is provided on the far side of the absorptive layer, seen from the eye.