# US 11,306,900 B2 · Plant growth lighting fixture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,900 B2 - Document ID: US11306900B2 - Status: Granted - Kind: B2 - Application number: 17/220,060 - Filed: 2021-04-01 - Published: 2021-07-15 - Granted: 2022-04-19 - Earliest claimed: 2018-12-14 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Satoshi Kuniyasu; Ryosuke Shimizu - Web page: https://patentgrep.com/patent/US11306900B2 ## CPC - F21V 17/002: {with provision for interchangeability, i.e. component parts being especially adapted to be replaced by another part with the same or a different function (F21V17/10 takes precedence)} - A01G 7/045: {with electric lighting} - F21S 4/28: rigid, e.g. LED bars - F21V 9/14: for producing polarised light - G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00) - F21Y 2103/10: comprising a linear array of point-like light-generating elements - F21Y 2115/10: Light-emitting diodes [LED] - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12) - F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED ## Abstract A plant growth lighting fixture includes a lighting fixture main body having a light exit surface, a light source held on the lighting fixture main body, and a reflective-type circularly polarizing plate that selectively reflects circularly polarized light having a particular rotational direction in a particular wavelength range. The reflective-type circularly polarizing plate has a support and a circularly polarized light reflecting layer held on the support. The lighting fixture main body has a holding mechanism for detachably mounting the reflective-type circularly polarizing plate with a main surface of the reflective-type circularly polarizing plate facing the light exit surface. ## Claims ### Claim 1 A plant growth lighting fixture comprising, a lighting fixture main body having a light exit surface; a light source held on the lighting fixture main body; and a reflective-type circularly polarizing plate that selectively reflects circularly polarized light having a particular rotational direction in a particular wavelength range, wherein the reflective-type circularly polarizing plate has a support and a circularly polarized light reflecting layer held on the support, the lighting fixture main body has a holding mechanism for detachably mounting the reflective-type circularly polarizing plate with a main surface of the reflective-type circularly polarizing plate facing the light exit surface, and the holding mechanism has grooves that accommodate two opposite end portions of the reflective-type circularly polarizing plate, and the reflective-type circularly polarizing plate is detachably mounted by inserting the two opposite end portions of the reflective-type circularly polarizing plate into the grooves. ### Claim 2 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the support has an in-plane retardation Re (550) of 50 nm or less. ### Claim 3 (depends on 2) The plant growth lighting fixture according to claim 2, wherein the plant growth lighting fixture includes the light source, the circularly polarized light reflecting layer, and the support, in this order. ### Claim 4 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the circularly polarized light reflecting layer has a cholesteric liquid crystal layer formed by fixing a cholesteric liquid crystalline phase. ### Claim 5 (depends on 1) The plant growth lighting fixture according to claim 1, wherein in a state where the holding mechanism holds the reflective-type circularly polarizing plate, a space is left between the light exit surface of the lighting fixture main body and the reflective-type circularly polarizing plate. ### Claim 6 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the light source includes a plurality of light sources arranged in a single direction. ### Claim 7 (depends on 1) The plant growth lighting fixture according to claim 1, wherein a long side of a minimum rectangle including the main surface of the reflective-type circularly polarizing plate has a length of 1 to 2 m. ### Claim 8 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the support of the reflective-type circularly polarizing plate has a thickness of 0.1 to 5 mm. ### Claim 9 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the reflective-type circularly polarizing plate has a center wavelength of the particular wavelength range, in which circularly polarized light having a particular rotational direction is selectively reflected, in at least one of a wavelength range of 380 to 500 nm or a wavelength range of 600 to 780 nm. ### Claim 10 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the light source is at least one of a light source having an emission center wavelength in a wavelength range of 380 to 500 nm, a light source having an emission center wavelength in a wavelength range of 600 to 780 nm, or a white light source. ### Claim 11 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the light source is an LED. ### Claim 12 (depends on 1) The plant growth lighting fixture according to claim 1, wherein the holding mechanism is an elongated holding member having an L-shaped sectional shape.