# US 12,225,690 B2 · Apparatus having magnetic fluid heat transport system

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- Number: US 12,225,690 B2
- Document ID: US12225690B2
- Status: Granted
- Kind: B2
- Application number: 18/502,629
- Filed: 2023-11-06
- Published: 2024-02-29
- Granted: 2025-02-11
- Earliest claimed: 2021-02-15
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Genki Tanaka; Akira Watanabe; Akinori Inagaki
- Web page: https://patentgrep.com/patent/US12225690B2

## CPC

- H05K 7/20272: {Accessories for moving fluid, for expanding fluid, for connecting fluid conduits, for distributing fluid, for removing gas or for preventing leakage, e.g. pumps, tanks or manifolds}
- H04N 23/52: Elements optimising image sensor operation, e.g. for electromagnetic interference [EMI] protection or temperature control by heat transfer or cooling elements
- H04N 23/60: Control of cameras or camera modules
- H04N 23/687: {by shifting the lens or sensor position}
- H01F 7/02: Permanent magnets {[PM]}
- H01F 7/0294: {Detection, inspection, magnetic treatment}
- H01F 7/20: without armatures (cores H01F3/00; coils H01F5/00 {; shaping metal by applying magnetic forces B21D26/14; electromagnets specially adapted for NMR applications G01R33/381})
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

An apparatus includes a conduit configured to circulate magnetic fluid, and a magnetic field generator that applies a magnetic field to the magnetic fluid. The conduit includes at least four areas of a first conduit area in which the magnetic fluid receives heat from a heating unit, a second conduit area from the first conduit area to a cooling unit, a third conduit area in which the magnetic fluid is cooled by the cooling unit, and a fourth conduit area from the cooling unit to the heating unit. When the apparatus is used, a volume of the magnetic fluid in one of the first to fourth conduit areas, in which a flow direction of the magnetic fluid coincides with a gravity direction, is larger than that of another conduit area, in which the flow direction of the magnetic fluid does not coincide with the gravity direction.

## Claims

### Claim 1

An image pickup apparatus comprising:
an image sensor as a heating portion;
a cooling portion,
a conduit configured to circulate magnetic fluid having temperature sensitivity between the image sensor and the cooling portion;
a magnetic field generator disposed on an object side in an optical axis direction further than the conduit and configured to apply a magnetic field to the magnetic fluid; and,
wherein the conduit includes a first conduit area in which the magnetic fluid receives heat from the image sensor, a second conduit area from the first conduit area to the cooling portion, a third conduit area in which the magnetic fluid is cooled by the cooling portion, and a fourth conduit area from the cooling portion to the image sensor,
wherein, when the image pickup apparatus is viewed from a back side in the optical axis direction, the magnetic field generator is disposed between the first conduit area and the third conduit area, and
wherein a conduit volume inside the first conduit area is larger than that inside any of the second, third and fourth conduit areas.

### Claim 2 (depends on 1)

The image pickup apparatus according to claim 1, wherein a flow direction of the magnetic fluid flowing through the first conduit area coincides with a gravity direction.

### Claim 3 (depends on 2)

The image pickup apparatus according to claim 2 wherein the conduit volume inside the fourth conduit area is larger than that inside the second conduit area.

### Claim 4 (depends on 3)

The image pickup apparatus according to claim 3, wherein a conduit sectional area inside the second conduit area gradually increases from the first conduit area toward the third conduit area.

### Claim 5 (depends on 1)

The image pickup apparatus according to claim 1, wherein, when the image pickup apparatus is viewed from the back side, a magnet constituting the magnetic field generator overlaps the fourth conduit area.

### Claim 6 (depends on 1)

The image pickup apparatus according to claim 1, wherein each of projected areas of the first and third conduit areas on a plane orthogonal to an optical axis is larger than any one of those of the second and fourth conduit areas on the plane.