# US 12,216,268 B2 · Filter unit, filter selection method, and imaging device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,268 B2 - Document ID: US12216268B2 - Status: Granted - Kind: B2 - Application number: 18/175,391 - Filed: 2023-02-27 - Published: 2023-06-29 - Granted: 2025-02-04 - Earliest claimed: 2018-02-09 - Assignees: Sony Group Corporation - Applicants: Sony Group Corporation - Inventors: Takuma Tanae; Hideki Nakamaru - Web page: https://patentgrep.com/patent/US12216268B2 ## CPC - G02B 26/023: {comprising movable attenuating elements, e.g. neutral density filters} - G02B 5/205: {Neutral density filters} - G02B 26/008: {in the form of devices for effecting sequential colour changes, e.g. colour wheels} - G02B 27/281: {used for attenuating light intensity, e.g. comprising rotatable polarising elements} - G02B 27/288: {Filters employing polarising elements, e.g. Lyot or Solc filters (G02B5/3016 takes precedence)} - G03B 11/00: Filters or other obturators specially adapted for photographic purposes - G03B 17/12: with means for supporting objectives, supplementary lenses, filters, masks, or turrets - H04N 23/70: Circuitry for compensating brightness variation in the scene - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The present disclosure relates to a filter unit, a filter selection method, and an imaging device that allow continuously changing a transmittance of an ND filter and switching between filters to be performed more easily. A disk provided with a plurality of filters including an ND filter having a continuously variable transmittance is rotated to cause a filter corresponding to a rotational orientation of the disk among the plurality of filters provided on the disk to be arranged on an optical axis of incident light toward an image sensor. The present disclosure can be applied to, for example, a filter unit, an imaging device, electronic equipment, a filter selection method, a program, or the like. ## Claims ### Claim 1 A filter unit, comprising: a disk provided with a plurality of filters including a neutral density (ND) filter and having a continuously variable transmittance, wherein the ND filter is a polarization filter, the polarization filter has a non-circular shape whose longitudinal direction is in a rotation direction of the disk, and the filter unit is provided between an imaging unit and an ultraviolet cut filter that blocks ultraviolet components contained in an incident light. ### Claim 2 (depends on 1) The filter unit according to claim 1, wherein the disk is configured to rotate about a first direction that passes through a first center of a plane of the disk and is perpendicular to the plane, and the polarization filter is driven to rotate independently from rotational driving of the disk, about a second direction that passes through a second center of the polarization filter and is perpendicular to the plane. ### Claim 3 (depends on 2) The filter unit according to claim 2, comprising a plurality of the disks arranged in a traveling direction of the incident light. ### Claim 4 (depends on 3) The filter unit according to claim 3, wherein each of the plurality of the disks comprises filters of the same types with those of other disks. ### Claim 5 (depends on 3) The filter unit according to claim 3, wherein the plurality of filters further includes, in addition to the ND filter, a through filter that does not optically affect the incident light that passes through the through filter. ### Claim 6 (depends on 3) The filter unit according to claim 3, wherein the plurality of the disks is driven to rotate, independently from each other, about the first direction that passes through the first center of the plane of the disk and is perpendicular to the plane, the polarization filter provided on at least one of the plurality of the disks is driven to rotate, independently from the rotational driving of the corresponding disk, about the second direction that passes through the second center of the polarization filter and is perpendicular to the plane, and the polarization filter is configured to rotate, on an optical axis of the incident light, about the direction that passes through the second center of the polarization filter and is perpendicular to the plane, to change a relative angle between polarization directions of the polarization filter and a polarization filter provided on another one of the disks and cause a transmittance of the ND filter to change. ### Claim 7 (depends on 6) The filter unit according to claim 6, wherein the plurality of the disks is driven to rotate about the first direction that passes through the first center of the plane of the disk and is perpendicular to the plane to cause filters arranged on the optical axis of the incident light to be switched to other filters. ### Claim 8 (depends on 3) The filter unit according to claim 3, wherein the polarization filters having the non-circular shape are each driven to rotate, on an optical axis of the incident light, about the first direction that passes through the center of the plane of the disk and is perpendicular to the plane to change a relative angle between polarization directions of the polarization filters and cause a transmittance of the ND filter to change. ### Claim 9 (depends on 2) The filter unit according to claim 2, further comprising a drive unit that is configured to drive the disk to rotate about a direction that passes through the first center of the plane of the disk and is perpendicular to the plane. ### Claim 10 (depends on 9) The filter unit according to claim 9, wherein the drive unit is further configured to drive the disk to rotate based on application of a force to an outer peripheral portion of the disk. ### Claim 11 (depends on 9) The filter unit according to claim 9, further comprising a control unit that is configured to control the rotational driving of the disk via the drive unit to achieve a desired rotational orientation of the disk. ### Claim 12 (depends on 11) The filter unit according to claim 11, further comprising an orientation detection unit that is configured to detect the rotational orientation of the disk, wherein the control unit is configured to control the rotational driving of the disk based on a result of detection by the orientation detection unit. ### Claim 13 A filter selection method, comprising: rotating a disk provided with a plurality of filters including a neutral density (ND) filter having a continuously variable transmittance, wherein the ND filter is a polarization filter, the polarization filter has a non-circular shape whose longitudinal direction is in a rotation direction of the disk, and the disk provided with the plurality of filters is provided between an imaging unit and an ultraviolet cut filter that blocks ultraviolet components contained in an incident light. ### Claim 14 An imaging device, comprising: an imaging unit configured to capture an image of a subject; and a filter unit having a disk provided with a plurality of filters including a neutral density (ND) filter and having a continuously variable transmittance, wherein the ND filter is a polarization filter, the polarization filter has a non-circular shape whose longitudinal direction is in a rotation direction of the disk, and the filter unit is provided between the imaging unit and an ultraviolet cut filter that blocks ultraviolet components contained in an incident light.