# US 12,216,257 B2 · Plastic light-folding element, imaging lens assembly module and electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,257 B2 - Document ID: US12216257B2 - Status: Granted - Kind: B2 - Application number: 17/575,713 - Filed: 2022-01-14 - Published: 2022-08-04 - Granted: 2025-02-04 - Earliest claimed: 2021-02-03 - Assignees: Largan Precision Co., Ltd. - Applicants: Largan Precision Co., Ltd. - Inventors: Pei-Chi Chang; Wei-Chun Lo; Po-Lun Hsu; Lin-An Chang; Ming-Ta Chou - Web page: https://patentgrep.com/patent/US12216257B2 ## CPC - G02B 13/0065: {having a beam-folding prism or mirror} - G02B 5/04: Prisms - G02B 13/007: {the beam folding prism having at least one curved surface} - B29C 2045/0027: {Gate or gate mark locations} - B29D 11/0074: {Production of other optical elements not provided for in B29D11/00009- B29D11/0073} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) ## Abstract A plastic light-folding element includes an incident surface, an exit surface, at least one reflective surface, at least one connecting surface and at least one gate vestige structure. The incident surface is configured to lead an imaging light enter the plastic light-folding element. The exit surface is configured to lead the imaging light exit the plastic light-folding element. The reflective surface is configured to fold the imaging light. The connecting surface is connected to the incident surface, the exit surface and the reflective surface. The gate vestige structure is disposed on the connecting surface. At least one of the incident surface, the exit surface and the reflective surface includes an optical portion and an arc step structure, the arc step structure is disposed on a periphery of the optical portion, and an arc is formed by the arc step structure centered on the optical portion. ## Claims ### Claim 1 A plastic light-folding element, comprising: an incident surface configured to let an imaging light enter the plastic light-folding element; an exit surface configured to let the imaging light exit the plastic light-folding element; at least one reflective surface configured to fold the imaging light; at least one connecting surface connected to the incident surface, the exit surface and the at least one reflective surface; and at least one gate vestige structure disposed on the at least one connecting surface; wherein each of the incident surface, the exit surface and the at least one reflective surface comprises an optical portion and an arc step structure, each of the arc step structures is disposed on a periphery of each of the optical portions, and an arc is formed by each of the arc step structures centered on each of the optical portions; wherein an area of the at least one gate vestige structure on the at least one connecting surface is Ag, a total area of the at least one connecting surface is At, a step height of each of the arc step structures is h, and the following conditions are satisfied: 33%≤Ag/At≤90%; and 0.003 mm≤h≤0.17 mm. ### Claim 2 (depends on 1) The plastic light-folding element of claim 1, wherein a number of the at least one connecting surface is two, both of the two connecting surfaces are connected to the incident surface, the exit surface and the at least one reflective surface, and the two connecting surfaces are correspondingly disposed. ### Claim 3 (depends on 2) The plastic light-folding element of claim 2, wherein a number of the at least one gate vestige structure is two, and the two gate vestige structures are disposed on the two connecting surfaces, respectively. ### Claim 4 (depends on 2) The plastic light-folding element of claim 2, wherein the two connecting surfaces are essentially parallel to each other. ### Claim 5 (depends on 1) The plastic light-folding element of claim 1, wherein the at least one connecting surface is essentially orthogonal to the incident surface, the exit surface and the at least one reflective surface, respectively. ### Claim 6 (depends on 1) The plastic light-folding element of claim 1, wherein the optical portion comprises a smooth surface. ### Claim 7 (depends on 1) The plastic light-folding element of claim 1, wherein the optical portion comprises an optical aspheric surface located on a center of the optical portion. ### Claim 8 (depends on 1) The plastic light-folding element of claim 1, wherein the area of the at least one gate vestige structure on the at least one connecting surface is Ag, the total area of the at least one connecting surface is At, and the following condition is satisfied: 35%≤Ag/At≤80%. ### Claim 9 (depends on 1) The plastic light-folding element of claim 1, wherein an abbe number of the plastic light-folding element is V, and the following condition is satisfied: 40≤V≤72. ### Claim 10 (depends on 1) The plastic light-folding element of claim 1, wherein a number of the at least one reflective surface is two, and both of the two reflective surfaces are configured to fold the imaging light. ### Claim 11 (depends on 10) The plastic light-folding element of claim 10, wherein the two reflective surfaces are essentially orthogonal to each other. ### Claim 12 (depends on 10) The plastic light-folding element of claim 10, wherein each of the incident surface, the exit surface and the two reflective surfaces comprises the optical portion and the arc step structure, each of the arc step structures is disposed on the periphery of each of the optical portions, and the arc is formed by each of the arc step structures centered on each of the optical portions. ### Claim 13 (depends on 1) The plastic light-folding element of claim 1, wherein the at least one gate vestige structure comprises an arc rim extending from a center of the at least one gate vestige structure towards an outer side of the at least one gate vestige structure. ### Claim 14 (depends on 1) The plastic light-folding element of claim 1, wherein the step height of each of the arc step structures is h, and the following condition is satisfied: 0.005 mm≤h≤0.07 mm. ### Claim 15 (depends on 1) An imaging lens assembly module, comprising: the plastic light-folding element of claim 1; and an imaging lens element set, wherein the plastic light-folding element is disposed on one of an object side and an image side of the imaging lens element set. ### Claim 16 (depends on 15) An electronic device, comprising: the imaging lens assembly module of claim 15; and an image sensor disposed on an image surface of the imaging lens assembly module.