# US 2025/0164765 A1 · Catadioptric lens system and video see-through device equipped therewith > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0164765 A1 - Document ID: US20250164765A1 - Status: Published application - Kind: A1 - Application number: 19/033,197 - Filed: 2025-01-21 - Published: 2025-05-22 - Earliest claimed: 2022-07-21 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Youngmo JEONG; Jongchul Choi - Web page: https://patentgrep.com/patent/US20250164765A1 ## CPC - G02B 17/08: Catadioptric systems {(used in non-imaging applications G02B19/00)} - G02B 27/0172: {characterised by optical features} - G02B 27/283: {used for beam splitting or combining} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Provided is a catadioptric lens system implemented in a video see-through apparatus, the catadioptric lens system including a first lens, a second lens, a third lens, and a fourth lens sequentially disposed in a direction of an optical axis from a side of a user's eye toward a side of an image surface, wherein a second surface of the first lens facing the image surface is configured to reflect at least a portion of light from the second lens and a fourth surface of the second lens facing the image surface is configured to re-reflect at least a portion of light reflected from the first lens, wherein the first lens has a positive refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, and wherein the first lens is configured to move. ## Claims ### Claim 1 A catadioptric lens system implemented in a video see-through apparatus, the catadioptric lens system comprising: a first lens; a second lens; a third lens; and a fourth lens, wherein the first lens, the second lens, the third lens, and the fourth lens are sequentially disposed in a direction of an optical axis from a side of a user's eye toward a side of an image surface, wherein a second surface of the first lens facing the image surface is configured to reflect at least a portion of light from the second lens and a fourth surface of the second lens facing the image surface is configured to re-reflect at least a portion of light reflected from the first lens, wherein the first lens has a positive refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, wherein the first lens is configured to move in the direction of the optical axis within a distance range of 0.1 mm to 1.1 mm from the second lens, and wherein a change of refractive power within a movement range of the first lens is within a range of −7D to +1D. ### Claim 2 (depends on 1) The catadioptric lens system of claim 1, wherein the first lens is further configured to move in the direction of the optical axis within a distance range of 0.15 mm to 1.03 mm from the second lens. ### Claim 3 (depends on 1) The catadioptric lens system of claim 1, wherein a modulation transfer function (MTF) of 0.5 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.6 at fs/4, and wherein the MTF of 0.5 field within the movement range of the first lens is greater than or equal to 70% 0.6. ### Claim 4 (depends on 1) The catadioptric lens system of claim 1, wherein a modulation transfer function (MTF) of 0.7 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.5 at fs/4, and wherein the MTF of 0.7 field within a range in which a magnification is adjusted is greater than or equal to 70% of 0.5. ### Claim 5 (depends on 1) The catadioptric lens system of claim 1, wherein a modulation transfer function (MTF) of 0.8 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.4 at fs/4, and wherein the MTF of 0.8 field within a range in which a magnification is adjusted is greater than or equal to 70% of 0.4. ### Claim 6 (depends on 1) The catadioptric lens system of claim 1, wherein an eye relief of the catadioptric lens system is within a range of 11 mm to 14 mm. ### Claim 7 (depends on 1) The catadioptric lens system of claim 1, wherein a field of view of the catadioptric lens system is within a range of 85° to 95°. ### Claim 8 (depends on 1) The catadioptric lens system of claim 1, further comprising: a reflection polarizer between the first lens and the second lens; a quarter-wavelength plate between the reflection polarizer and the second lens; and a half mirror between the second lens and the third lens. ### Claim 9 (depends on 8) The catadioptric lens system of claim 8, wherein the reflection polarizer and the quarter-wavelength plate are in a film form and on the second surface of the first lens. ### Claim 10 (depends on 8) The catadioptric lens system of claim 8, further comprising a second quarter-wavelength plate between the fourth lens and the image surface. ### Claim 11 (depends on 8) The catadioptric lens system of claim 8, further comprising a linear polarizer and a second quarter-wavelength plate on an image-surface-side of the fourth lens. ### Claim 12 (depends on 1) The catadioptric lens system of claim 1, wherein the first lens, the second lens, the third lens, and the fourth lens comprise a plastic lens. ### Claim 13 (depends on 1) The catadioptric lens system of claim 1, wherein the first lens, the second lens, the third lens, and the fourth lens comprise an aspherical lens. ### Claim 14 (depends on 1) The catadioptric lens system of claim 1, wherein the second surface of the first lens comprises a flat surface. ### Claim 15 A video see-through apparatus comprising: a display panel configured to output light of an image; and a catadioptric lens system comprising: a first lens; a second lens; a third lens; and a fourth lens, wherein the first lens, the second lens, the third lens, and the fourth lens are sequentially disposed in a direction of an optical axis from a side of a user's eye toward a side of an image surface, wherein a second surface of the first lens facing the image surface is configured to reflect at least a portion of light from the second lens and a fourth surface of the second lens facing the image surface is configured to re-reflect at least a portion of light reflected from the first lens, wherein the first lens has a positive refractive power, the second lens has a positive refractive power, the third lens has a negative refractive power, and the fourth lens has a positive refractive power, wherein the first lens is configured to move in the direction of the optical axis within a distance range of 0.1 mm to 1.1 mm from the second lens, and wherein a change of refractive power within a movement range of the first lens is within a range of −7D to +1D. ### Claim 16 (depends on 15) The video see-through apparatus of claim 15, wherein the first lens is further configured to move in the direction of the optical axis within a distance range of 0.15 mm to 1.03 mm from the second lens. ### Claim 17 (depends on 15) The video see-through apparatus of claim 15, wherein a modulation transfer function (MTF) of 0.5 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.6 at fs/4, and wherein the MTF of 0.5 field within the movement range of the first lens is greater than or equal to 70% 0.6. ### Claim 18 (depends on 15) The video see-through apparatus of claim 15, wherein an MTF of 0.7 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.5 at fs/4, and wherein the MTF of 0.7 field within a range in which a magnification is adjusted is greater than or equal to 70% of 0.5. ### Claim 19 (depends on 15) The video see-through apparatus of claim 15, wherein an MTF of 0.8 field at a predetermined wavelength and a predetermined vision is greater than or equal to 0.4 at fs/4, and wherein the MTF of 0.8 field within a range in which a magnification is adjusted is greater than or equal to 70% of 0.4. ### Claim 20 (depends on 15) The video see-through apparatus of claim 15, wherein an eye relief of the catadioptric lens system is within a range of 11 mm to 14 mm.