# US 12,111,471 B2 · Free-form prism-lens group and near-eye display apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,471 B2 - Document ID: US12111471B2 - Status: Granted - Kind: B2 - Application number: 17/658,651 - Filed: 2022-04-10 - Published: 2022-07-28 - Granted: 2024-10-08 - Earliest claimed: 2016-12-08 - Assignees: Beijing NED+AR Display Technology Co., Ltd. - Applicants: Beijing NED+AR Display Technology Co., Ltd. - Inventors: Dewen Cheng; Qiwei Wang - Web page: https://patentgrep.com/patent/US12111471B2 ## CPC - G02B 27/0172: {characterised by optical features} - G02B 5/04: Prisms - G02B 27/01: Head-up displays - G02B 27/0955: {Lenses (lenses per se G02B3/00)} - G02B 27/0972: {Prisms (prisms per se G02B5/04)} - G02B 27/12: operating by refraction only - G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)} - G02B 1/11: Anti-reflection coatings - G02B 17/086: {wherein the system is made of a single block of optical material, e.g. solid catadioptric systems} - G02B 27/142: {Coating structures, e.g. thin films multilayers} - G02B 2027/011: {comprising device for correcting geometrical aberrations, distortion} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A free-form prism-lens group includes: a primary prism, a first auxiliary lens and a second auxiliary lens, the primary prism includes three optical surfaces, the first auxiliary lens is arranged adjacent to the primary prism and is not used for imaging the image light entering the first auxiliary lens; the second auxiliary lens is arranged adjacent to the primary prism and a gap with a predetermined thickness is arranged between the second auxiliary lens and the primary prism, the second auxiliary lens extends in a direction perpendicular to an optical axis to cover an effective aperture of the image light entering the second auxiliary lens from the primary prism. ## Claims ### Claim 1 A free-form prism-lens group, comprising: a primary prism, a first auxiliary lens, and a second auxiliary lens; wherein: the primary prism has a plurality of surfaces including only three optical surfaces; a first optical surface is configured as an incident surface facing a micro-display device for receiving an image light from the micro-display device, and transmitting the image light into the primary prism; a second optical surface is configured as an exit surface; a third optical surface is configured to reflect the image light back into the primary prism once during a process of the image light propagated from the first optical surface to the second optical surface and exiting from the primary prism; the first optical surface, the second optical surface, and the third optical surface are free-form surfaces; the first auxiliary lens is arranged adjacent to the primary prism and is not configured for imaging of the image light; the second auxiliary lens is arranged adjacent to the primary prism and a gap with a predetermined thickness is arranged between the second auxiliary lens and the primary prism, and the adjacent surfaces of the primary prism and the second auxiliary lens have consistent free-form surfaces to satisfy the condition of total internal reflection of the image light when the image light reaches the second optical surface for a first time; the second auxiliary lens extends in a direction perpendicular to an optical axis to cover an effective aperture of the image light entering the second auxiliary lens from the primary prism; and the primary prism has extended edge portions disposed symmetrically about a vertical plane passing through the optical axis and extending from the first optical surface and the third optical surface, respectively, such that the freeform prism-lens group has a size not limited by the micro-display device, the extended edge portions have non-free-form surfaces and are not configured as optical surfaces for imaging of the image light while having smooth transitions with the first optical surface and the third optical surface, respectively. ### Claim 2 (depends on 1) The free-form prism-lens group of claim 1, wherein the free-form prism-lens group has an outer surface facing an environment side and an outer surface facing the exit pupil side, the outer surface facing the environment side and the outer surface facing the exit pupil side are planar, aspheric, or spherical with a curvature radius greater than 100 mm. ### Claim 3 (depends on 2) The free-form prism-lens group of claim 2, wherein the outer surface facing the environment side and the outer surface facing the exit pupil side are spherical surfaces or aspherical surfaces, and the outer surface facing the environment side have a different shape with the outer surface facing the exit pupil side, thereby adding a predetermined diopter compensation to environmental light. ### Claim 4 (depends on 2) The free-form prism-lens group of claim 2, wherein the outer surface facing the environment side has an identical shape as the outer surface facing the exit pupil side, such that environmental light does not change direction after passing through the free-form prism-lens group. ### Claim 5 (depends on 2) The free-form prism-lens group of claim 2, wherein the outer surface facing the environment side and the outer surface facing the exit pupil side are coated with hardening films and anti-reflection films. ### Claim 6 (depends on 1) The free-form prism-lens group of claim 1, wherein the first auxiliary lens is coupled to the primary prism by gluing. ### Claim 7 (depends on 1) The free-form prism-lens group of claim 1, wherein the predetermined thickness of the gap is not more than 1 mm. ### Claim 8 (depends on 1) The free-form prism-lens group of claim 1, wherein the third optical surface of the primary prism is coated with a beamsplitter film having a predetermined beamsplitting ratio. ### Claim 9 (depends on 1) The free-form prism-lens group of claim 1, wherein the first auxiliary lens and the second auxiliary lens do not exceed an outer edge of the primary prism in the direction of the optical axis, so that a maximum thickness of the free-form prism-lens group in the direction of the optical axis is determined by a maximum thickness of the outer edge of the primary prism. ### Claim 10 (depends on 9) The free-form prism-lens group of claim 9, wherein the maximum thickness does not exceed 15 mm. ### Claim 11 (depends on 1) The free-form prism-lens group of claim 1, wherein the free-form prism-lens group is capable of enlarging the image displayed by the micro-display device to achieve a field of view of more than 50°. ### Claim 12 (depends on 1) A near-eye display apparatus, comprising: the free-form prism-lens group of claim 1; and the micro-display device, positioned over the first optical surface of the primary prism; wherein the apparatus is further configured to have a dioptric correction of a user vision with at least one of myopia, hyperopia, or astigmatism. ### Claim 13 (depends on 12) The near-eye display apparatus of claim 12, further comprising a controller and a controllable optical filter, wherein the controllable optical filter is attached to an outer surface facing an environment side of the free-form prism-lens group, wherein the controllable optical filter is coupled to the controller and is driven with the micro-display synchronously. ### Claim 14 (depends on 12) The near-eye display apparatus of claim 12, wherein the free-form prism-lens group has an outer surface facing an environment side and an outer surface facing the exit pupil side, the outer surface facing the environment side and the outer surface facing the exit pupil side are planar, aspheric, or spherical with a curvature radius greater than 100 mm. ### Claim 15 (depends on 14) The near-eye display apparatus of claim 14, wherein the outer surface facing the environment side and the outer surface facing the exit pupil side are spherical surfaces or aspherical surfaces, and the outer surface facing the environment side have a different shape with the outer surface facing the exit pupil side, thereby adding a predetermined diopter compensation to the environmental light. ### Claim 16 (depends on 14) The near-eye display apparatus of claim 14, wherein the outer surface facing the environment side has an identical shape as the outer surface facing the exit pupil side, such that environmental light does not change direction after passing through the free-form prism-lens group. ### Claim 17 (depends on 14) The near-eye display apparatus of claim 14, wherein the outer surface facing the environment side and the outer surface facing the exit pupil side are coated with hardening films and anti-reflection films. ### Claim 18 (depends on 12) The near-eye display apparatus of claim 12, wherein the first auxiliary lens is coupled to the primary prism by gluing. ### Claim 19 (depends on 12) The near-eye display apparatus of claim 12, wherein the predetermined thickness of the gap is not more than 1 mm. ### Claim 20 (depends on 1) The free-form prism-lens group of claim 1, wherein the free-form prism-lens group is further configured to have a dioptric correction for user vision with at least one type of myopia, hyperopia, or astigmatism.